Table of Contents
This chapter will be of interest only to those building and developing Apache HBase (i.e., as opposed to just downloading the latest distribution).
There are two different repositories for Apache HBase: Subversion (SVN) and Git. GIT is our repository of record for all but the Apache HBase website. We used to be on SVN. We migrated. See Migrade Apache HBase SVN Repos to Git. Updating hbase.apache.org still requires use of SVN (See Section 1.6, “Updating hbase.apache.org”). See Source Code Management page for contributor and committer links or seach for HBase on the Apache Git page.
Under the dev-support
folder, you will find hbase_eclipse_formatter.xml
.
We encourage you to have this formatter in place in eclipse when editing HBase code. To load it into eclipse:
Go to Eclipse->Preferences...
In Preferences, Go to Java->Code Style->Formatter
Import... hbase_eclipse_formatter.xml
Click Apply
Still in Preferences, Go to Java->Editor->Save Actions
Check the following:
Perform the selected actions on save
Format source code
Format edited lines
Click Apply
In addition to the automatic formatting, make sure you follow the style guidelines explained in Section 1.11.5, “Common Patch Feedback”
Also, no @author tags - that's a rule. Quality Javadoc comments are appreciated. And include the Apache license.
If you cloned the project via git, download and install the Git plugin (EGit). Attach to your local git repo (via the Git Repositories window) and you'll be able to see file revision history, generate patches, etc.
The easiest way is to use the m2eclipse plugin for Eclipse. Eclipse Indigo or newer has m2eclipse built-in, or it can be found here:http://www.eclipse.org/m2e/. M2Eclipse provides Maven integration for Eclipse - it even lets you use the direct Maven commands from within Eclipse to compile and test your project.
To import the project, you merely need to go to File->Import...Maven->Existing Maven Projects and then point Eclipse at the HBase root directory; m2eclipse will automatically find all the hbase modules for you.
If you install m2eclipse and import HBase in your workspace, you will have to fix your eclipse Build Path.
Remove target
folder, add target/generated-jamon
and target/generated-sources/java
folders. You may also remove from your Build Path
the exclusions on the src/main/resources
and src/test/resources
to avoid error message in the console 'Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.6:run (default) on project hbase:
'An Ant BuildException has occured: Replace: source file .../target/classes/hbase-default.xml doesn't exist'. This will also
reduce the eclipse build cycles and make your life easier when developing.
For those not inclined to use m2eclipse, you can generate the Eclipse files from the command line. First, run (you should only have to do this once):
mvn clean install -DskipTests
and then close Eclipse and execute...
mvn eclipse:eclipse
... from your local HBase project directory in your workspace to generate some new .project
and .classpath
files. Then reopen Eclipse, or refresh your eclipse project (F5), and import
the .project file in the HBase directory to a workspace.
The M2_REPO
classpath variable needs to be set up for the project. This needs to be set to
your local Maven repository, which is usually ~/.m2/repository
If this classpath variable is not configured, you will see compile errors in Eclipse like this:
Description Resource Path Location Type The project cannot be built until build path errors are resolved hbase Unknown Java Problem Unbound classpath variable: 'M2_REPO/asm/asm/3.1/asm-3.1.jar' in project 'hbase' hbase Build path Build Path Problem Unbound classpath variable: 'M2_REPO/com/google/guava/guava/r09/guava-r09.jar' in project 'hbase' hbase Build path Build Path Problem Unbound classpath variable: 'M2_REPO/com/google/protobuf/protobuf-java/2.3.0/protobuf-java-2.3.0.jar' in project 'hbase' hbase Build path Build Path Problem Unbound classpath variable:
Eclipse will currently complain about Bytes.java
. It is not possible to turn these errors off.
Description Resource Path Location Type Access restriction: The method arrayBaseOffset(Class) from the type Unsafe is not accessible due to restriction on required library /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/classes.jar Bytes.java /hbase/src/main/java/org/apache/hadoop/hbase/util line 1061 Java Problem Access restriction: The method arrayIndexScale(Class) from the type Unsafe is not accessible due to restriction on required library /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/classes.jar Bytes.java /hbase/src/main/java/org/apache/hadoop/hbase/util line 1064 Java Problem Access restriction: The method getLong(Object, long) from the type Unsafe is not accessible due to restriction on required library /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/classes.jar Bytes.java /hbase/src/main/java/org/apache/hadoop/hbase/util line 1111 Java Problem
For additional information on setting up Eclipse for HBase development on Windows, see Michael Morello's blog on the topic.
Thanks to maven, building HBase is pretty easy. You can read about the various maven commands in Section 1.8, “Maven Build Commands”, but the simplest command to compile HBase from its java source code is:
mvn package -DskipTests
Or, to clean up before compiling:
mvn clean package -DskipTests
With Eclipse set up as explained above in Section 1.2.1, “Eclipse”, you can also simply use the build command in Eclipse. To create the full installable HBase package takes a little bit more work, so read on.
You may need to change the protobuf definitions that reside in the hbase-protocol module or other modules.
The protobuf files are located hbase-protocol/src/main/protobuf
.
For the change to be effective, you will need to regenerate the classes. You can use maven profile compile-protobuf to do this.
mvn compile -Dcompile-protobuf or mvn compile -Pcompile-protobuf
You may also want to define protoc.path for the protoc binary
mvn compile -Dcompile-protobuf -Dprotoc.path=/opt/local/bin/protoc
Read the hbase-protocol/README.txt
for more details.
If you see Unable to find resource 'VM_global_library.vm'
, ignore it.
Its not an error. It is officially ugly though.
Pass -Dsnappy
to trigger the snappy maven profile for building
snappy native libs into hbase. See also ???
HBase 0.96.x will run on hadoop 1.x or hadoop 2.x. HBase 0.98 will run on both also (but HBase 0.98 deprecates use of hadoop 1). HBase 1.x will NOT run on hadoop 1. In what follows, we make a distinction between HBase 1.x builds and the awkward process involved building HBase 0.96/0.98 for either hadoop 1 or hadoop 2 targets.
Building 0.98 and 0.96, you must choose which hadoop to build against; we cannot make a single HBase binary that can run against both hadoop1 and hadoop2. Since we include the Hadoop we were built against -- so we can do standalone mode -- the set of modules included in the tarball changes dependent on whether the hadoop1 or hadoop2 target is chosen. You can tell which HBase you have -- whether it is for hadoop1 or hadoop2 by looking at the version; the HBase for hadoop1 bundle will include 'hadoop1' in its version. Ditto for hadoop2.
Maven, our build system, natively will not let you have a single product
built against different dependencies. It is understandable. But neither could
we convince maven to change the set of included modules and write out
the correct poms w/ appropriate dependencies even though we have two
build targets; one for hadoop1 and another for hadoop2. So, there is a prestep
required. This prestep takes as input the current pom.xmls and it generates hadoop1 or
hadoop2 versions using a script in dev-tools
called
generate-hadoopX-poms.sh
. You then reference these generated
poms when you build. For now, just be aware of the difference between HBase 1.x
builds and those of HBase 0.96-0.98. Below we will come back to this difference
when we list out build instructions.
Publishing to maven requires you sign the artifacts you want to upload. To have the
build do this for you, you need to make sure you have a properly configured
settings.xml
in your local repository under .m2
.
Here is my ~/.m2/settings.xml
.
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd"> <servers> <!- To publish a snapshot of some part of Maven --> <server> <id>apache.snapshots.https</id> <username>YOUR_APACHE_ID </username> <password>YOUR_APACHE_PASSWORD </password> </server> <!-- To publish a website using Maven --> <!-- To stage a release of some part of Maven --> <server> <id>apache.releases.https</id> <username>YOUR_APACHE_ID </username> <password>YOUR_APACHE_PASSWORD </password> </server> </servers> <profiles> <profile> <id>apache-release</id> <properties> <gpg.keyname>YOUR_KEYNAME</gpg.keyname> <!--Keyname is something like this ... 00A5F21E... do gpg --list-keys to find it--> <gpg.passphrase>YOUR_KEY_PASSWORD </gpg.passphrase> </properties> </profile> </profiles> </settings>
You must use maven 3.0.x (Check by running mvn -version).
I'll explain by running through the process. See later in this section for more detail on particular steps. These instructions are for building HBase 1.0.x. For building earlier versions, the process is different. See this section under the respective release documentation folders.
If you are making a point release (for example to quickly address a critical incompatability or security problem) off of a release branch instead of a development branch the tagging instructions are slightly different. I'll prefix those special steps with Point Release Only.
I would advise before you go about making a release candidate, do a practise run by deploying a SNAPSHOT. Also, make sure builds have been passing recently for the branch from where you are going to take your release. You should also have tried recent branch tips out on a cluster under load running for instance our hbase-it integration test suite for a few hours to 'burn in' the near-candidate bits.
At this point you should tag the previous release branch (ex: 0.96.1) with the new point release tag (e.g. 0.96.1.1 tag). Any commits with changes or mentioned below for the point release should be appled to the new tag.
The Hadoop How To Release wiki page informs much of the below and may have more detail on particular sections so it is worth review.
Update CHANGES.txt with the changes since the last release. Make sure the URL to the JIRA points to the properly location listing fixes for this release. Adjust the version in all the poms appropriately. If you are making a release candidate, you must remove the -SNAPSHOT from all versions. If you are running this receipe to publish a SNAPSHOT, you must keep the -SNAPSHOT suffix on the hbase version. The Versions Maven Plugin can be of use here. To set a version in all the many poms of the hbase multi-module project, do something like this:
$ mvn clean org.codehaus.mojo:versions-maven-plugin:1.3.1:set -DnewVersion=0.96.0
Checkin the CHANGES.txt
and any version changes.
Update the documentation under src/main/docbkx
. This usually involves copying the
latest from trunk making version-particular adjustments to suit this release candidate version.
Now, build the src tarball. This tarball is hadoop version independent. It is just the pure src code and documentation without a particular hadoop taint, etc.
Add the -Prelease
profile when building; it checks files for licenses and will fail the build if unlicensed files present.
$ MAVEN_OPTS="-Xmx2g" mvn clean install -DskipTests assembly:single -Dassembly.file=hbase-assembly/src/main/assembly/src.xml -Prelease
Undo the tarball and make sure it looks good. A good test for the src tarball being 'complete' is to see if
you can build new tarballs from this source bundle.
If the source tarball is good, save it off to a version directory, i.e a directory somewhere where you are collecting
all of the tarballs you will publish as part of the release candidate. For example if we were building a
hbase-0.96.0 release candidate, we might call the directory hbase-0.96.0RC0
. Later
we will publish this directory as our release candidate up on people.apache.org/~YOU.
Now lets build the binary tarball.
Add the -Prelease
profile when building; it checks files for licenses and will fail the build if unlicensed files present.
Do it in two steps. First install into the local repository and then generate documentation and assemble the tarball
(Otherwise build complains that hbase modules are not in maven repo when we try to do it all in the one go especially on fresh repo).
It seems that you need the install goal in both steps.
$ MAVEN_OPTS="-Xmx3g" mvn clean install -DskipTests -Prelease $ MAVEN_OPTS="-Xmx3g" mvn install -DskipTests site assembly:single -Prelease
Undo the generated tarball and check it out. Look at doc. and see if it runs, etc. If good, copy the tarball to the above mentioned version directory.
The following step that creates a new tag can be skipped since you've already created the point release tag
I'll tag the release at this point since its looking good. If we find an issue later, we can delete the tag and start over. Release needs to be tagged when we do next step.
Now deploy hbase to the apache maven repository.
This time we use the apache-release
profile instead of just release
profile when doing mvn deploy;
it will invoke the apache pom referenced by our poms. It will also sign your artifacts published to mvn as long as your settings.xml in your local .m2
repository is configured correctly (your settings.xml
adds your gpg password property to the apache profile).
$ MAVEN_OPTS="-Xmx3g" mvn deploy -DskipTests -Papache-release
The last command above copies all artifacts up to a temporary staging apache mvn repo in an 'open' state. We'll need to do more work on these maven artifacts to make them generally available.
The script dev-support/make_rc.sh
automates alot of the above listed release steps.
It does not do the modification of the CHANGES.txt for the release, the close of the
staging repository up in apache maven (human intervention is needed here), the checking of
the produced artifacts to ensure they are 'good' -- e.g. undoing the produced tarballs, eyeballing them to make
sure they look right then starting and checking all is running properly -- and then the signing and pushing of
the tarballs to people.apache.org but it does the other stuff; it can come in handy.
Now lets get back to what is up in maven. Our artifacts should be up in maven repository in the staging area in the 'open' state. While in this 'open' state you can check out what you've published to make sure all is good. To do this, login at repository.apache.org using your apache id. Find your artifacts in the staging repository. Browse the content. Make sure all artifacts made it up and that the poms look generally good. If it checks out, 'close' the repo. This will make the artifacts publically available. You will receive an email with the URL to give out for the temporary staging repository for others to use trying out this new release candidate. Include it in the email that announces the release candidate. Folks will need to add this repo URL to their local poms or to their local settings.xml file to pull the published release candidate artifacts. If the published artifacts are incomplete or borked, just delete the 'open' staged artifacts.
See the hbase-downstreamer test for a simple example of a project that is downstream of hbase an depends on it. Check it out and run its simple test to make sure maven artifacts are properly deployed to the maven repository. Be sure to edit the pom to point at the proper staging repo. Make sure you are pulling from the repo when tests run and that you are not getting from your local repo (pass -U or delete your local repo content and check maven is pulling from remote out of the staging repo).
See Publishing Maven Artifacts for some pointers on this maven staging process.
We no longer publish using the maven release plugin. Instead we do mvn deploy. It seems to give us a backdoor to maven release publishing. If no -SNAPSHOT on the version string, then we are 'deployed' to the apache maven repository staging directory from which we can publish URLs for candidates and later, if they pass, publish as release (if a -SNAPSHOT on the version string, deploy will put the artifacts up into apache snapshot repos).
If the hbase version ends in -SNAPSHOT
, the artifacts go elsewhere. They are put into the apache snapshots repository
directly and are immediately available. Making a SNAPSHOT release, this is what you want to happen.
At this stage we have two tarballs in our 'version directory' and a set of artifacts up in maven in staging area in the
'closed' state publically available in a temporary staging repository whose URL you should have gotten in an email.
The above mentioned script, make_rc.sh
does all of the above for you minus the check of the artifacts built,
the closing of the staging repository up in maven, and the tagging of the release. If you run the script, do your checks at this
stage verifying the src and bin tarballs and checking what is up in staging using hbase-downstreamer project. Tag before you start
the build. You can always delete it if the build goes haywire.
If all checks out, next put the version directory up on people.apache.org. You will need to sign and fingerprint them before you push them up. In the version directory do this:
$ for i in *.tar.gz; do echo $i; gpg --print-mds $i > $i.mds ; done $ for i in *.tar.gz; do echo $i; gpg --armor --output $i.asc --detach-sig $i ; done $ cd .. # Presuming our 'version directory' is named 0.96.0RC0, now copy it up to people.apache.org. $ rsync -av 0.96.0RC0 people.apache.org:public_html
Make sure the people.apache.org directory is showing and that the mvn repo urls are good. Announce the release candidate on the mailing list and call a vote.
Make sure your settings.xml
is set up properly (see above for how).
Make sure the hbase version includes -SNAPSHOT
as a suffix. Here is how I published SNAPSHOTS of
a release that had an hbase version of 0.96.0 in its poms.
$ MAVEN_OPTS="-Xmx3g" mvn clean install -DskipTests javadoc:aggregate site assembly:single -Prelease $ MAVEN_OPTS="-Xmx3g" mvn -DskipTests deploy -Papache-release
The make_rc.sh
script mentioned above in the
(see Section 1.4.2, “Making a Release Candidate”) can help you publish SNAPSHOTS
.
Make sure your hbase.version has a -SNAPSHOT
suffix and then run
the script. It will put a snapshot up into the apache snapshot repository for you.
The manual is marked up using docbook.
We then use the docbkx maven plugin
to transform the markup to html. This plugin is run when you specify the site
goal as in when you run mvn site or you can call the plugin explicitly to
just generate the manual by doing mvn docbkx:generate-html
(TODO: It looks like you have to run mvn site first because docbkx wants to
include a transformed hbase-default.xml
. Fix).
When you run mvn site, we do the document generation twice, once to generate the multipage
manual and then again for the single page manual (the single page version is easier to search).
The Apache HBase apache web site (including this reference guide) is maintained as part of the main
Apache HBase source tree, under /src/main/docbkx
and /src/main/site
[1].
The former -- docbkx -- is this reference guide as a bunch of xml marked up using docbook;
the latter is the hbase site (the navbars, the header, the layout, etc.),
and some of the documentation, legacy pages mostly that are in the process of being merged into the docbkx tree that is
converted to html by a maven plugin by the site build.
To contribute to the reference guide, edit these files under site or docbkx and submit them as a patch (see Section 1.11, “Submitting Patches”). Your Jira should contain a summary of the changes in each section (see HBASE-6081 for an example).
To generate the site locally while you're working on it, run:
mvn site
Then you can load up the generated HTML files in your browser (file are under /target/site
).
As of INFRA-5680 Migrate apache hbase website,
to publish the website, build it, and then deploy it over a checkout of https://svn.apache.org/repos/asf/hbase/hbase.apache.org/trunk
.
Finally, check it in. For example, if trunk is checked out out at /Users/stack/checkouts/trunk
and the hbase website, hbase.apache.org, is checked out at /Users/stack/checkouts/hbase.apache.org/trunk
, to update
the site, do the following:
# Build the site and deploy it to the checked out directory # Getting the javadoc into site is a little tricky. You have to build it before you invoke 'site'. $ MAVEN_OPTS=" -Xmx3g" mvn clean install -DskipTests javadoc:aggregate site site:stage -DstagingDirectory=/Users/stack/checkouts/hbase.apache.org/trunk
Now check the deployed site by viewing in a brower, browse to file:////Users/stack/checkouts/hbase.apache.org/trunk/index.html and check all is good. If all checks out, commit it and your new build will show up immediately at http://hbase.apache.org
$ cd /Users/stack/checkouts/hbase.apache.org/trunk $ svn status # Do an svn add of any new content... $ svn add .... $ svn commit -m 'Committing latest version of website...'
Developers, at a minimum, should familiarize themselves with the unit test detail; unit tests in HBase have a character not usually seen in other projects.
As of 0.96, Apache HBase is split into multiple modules which creates "interesting" rules for
how and where tests are written. If you are writing code for
hbase-server
, see Section 1.7.2, “Unit Tests” for
how to write your tests; these tests can spin up a minicluster and will need to be
categorized. For any other module, for example hbase-common
,
the tests must be strict unit tests and just test the class under test - no use of
the HBaseTestingUtility or minicluster is allowed (or even possible given the
dependency tree).
If the module you are developing in has no other dependencies on other HBase modules, then you can cd into that module and just run:
mvn test
which will just run the tests IN THAT MODULE. If there are other dependencies on other modules, then you will have run the command from the ROOT HBASE DIRECTORY. This will run the tests in the other modules, unless you specify to skip the tests in that module. For instance, to skip the tests in the hbase-server module, you would run:
mvn clean test -PskipServerTests
from the top level directory to run all the tests in modules other than hbase-server. Note that you
can specify to skip tests in multiple modules as well as just for a single module. For example, to skip
the tests in hbase-server
and hbase-common
, you would run:
mvn clean test -PskipServerTests -PskipCommonTests
Also, keep in mind that if you are running tests in the hbase-server
module you will need to
apply the maven profiles discussed in Section 1.7.3, “Running tests” to get the tests to run properly.
Apache HBase unit tests are subdivided into four categories: small, medium, large, and
integration with corresponding JUnit categories:
SmallTests
, MediumTests
,
LargeTests
, IntegrationTests
.
JUnit categories are denoted using java annotations and look like this in your unit test code.
... @Category(SmallTests.class) public class TestHRegionInfo { @Test public void testCreateHRegionInfoName() throws Exception { // ... } }
The above example shows how to mark a unit test as belonging to the small category. All unit tests in HBase have a categorization.
The first three categories, small, medium, and large are for tests run when you
type $ mvn test
; i.e. these three categorizations are for HBase unit
tests. The integration category is for not for unit tests but for integration tests.
These are run when you invoke $ mvn verify
. Integration tests are
described in Section 1.7.5, “Integration Tests” and will not be discussed further in this section
on HBase unit tests.
Apache HBase uses a patched maven surefire plugin and maven profiles to implement its unit test characterizations.
Read the below to figure which annotation of the set small, medium, and large to put on your new HBase unit test.
Small tests are executed in a shared JVM. We put in this category all the tests that can be executed quickly in a shared JVM. The maximum execution time for a small test is 15 seconds, and small tests should not use a (mini)cluster.
Medium tests represent tests that must be executed before proposing a patch. They are designed to run in less than 30 minutes altogether, and are quite stable in their results. They are designed to last less than 50 seconds individually. They can use a cluster, and each of them is executed in a separate JVM.
Large tests are everything else. They are typically large-scale tests, regression tests for specific bugs, timeout tests, performance tests. They are executed before a commit on the pre-integration machines. They can be run on the developer machine as well.
Integration tests are system level tests. See Section 1.7.5, “Integration Tests” for more info.
Below we describe how to run the Apache HBase junit categories.
Running
mvn test
will execute all small tests in a single JVM (no fork) and then medium tests in a separate JVM for each test instance. Medium tests are NOT executed if there is an error in a small test. Large tests are NOT executed. There is one report for small tests, and one report for medium tests if they are executed.
Running
mvn test -P runAllTests
will execute small tests in a single JVM then medium and large tests in a separate JVM for each test. Medium and large tests are NOT executed if there is an error in a small test. Large tests are NOT executed if there is an error in a small or medium test. There is one report for small tests, and one report for medium and large tests if they are executed.
To run an individual test, e.g. MyTest
, do
mvn test -Dtest=MyTest
You can also pass multiple, individual tests as a comma-delimited list:
mvn test -Dtest=MyTest1,MyTest2,MyTest3
You can also pass a package, which will run all tests under the package:
mvn test '-Dtest=org.apache.hadoop.hbase.client.*'
When -Dtest
is specified, localTests
profile will
be used. It will use the official release of maven surefire, rather than our
custom surefire plugin, and the old connector (The HBase build uses a patched
version of the maven surefire plugin). Each junit tests is executed in a
separate JVM (A fork per test class). There is no parallelization when tests are
running in this mode. You will see a new message at the end of the -report:
"[INFO] Tests are skipped". It's harmless. While you need to make sure the sum
of Tests run:
in the Results :
section of test reports
matching the number of tests you specified because no error will be reported
when a non-existent test case is specified.
Running mvn test -P runSmallTests will execute "small" tests only, using a single JVM.
Running mvn test -P runMediumTests will execute "medium" tests only, launching a new JVM for each test-class.
Running mvn test -P runLargeTests will execute "large" tests only, launching a new JVM for each test-class.
For convenience, you can run mvn test -P runDevTests to execute both small and medium tests, using a single JVM.
By default, $ mvn test -P runAllTests
runs 5 tests in parallel.
It can be increased on a developer's machine. Allowing that you can have 2 tests
in parallel per core, and you need about 2Gb of memory per test (at the
extreme), if you have an 8 core, 24Gb box, you can have 16 tests in parallel.
but the memory available limits it to 12 (24/2), To run all tests with 12 tests
in parallel, do this: mvn test -P runAllTests
-Dsurefire.secondPartThreadCount=12. To increase the speed, you
can as well use a ramdisk. You will need 2Gb of memory to run all tests. You
will also need to delete the files between two test run. The typical way to
configure a ramdisk on Linux is:
$ sudo mkdir /ram2G sudo mount -t tmpfs -o size=2048M tmpfs /ram2G
You can then use it to run all HBase tests with the command:
mvn test -P runAllTests -Dsurefire.secondPartThreadCount=12 -Dtest.build.data.basedirectory=/ram2G
It's also possible to use the script hbasetests.sh. This
script runs the medium and large tests in parallel with two maven instances, and
provides a single report. This script does not use the hbase version of surefire
so no parallelization is being done other than the two maven instances the
script sets up. It must be executed from the directory which contains the
pom.xml
.
For example running ./dev-support/hbasetests.sh will execute small and medium tests. Running ./dev-support/hbasetests.sh runAllTests will execute all tests. Running ./dev-support/hbasetests.sh replayFailed will rerun the failed tests a second time, in a separate jvm and without parallelisation.
A custom Maven SureFire plugin listener checks a number of resources before
and after each HBase unit test runs and logs its findings at the end of the test
output files which can be found in target/surefire-reports
per Maven module (Tests write test reports named for the test class into this
directory. Check the *-out.txt
files). The resources
counted are the number of threads, the number of file descriptors, etc. If the
number has increased, it adds a LEAK? comment in the logs.
As you can have an HBase instance running in the background, some threads can be
deleted/created without any specific action in the test. However, if the test
does not work as expected, or if the test should not impact these resources,
it's worth checking these log lines
...hbase.ResourceChecker(157): before...
and ...hbase.ResourceChecker(157): after...
.
For example:
2012-09-26 09:22:15,315 INFO [pool-1-thread-1] hbase.ResourceChecker(157): after: regionserver.TestColumnSeeking#testReseeking Thread=65 (was 65), OpenFileDescriptor=107 (was 107), MaxFileDescriptor=10240 (was 10240), ConnectionCount=1 (was 1)
As much as possible, tests should be written as category small tests.
All tests must be written to support parallel execution on the same machine, hence they should not use shared resources as fixed ports or fixed file names.
Tests should not overlog. More than 100 lines/second makes the logs complex to read and use i/o that are hence not available for the other tests.
Tests can be written with HBaseTestingUtility
.
This class offers helper functions to create a temp directory and do the
cleanup, or to start a cluster.
All tests must be categorized, if not they could be skipped.
All tests should be written to be as fast as possible.
Small category tests should last less than 15 seconds, and must not have any side effect.
Medium category tests should last less than 50 seconds.
Large category tests should last less than 3 minutes. This should ensure a good parallelization for people using it, and ease the analysis when the test fails.
Whenever possible, tests should not use Thread.sleep
,
but rather waiting for the real event they need. This is faster and clearer for
the reader. Tests should not do a Thread.sleep
without
testing an ending condition. This allows understanding what the test is waiting
for. Moreover, the test will work whatever the machine performance is. Sleep
should be minimal to be as fast as possible. Waiting for a variable should be
done in a 40ms sleep loop. Waiting for a socket operation should be done in a
200 ms sleep loop.
Tests using a HRegion do not have to start a cluster: A region can use the
local file system. Start/stopping a cluster cost around 10 seconds. They should
not be started per test method but per test class. Started cluster must be
shutdown using HBaseTestingUtility#shutdownMiniCluster
,
which cleans the directories. As most as possible, tests should use the default
settings for the cluster. When they don't, they should document it. This will
allow to share the cluster later.
HBase integration/system tests are tests that are beyond HBase unit tests. They are generally long-lasting, sizeable (the test can be asked to 1M rows or 1B rows), targetable (they can take configuration that will point them at the ready-made cluster they are to run against; integration tests do not include cluster start/stop code), and verifying success, integration tests rely on public APIs only; they do not attempt to examine server internals asserting success/fail. Integration tests are what you would run when you need to more elaborate proofing of a release candidate beyond what unit tests can do. They are not generally run on the Apache Continuous Integration build server, however, some sites opt to run integration tests as a part of their continuous testing on an actual cluster.
Integration tests currently live under the src/test
directory in the hbase-it submodule and will match the regex:
**/IntegrationTest*.java
. All integration tests are also
annotated with @Category(IntegrationTests.class)
.
Integration tests can be run in two modes: using a mini cluster, or against an
actual distributed cluster. Maven failsafe is used to run the tests using the mini
cluster. IntegrationTestsDriver class is used for executing the tests against a
distributed cluster. Integration tests SHOULD NOT assume that they are running
against a mini cluster, and SHOULD NOT use private API's to access cluster state. To
interact with the distributed or mini cluster uniformly,
IntegrationTestingUtility
, and HBaseCluster
classes,
and public client API's can be used.
On a distributed cluster, integration tests that use ChaosMonkey or otherwise
manipulate services thru cluster manager (e.g. restart regionservers) use SSH to do
it. To run these, test process should be able to run commands on remote end, so ssh
should be configured accordingly (for example, if HBase runs under hbase user in
your cluster, you can set up passwordless ssh for that user and run the test also
under it). To facilitate that, hbase.it.clustermanager.ssh.user
,
hbase.it.clustermanager.ssh.opts
and
hbase.it.clustermanager.ssh.cmd
configuration settings can be used.
"User" is the remote user that cluster manager should use to perform ssh commands.
"Opts" contains additional options that are passed to SSH (for example, "-i
/tmp/my-key"). Finally, if you have some custom environment setup, "cmd" is the
override format for the entire tunnel (ssh) command. The default string is
{/usr/bin/ssh %1$s %2$s%3$s%4$s "%5$s"
} and is a good starting
point. This is a standard Java format string with 5 arguments that is used to
execute the remote command. The argument 1 (%1$s) is SSH options set the via opts
setting or via environment variable, 2 is SSH user name, 3 is "@" if username is set
or "" otherwise, 4 is the target host name, and 5 is the logical command to execute
(that may include single quotes, so don't use them). For example, if you run the
tests under non-hbase user and want to ssh as that user and change to hbase on
remote machine, you can use {/usr/bin/ssh %1$s %2$s%3$s%4$s "su hbase - -c
\"%5$s\""
}. That way, to kill RS (for example) integration tests may run
{/usr/bin/ssh some-hostname "su hbase - -c \"ps aux | ... | kill
...\""
}. The command is logged in the test logs, so you can verify it is
correct for your environment.
HBase 0.92 added a verify
maven target. Invoking it, for
example by doing mvn verify
, will run all the phases up to and
including the verify phase via the maven failsafe
plugin, running all the above mentioned HBase unit tests as well as
tests that are in the HBase integration test group. After you have completed
mvn install -DskipTests You can run just the integration
tests by invoking:
cd hbase-it mvn verify
If you just want to run the integration tests in top-level, you need to run two commands. First: mvn failsafe:integration-test This actually runs ALL the integration tests.
This command will always output BUILD SUCCESS
even if there
are test failures.
At this point, you could grep the output by hand looking for failed tests. However, maven will do this for us; just use: mvn failsafe:verify The above command basically looks at all the test results (so don't remove the 'target' directory) for test failures and reports the results.
This is very similar to how you specify running a subset of unit tests
(see above), but use the property it.test
instead of
test
. To just run
IntegrationTestClassXYZ.java
, use: mvn
failsafe:integration-test -Dit.test=IntegrationTestClassXYZ
The next thing you might want to do is run groups of integration tests, say
all integration tests that are named IntegrationTestClassX*.java:
mvn failsafe:integration-test -Dit.test=*ClassX* This
runs everything that is an integration test that matches *ClassX*. This
means anything matching: "**/IntegrationTest*ClassX*". You can also run
multiple groups of integration tests using comma-delimited lists (similar to
unit tests). Using a list of matches still supports full regex matching for
each of the groups.This would look something like: mvn
failsafe:integration-test -Dit.test=*ClassX*, *ClassY
If you have an already-setup HBase cluster, you can launch the integration
tests by invoking the class IntegrationTestsDriver
. You may have to
run test-compile first. The configuration will be picked by the bin/hbase
script.
mvn test-compile
Then launch the tests with:
bin/hbase [--config config_dir] org.apache.hadoop.hbase.IntegrationTestsDriver
Pass -h
to get usage on this sweet tool. Running the
IntegrationTestsDriver without any argument will launch tests found under
hbase-it/src/test
, having
@Category(IntegrationTests.class)
annotation, and a name
starting with IntegrationTests
. See the usage, by passing -h, to
see how to filter test classes. You can pass a regex which is checked against
the full class name; so, part of class name can be used. IntegrationTestsDriver
uses Junit to run the tests. Currently there is no support for running
integration tests against a distributed cluster using maven (see HBASE-6201).
The tests interact with the distributed cluster by using the methods in the
DistributedHBaseCluster
(implementing
HBaseCluster
) class, which in turn uses a pluggable
ClusterManager
. Concrete implementations provide actual
functionality for carrying out deployment-specific and environment-dependent
tasks (SSH, etc). The default ClusterManager
is
HBaseClusterManager
, which uses SSH to remotely execute
start/stop/kill/signal commands, and assumes some posix commands (ps, etc). Also
assumes the user running the test has enough "power" to start/stop servers on
the remote machines. By default, it picks up HBASE_SSH_OPTS, HBASE_HOME,
HBASE_CONF_DIR
from the env, and uses
bin/hbase-daemon.sh
to carry out the actions. Currently tarball
deployments, deployments which uses hbase-daemons.sh, and Apache Ambari
deployments are supported. /etc/init.d/ scripts are not supported for now, but
it can be easily added. For other deployment options, a ClusterManager can be
implemented and plugged in.
In 0.96, a tool named ChaosMonkey
has been introduced. It is
modeled after the same-named
tool by Netflix. Some of the tests use ChaosMonkey to simulate faults
in the running cluster in the way of killing random servers, disconnecting
servers, etc. ChaosMonkey can also be used as a stand-alone tool to run a
(misbehaving) policy while you are running other tests.
ChaosMonkey defines Action's and Policy's. Actions are sequences of events. We have at least the following actions:
Restart active master (sleep 5 sec)
Restart random regionserver (sleep 5 sec)
Restart random regionserver (sleep 60 sec)
Restart META regionserver (sleep 5 sec)
Restart ROOT regionserver (sleep 5 sec)
Batch restart of 50% of regionservers (sleep 5 sec)
Rolling restart of 100% of regionservers (sleep 5 sec)
Policies on the other hand are responsible for executing the actions based on a strategy. The default policy is to execute a random action every minute based on predefined action weights. ChaosMonkey executes predefined named policies until it is stopped. More than one policy can be active at any time.
To run ChaosMonkey as a standalone tool deploy your HBase cluster as usual. ChaosMonkey uses the configuration from the bin/hbase script, thus no extra configuration needs to be done. You can invoke the ChaosMonkey by running:
bin/hbase org.apache.hadoop.hbase.util.ChaosMonkey
This will output smt like:
12/11/19 23:21:57 INFO util.ChaosMonkey: Using ChaosMonkey Policy: class org.apache.hadoop.hbase.util.ChaosMonkey$PeriodicRandomActionPolicy, period:60000 12/11/19 23:21:57 INFO util.ChaosMonkey: Sleeping for 26953 to add jitter 12/11/19 23:22:24 INFO util.ChaosMonkey: Performing action: Restart active master 12/11/19 23:22:24 INFO util.ChaosMonkey: Killing master:master.example.com,60000,1353367210440 12/11/19 23:22:24 INFO hbase.HBaseCluster: Aborting Master: master.example.com,60000,1353367210440 12/11/19 23:22:24 INFO hbase.ClusterManager: Executing remote command: ps aux | grep master | grep -v grep | tr -s ' ' | cut -d ' ' -f2 | xargs kill -s SIGKILL , hostname:master.example.com 12/11/19 23:22:25 INFO hbase.ClusterManager: Executed remote command, exit code:0 , output: 12/11/19 23:22:25 INFO hbase.HBaseCluster: Waiting service:master to stop: master.example.com,60000,1353367210440 12/11/19 23:22:25 INFO hbase.ClusterManager: Executing remote command: ps aux | grep master | grep -v grep | tr -s ' ' | cut -d ' ' -f2 , hostname:master.example.com 12/11/19 23:22:25 INFO hbase.ClusterManager: Executed remote command, exit code:0 , output: 12/11/19 23:22:25 INFO util.ChaosMonkey: Killed master server:master.example.com,60000,1353367210440 12/11/19 23:22:25 INFO util.ChaosMonkey: Sleeping for:5000 12/11/19 23:22:30 INFO util.ChaosMonkey: Starting master:master.example.com 12/11/19 23:22:30 INFO hbase.HBaseCluster: Starting Master on: master.example.com 12/11/19 23:22:30 INFO hbase.ClusterManager: Executing remote command: /homes/enis/code/hbase-0.94/bin/../bin/hbase-daemon.sh --config /homes/enis/code/hbase-0.94/bin/../conf start master , hostname:master.example.com 12/11/19 23:22:31 INFO hbase.ClusterManager: Executed remote command, exit code:0 , output:starting master, logging to /homes/enis/code/hbase-0.94/bin/../logs/hbase-enis-master-master.example.com.out .... 12/11/19 23:22:33 INFO util.ChaosMonkey: Started master: master.example.com,60000,1353367210440 12/11/19 23:22:33 INFO util.ChaosMonkey: Sleeping for:51321 12/11/19 23:23:24 INFO util.ChaosMonkey: Performing action: Restart random region server 12/11/19 23:23:24 INFO util.ChaosMonkey: Killing region server:rs3.example.com,60020,1353367027826 12/11/19 23:23:24 INFO hbase.HBaseCluster: Aborting RS: rs3.example.com,60020,1353367027826 12/11/19 23:23:24 INFO hbase.ClusterManager: Executing remote command: ps aux | grep regionserver | grep -v grep | tr -s ' ' | cut -d ' ' -f2 | xargs kill -s SIGKILL , hostname:rs3.example.com 12/11/19 23:23:25 INFO hbase.ClusterManager: Executed remote command, exit code:0 , output: 12/11/19 23:23:25 INFO hbase.HBaseCluster: Waiting service:regionserver to stop: rs3.example.com,60020,1353367027826 12/11/19 23:23:25 INFO hbase.ClusterManager: Executing remote command: ps aux | grep regionserver | grep -v grep | tr -s ' ' | cut -d ' ' -f2 , hostname:rs3.example.com 12/11/19 23:23:25 INFO hbase.ClusterManager: Executed remote command, exit code:0 , output: 12/11/19 23:23:25 INFO util.ChaosMonkey: Killed region server:rs3.example.com,60020,1353367027826. Reported num of rs:6 12/11/19 23:23:25 INFO util.ChaosMonkey: Sleeping for:60000 12/11/19 23:24:25 INFO util.ChaosMonkey: Starting region server:rs3.example.com 12/11/19 23:24:25 INFO hbase.HBaseCluster: Starting RS on: rs3.example.com 12/11/19 23:24:25 INFO hbase.ClusterManager: Executing remote command: /homes/enis/code/hbase-0.94/bin/../bin/hbase-daemon.sh --config /homes/enis/code/hbase-0.94/bin/../conf start regionserver , hostname:rs3.example.com 12/11/19 23:24:26 INFO hbase.ClusterManager: Executed remote command, exit code:0 , output:starting regionserver, logging to /homes/enis/code/hbase-0.94/bin/../logs/hbase-enis-regionserver-rs3.example.com.out 12/11/19 23:24:27 INFO util.ChaosMonkey: Started region server:rs3.example.com,60020,1353367027826. Reported num of rs:6
As you can see from the log, ChaosMonkey started the default PeriodicRandomActionPolicy, which is configured with all the available actions, and ran RestartActiveMaster and RestartRandomRs actions. ChaosMonkey tool, if run from command line, will keep on running until the process is killed.
All commands executed from the local HBase project directory.
Note: use Maven 3 (Maven 2 may work but we suggest you use Maven 3).
See the Section 1.7.3, “Running tests” section above in Section 1.7.2, “Unit Tests”
As of 0.96, Apache HBase supports building against Apache Hadoop versions: 1.0.3, 2.0.0-alpha and 3.0.0-SNAPSHOT. By default, in 0.96 and earlier, we will build with Hadoop-1.0.x. As of 0.98, Hadoop 1.x is deprecated and Hadoop 2.x is the default. To change the version to build against, add a hadoop.profile property when you invoke mvn:
mvn -Dhadoop.profile=1.0 ...
The above will build against whatever explicit hadoop 1.x version we have in our pom.xml
as our '1.0' version.
Tests may not all pass so you may need to pass -DskipTests
unless you are inclined to fix the failing tests.
You will see ERRORs like the above title if you pass the default profile; e.g. if you pass hadoop.profile=1.1 when building 0.96 or hadoop.profile=2.0 when building hadoop 0.98; just drop the hadoop.profile stipulation in this case to get your build to run again. This seems to be a maven pecularity that is probably fixable but we've not spent the time trying to figure it.
Similarly, for 3.0, you would just replace the profile value. Note that Hadoop-3.0.0-SNAPSHOT does not currently have a deployed maven artificat - you will need to build and install your own in your local maven repository if you want to run against this profile.
In earilier versions of Apache HBase, you can build against older versions of Apache Hadoop, notably, Hadoop 0.22.x and 0.23.x. If you are running, for example HBase-0.94 and wanted to build against Hadoop 0.23.x, you would run with:
mvn -Dhadoop.profile=22 ...
Apache HBase gets better only when people contribute!
As Apache HBase is an Apache Software Foundation project, see ??? for more information about how the ASF functions.
Sign up for the dev-list and the user-list. See the mailing lists page. Posing questions - and helping to answer other people's questions - is encouraged! There are varying levels of experience on both lists so patience and politeness are encouraged (and please stay on topic.)
Check for existing issues in Jira. If it's either a new feature request, enhancement, or a bug, file a ticket.
The following is a guideline on setting Jira issue priorities:
Blocker: Should only be used if the issue WILL cause data loss or cluster instability reliably.
Critical: The issue described can cause data loss or cluster instability in some cases.
Major: Important but not tragic issues, like updates to the client API that will add a lot of much-needed functionality or significant bugs that need to be fixed but that don't cause data loss.
Minor: Useful enhancements and annoying but not damaging bugs.
Trivial: Useful enhancements but generally cosmetic.
Most development is done on the master branch (TRUNK). However, there are branches for minor releases (e.g., 0.90.1, 0.90.2, and 0.90.3 are on the 0.90 branch).
In HBase we use JUnit 4.
If you need to run miniclusters of HDFS, ZooKeeper, HBase, or MapReduce testing,
be sure to checkout the HBaseTestingUtility
.
Alex Baranau of Sematext describes how it can be used in
HBase Case-Study: Using HBaseTestingUtility for Local Testing and Development (2010).
Sometimes you don't need a full running server
unit testing. For example, some methods can make do with a
a org.apache.hadoop.hbase.Server
instance
or a org.apache.hadoop.hbase.master.MasterServices
Interface reference rather than a full-blown
org.apache.hadoop.hbase.master.HMaster
.
In these cases, you maybe able to get away with a mocked
Server
instance. For example:
TODO...
See Section 1.2.1.1, “Code Formatting” and Section 1.11.5, “Common Patch Feedback”.
Interfaces are classified both by audience and by stability level. These labels appear at the head of a class. The conventions followed by HBase are inherited by its parent project, Hadoop.
The following interface classifications are commonly used:
@InterfaceAudience
@InterfaceAudience.Public
APIs for users and HBase applications. These APIs will be deprecated through major versions of HBase.
@InterfaceAudience.Private
APIs for HBase internals developers. No guarantees on
compatibility or availability in future versions. Private interfaces
do not need an @InterfaceStability
classification.
@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)
APIs for HBase coprocessor writers. As of HBase 0.92/0.94/0.96/0.98 this api is still unstable. No guarantees on compatibility with future versions.
@InterfaceAudience
ClassificationPackages without an @InterfaceAudience
label are
considered private. Mark your new packages if publicly
accessible.
Only interfaces classified @InterfaceAudience.Public
should
be included in API documentation (Javadoc). Committers must add new package
excludes ExcludePackageNames
section of the
pom.xml
for new packages which do not contain
public classes.
@InterfaceStability
@InterfaceStability
is important for packages marked
@InterfaceAudience.Public
.
@InterfaceStability.Stable
Public packages marked as stable cannot be changed without a deprecation path or a very good reason.
@InterfaceStability.Unstable
Public packages marked as unstable can be changed without a deprecation path.
@InterfaceStability.Evolving
Public packages marked as evolving may be changed, but it is discouraged.
@InterfaceStability
LabelPublic classes with no @InterfaceStability
label are
discouraged, and should be considered implicitly unstable.
If you are unclear about how to mark packages, ask on the development list.
We don't have many but what we have we list below. All are subject to challenge of course but until then, please hold to the rules of the road.
ZooKeeper state should transient (treat it like memory). If deleted, hbase should be able to recover and essentially be in the same state[2].
If you are developing Apache HBase, frequently it is useful to test your changes against a more-real cluster than what you find in unit tests. In this case, HBase can be run directly from the source in local-mode. All you need to do is run:
${HBASE_HOME}/bin/start-hbase.sh
This will spin up a full local-cluster, just as if you had packaged up HBase and installed it on your machine.
Keep in mind that you will need to have installed HBase into your local maven repository for the in-situ cluster to work properly. That is, you will need to run:
mvn clean install -DskipTests
to ensure that maven can find the correct classpath and dependencies. Generally, the above command is just a good thing to try running first, if maven is acting oddly.
After adding a new feature a developer might want to add metrics. HBase exposes metrics using the Hadoop Metrics 2 system, so adding a new metric involves exposing that metric to the hadoop system. Unfortunately the API of metrics2 changed from hadoop 1 to hadoop 2. In order to get around this a set of interfaces and implementations have to be loaded at runtime. To get an in-depth look at the reasoning and structure of these classes you can read the blog post located here. To add a metric to an existing MBean follow the short guide below:
Inside of the source interface the corresponds to where the metrics are generated (eg MetricsMasterSource for things coming from HMaster) create new static strings for metric name and description. Then add a new method that will be called to add new reading.
Inside of the implementation of the source (eg. MetricsMasterSourceImpl in the above example) create a new histogram, counter, gauge, or stat in the init method. Then in the method that was added to the interface wire up the parameter passed in to the histogram.
Now add tests that make sure the data is correctly exported to the metrics 2 system. For this the MetricsAssertHelper is provided.
HBase moved to GIT from SVN. Until we develop our own documentation for how to contribute patches in our new GIT context, caveat the fact that we have a different branching modes and that we don't currently do the merge practice described in the following, the accumulo doc on how to contribute and develop after our move to GIT is worth a read.
If you are new to submitting patches to open source or new to submitting patches to Apache, I'd suggest you start by reading the On Contributing Patches page from Apache Commons Project. Its a nice overview that applies equally to the Apache HBase Project.
See the aforementioned Apache Commons link for how to make patches against a checked out subversion repository. Patch files can also be easily generated from Eclipse, for example by selecting "Team -> Create Patch". Patches can also be created by git diff and svn diff.
Please submit one patch-file per Jira. For example, if multiple files are changed make sure the selected resource when generating the patch is a directory. Patch files can reflect changes in multiple files.
Generating patches using git:
$ git diff --no-prefix > HBASE_XXXX.patch
Don't forget the 'no-prefix' option; and generate the diff from the root directory of project
Make sure you review Section 1.2.1.1, “Code Formatting” for code style.
The patch file should have the Apache HBase Jira ticket in the name. For example, if a patch was submitted for Foo.java
, then
a patch file called Foo_HBASE_XXXX.patch
would be acceptable where XXXX is the Apache HBase Jira number.
If you generating from a branch, then including the target branch in the filename is advised, e.g., HBASE_XXXX-0.90.patch
.
Yes, please. Please try to include unit tests with every code patch (and especially new classes and large changes). Make sure unit tests pass locally before submitting the patch.
Also, see Section 1.10.2.1, “Mockito”.
If you are creating a new unit test class, notice how other unit test classes have classification/sizing annotations at the top and a static method on the end. Be sure to include these in any new unit test files you generate. See Section 1.7, “Tests” for more on how the annotations work.
The patch should be attached to the associated Jira ticket "More Actions -> Attach Files". Make sure you click the ASF license inclusion, otherwise the patch can't be considered for inclusion.
Once attached to the ticket, click "Submit Patch" and the status of the ticket will change. Committers will review submitted patches for inclusion into the codebase. Please understand that not every patch may get committed, and that feedback will likely be provided on the patch. Fear not, though, because the Apache HBase community is helpful!
The following items are representative of common patch feedback. Your patch process will go faster if these are taken into account before submission.
See the Java coding standards for more information on coding conventions in Java.
Rather than do this...
if ( foo.equals( bar ) ) { // don't do this
... do this instead...
if (foo.equals(bar)) {
Also, rather than do this...
foo = barArray[ i ]; // don't do this
... do this instead...
foo = barArray[i];
Auto-generated code in Eclipse often looks like this...
public void readFields(DataInput arg0) throws IOException { // don't do this foo = arg0.readUTF(); // don't do this
... do this instead ...
public void readFields(DataInput di) throws IOException { foo = di.readUTF();
See the difference? 'arg0' is what Eclipse uses for arguments by default.
Keep lines less than 100 characters.
Bar bar = foo.veryLongMethodWithManyArguments(argument1, argument2, argument3, argument4, argument5, argument6, argument7, argument8, argument9); // don't do this
... do something like this instead ...
Bar bar = foo.veryLongMethodWithManyArguments( argument1, argument2, argument3,argument4, argument5, argument6, argument7, argument8, argument9);
This happens more than people would imagine.
Bar bar = foo.getBar(); <--- imagine there's an extra space(s) after the semicolon instead of a line break.
Make sure there's a line-break after the end of your code, and also avoid lines that have nothing but whitespace.
In 0.96, HBase moved to protobufs. The below section on Writables applies to 0.94.x and previous, not to 0.96 and beyond.
Every class returned by RegionServers must implement Writable
. If you
are creating a new class that needs to implement this interface, don't forget the default constructor.
This is also a very common feedback item. Don't forget Javadoc!
Javadoc warnings are checked during precommit. If the precommit tool gives you a '-1', please fix the javadoc issue. Your patch won't be committed if it adds such warnings.
Findbugs is used to detect common bugs pattern. As Javadoc, it is checked during the precommit build up on Apache's Jenkins, and as with Javadoc, please fix them. You can run findbugs locally with 'mvn findbugs:findbugs': it will generate the findbugs files locally. Sometimes, you may have to write code smarter than Findbugs. You can annotate your code to tell Findbugs you know what you're doing, by annotating your class with:
@edu.umd.cs.findbugs.annotations.SuppressWarnings( value="HE_EQUALS_USE_HASHCODE", justification="I know what I'm doing")
Note that we're using the apache licensed version of the annotations.
Don't just leave the @param arguments the way your IDE generated them. Don't do this...
/** * * @param bar <---- don't do this!!!! * @return <---- or this!!!! */ public Foo getFoo(Bar bar);
... either add something descriptive to the @param and @return lines, or just remove them. But the preference is to add something descriptive and useful.
If you submit a patch for one thing, don't do auto-reformatting or unrelated reformatting of code on a completely different area of code.
Likewise, don't add unrelated cleanup or refactorings outside the scope of your Jira.
Sometimes committers ask for changes for a patch. After incorporating the suggested/requested changes, follow the following process to submit the patch again.
Do not delete the old patch file
version your new patch file using a simple scheme like this:
HBASE-{jira number}-{version}.patch
e.g:
HBASE_XXXX-v2.patch
'Cancel Patch' on JIRA.. bug status will change back to Open
Attach new patch file (e.g. HBASE_XXXX-v2.patch) using 'Files --> Attach'
Click on 'Submit Patch'. Now the bug status will say 'Patch Available'.
Committers will review the patch. Rinse and repeat as many times as needed :-)
At times you may want to break a big change into mulitple patches. Here is a sample work-flow using git
patch 1:
$ git diff --no-prefix > HBASE_XXXX-1.patch
patch 2:
create a new git branch
$ git checkout -b my_branch
save your work
$ git add file1 file2
$ git commit -am 'saved after HBASE_XXXX-1.patch'
now you have your own branch, that is different from remote master branch
make more changes...
create second patch
$ git diff --no-prefix > HBASE_XXXX-2.patch
Larger patches should go through ReviewBoard.
For more information on how to use ReviewBoard, see the ReviewBoard documentation.
New committers are encouraged to first read Apache's generic committer documentation:
HBase committers should, as often as possible, attempt to review patches submitted by others. Ideally every submitted patch will get reviewed by a committer within a few days. If a committer reviews a patch they've not authored, and believe it to be of sufficient quality, then they can commit the patch, otherwise the patch should be cancelled with a clear explanation for why it was rejected.
The list of submitted patches is in the HBase Review Queue. This is ordered by time of last modification. Committers should scan the list from top-to-bottom, looking for patches that they feel qualified to review and possibly commit.
For non-trivial changes, it is required to get another committer to review your own patches before commit. Use "Submit Patch" like other contributors, and then wait for a "+1" from another committer before committing.
Patches should be rejected which do not adhere to the guidelines in HowToContribute and to the code review checklist. Committers should always be polite to contributors and try to instruct and encourage them to contribute better patches. If a committer wishes to improve an unacceptable patch, then it should first be rejected, and a new patch should be attached by the committer for review.
Committers commit patches.
When you commit a patch, please:
Include the Jira issue id in the commit message, along with a short description of the change and the name of the contributor if it is not you. Be sure to get the issue id right, as this causes Jira to link to the change in Subversion (use the issue's "All" tab to see these).
Resolve the issue as fixed, thanking the contributor. Always set the "Fix Version" at this point, but please only set a single fix version, the earliest release in which the change will appear.
If a committer commits a patch it is their responsibility to make sure it passes the test suite. It is helpful if contributors keep an eye out that their patch does not break the hbase build and/or tests but ultimately, a contributor cannot be expected to be up on the particular vagaries and interconnections that occur in a project like hbase. A committer should.
In the thread HBase, mail # dev - ANNOUNCEMENT: Git Migration In Progress (WAS => Re: Git Migration), it was agreed on the following patch flow
Develop and commit the patch against trunk/master first.
Try to cherry-pick the patch when backporting if possible.
If this does not work, manually commit the patch to the branch.
Committers should hang out in the #hbase room on irc.freenode.net for real-time discussions. However any substantive discussion (as with any off-list project-related discussion) should be re-iterated in Jira or on the developer list.
Misspellings and/or bad grammar is preferable to the disruption a JIRA comment edit causes: See the discussion at Re:(HBASE-451) Remove HTableDescriptor from HRegionInfo