206 lines
12 KiB
Plaintext
206 lines
12 KiB
Plaintext
// Do not edit this file (e.g. go instead to src/main/asciidoc)
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image::https://api.travis-ci.org/spring-cloud/spring-cloud-sleuth.svg?branch=master[Build Status, link=https://travis-ci.org/spring-cloud/spring-cloud-sleuth]
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=== Terminology
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Spring Cloud Sleuth borrows http://research.google.com/pubs/pub36356.html[Dapper's] terminology.
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*Span:* The basic unit of work. For example, sending an RPC is a new span, as is sending a response to an RPC. Span's are identified by a unique 64-bit ID for the span and another 64-bit ID for the trace the span is a part of. Spans also have other data, such as descriptions, key-value annotations, the ID of the span that caused them, and process ID's (normally IP address).
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Spans are started and stopped, and they keep track of their timing information. Once you create a span, you must stop it at some point in the future.
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*Trace:* A set of spans forming a tree-like structure. For example, if you are running a distributed big-data store, a trace might be formed by a put request.
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== Features
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* Adds trace and span ids to the Slf4J MDC, so you can extract all the logs from a given trace or span in a log aggregator. Example configuration:
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+
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[source,yaml]
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----
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logging:
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pattern:
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console: '%d{yyyy-MM-dd HH:mm:ss.SSS} [trace=%X{X-Trace-Id:-},span=%X{X-Span-Id:-}] [%15.15t] %-40.40logger{39}: %m%n'
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----
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+
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(notice the `%X` entries from the MDC).
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* Optionally log span data in JSON format for harvesting in a log aggregator (set `spring.sleuth.log.json.enabled=true`).
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* Provides an abstraction over common distributed tracing data models: traces, spans (forming a DAG), annotations, key-value annotations. Loosely based on HTrace, but Zipkin (Dapper) compatible.
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* Instruments common ingress and egress points from Spring applications (servlet filter, rest template, scheduled actions, message channels, zuul filters, feign client).
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* If `spring-cloud-sleuth-zipkin` then the app will generate and collect Zipkin-compatible traces (using Brave). By default it sends them via Thrift to a Zipkin collector service on localhost (port 9410). Configure the location of the service using `spring.zipkin.[host,port]`.
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== Running the samples
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1. Optionally run https://github.com/openzipkin/zipkin[Zipkin], e.g. via docker compose (there's a `docker-compose.yml` in https://github.com/spring-cloud-incubator/spring-cloud-sleuth[Spring Cloud Sleuth], or in https://github.com/openzipkin/docker-zipkin[Docker Zipkin]
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7. Run the zipkin sample application (and set `sample.zipkin.enabled=false` if you have no collector running)
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8. Hit `http://localhost:3380`, `http://localhost:3380/call`, `http://localhost:3380/async` for some interesting sample traces (the app callas back to itself).
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9. Goto `http://localhost:8082` for zipkin web (8080 if running locally from source, the host is the docker host, so if you are using boot2docker it will be different)
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WARNING: The docker images for zipkin are old and don't work very well (the UI in particular). Zipkin is in a state of flux, but it should settle down soon when there is an actual release. Best results actually come from building from source and running the jar files (the query and collector services need command line arguments, so check the zipkin README for updates).
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NOTE: You can see the zipkin spans without the UI (in logs) if you run the sample with `sample.zipkin.enabled=false`.
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There are a few samples with slightly different features:
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* `spring-cloud-sleuth-sample`: vanilla (no zipkin) web app that calls back to itself on various endpoints ("/", "/call", "/async")
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* `spring-cloud-sleuth-sample-zipkin`: same as vanilla sample but with zipkin
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* `spring-cloud-sleuth-sample-messaging`: a Spring Integration application with two HTTP endpoints ("/" and "/xform")
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* `spring-cloud-sleuth-sample-ribbon`: two endpoints ("/" and "/call") that make calls to the "zipkin" sample via Ribbon. Also has `@EnableZUulProxy" so if the other samples are running they are proxied at "/messaging", "/zipkin", "/vanilla" (see "/routes" for a list).
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The Ribbon sample makes an interesting demo or playground for learning about zipkin. In the screenshot below you can see a trace with 3 spans - it starts in the "testSleuthRibbon" app and crosses to "testSleuthMessaging" for the next 2 spans.
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image::https://raw.githubusercontent.com/spring-cloud/spring-cloud-sleuth/master/docs/src/main/asciidoc/images/zipkin-trace-screenshot.png[Eample Zipkin Screenshot]
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> The fact that the first trace in says "testSleuthMessaging" seems to be a bug in the UI (it has some annotations from that service, but it originates in the "testSleuthRibbon" service).
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== Building
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:jdkversion: 1.7
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=== Basic Compile and Test
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To build the source you will need to install
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http://maven.apache.org/run-maven/index.html[Apache Maven] v3.0.6 or above and JDK {jdkversion}.
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Spring Cloud uses Maven for most build-related activities, and you
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should be able to get off the ground quite quickly by cloning the
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project you are interested in and typing
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----
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$ mvn install -s .settings.xml
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----
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NOTE: You may need to increase the amount of memory available to Maven by setting
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a `MAVEN_OPTS` environment variable with the value `-Xmx512m -XX:MaxPermSize=128m`
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The `.settings.xml` is only required the first time (or after updates
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to dependencies). It is there to provide repository declarations so
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that those do not need to be hard coded in the project poms.
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For hints on how to build the project look in `.travis.yml` if there
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is one. There should be a "script" and maybe "install" command. Also
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look at the "services" section to see if any services need to be
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running locally (e.g. mongo or rabbit). Ignore the git-related bits
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that you might find in "before_install" since they will be able git
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credentials and you already have those.
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If you need mongo, rabbit or redis, see the README in the https://github.com/spring-cloud-samples/scripts[scripts
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demo repository] for
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instructions. For example consider using the "fig.yml" with
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http://www.fig.sh/[Fig] to run them in Docker containers.
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=== Documentation
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The spring-cloud-build module has a "docs" profile, and if you switch
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that on it will try to build asciidoc sources from
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`src/main/asciidoc`. As part of that process it will look for a
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`README.adoc` and process it by loading all the includes, but not
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parsing or rendering it, just copying it to `${main.basedir}`
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(defaults to `${basedir}`, i.e. the root of the project). If there are
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any changes in the README it will then show up after a Maven build as
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a modified file in the correct place. Just commit it and push the change.
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=== Working with the code
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If you don't have an IDE preference we would recommend that you use
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http://www.springsource.com/developer/sts[Spring Tools Suite] or
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http://eclipse.org[Eclipse] when working with the code. We use the
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http://eclipse.org/m2e/[m2eclipe] eclipse plugin for maven support. Other IDEs and tools
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should also work without issue.
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==== Importing into eclipse with m2eclipse
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We recommend the http://eclipse.org/m2e/[m2eclipe] eclipse plugin when working with
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eclipse. If you don't already have m2eclipse installed it is available from the "eclipse
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marketplace".
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Once the projects are imported into Eclipse you will also need to tell m2eclipse
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to use the `.settings.xml` file for the projects. If you do not do this you may
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see errors many different errors related to the POMs in the projects.
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Open your Eclipse preferences, expand the Maven preferences, and select User Settings.
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In the User Settings field click Browse and navigate to the Spring Cloud project you
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imported selecting the `.settings.xml` file in that project. Click Apply and then OK to
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save the preference changes.
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==== Importing into eclipse without m2eclipse
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If you prefer not to use m2eclipse you can generate eclipse project metadata using the
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following command:
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[indent=0]
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----
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$ mvn eclipse:eclipse
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----
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The generated eclipse projects can be imported by selecting `import existing projects`
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from the `file` menu.
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==== Adding Project Lombok Agent
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Spring Cloud uses Spring Cloud uses http://projectlombok.org/features/index.html[Project Lombok]
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to generate getters and setters etc. Compiling from the command line this
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shouldn't cause any problems, but in an IDE you need to add an agent
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to the JVM. Full instructions can be found in the Lombok website. The
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sign that you need to do this is a lot of compiler errors to do with
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missing methods and fields, e.g.
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[indent=0]
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----
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The method getInitialStatus() is undefined for the type EurekaInstanceConfigBean EurekaDiscoveryClientConfiguration.java /spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/eureka line 120 Java Problem
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The method getInitialStatus() is undefined for the type EurekaInstanceConfigBean EurekaDiscoveryClientConfiguration.java /spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/eureka line 121 Java Problem
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The method setNonSecurePort(int) is undefined for the type EurekaInstanceConfigBean EurekaDiscoveryClientConfiguration.java /spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/eureka line 112 Java Problem
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The type EurekaInstanceConfigBean.IdentifyingDataCenterInfo must implement the inherited abstract method DataCenterInfo.getName() EurekaInstanceConfigBean.java /spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/eureka line 131 Java Problem
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The method getId() is undefined for the type ProxyRouteLocator.ProxyRouteSpec PreDecorationFilter.java /spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/zuul/filters/pre line 60 Java Problem
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The method getLocation() is undefined for the type ProxyRouteLocator.ProxyRouteSpec PreDecorationFilter.java /spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/zuul/filters/pre line 55 Java Problem
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----
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==== Importing into other IDEs
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Maven is well supported by most Java IDEs. Refer to you vendor documentation.
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== Contributing
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Spring Cloud is released under the non-restrictive Apache 2.0 license,
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and follows a very standard Github development process, using Github
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tracker for issues and merging pull requests into master. If you want
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to contribute even something trivial please do not hesitate, but
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follow the guidelines below.
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=== Sign the Contributor License Agreement
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Before we accept a non-trivial patch or pull request we will need you to sign the
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https://support.springsource.com/spring_committer_signup[contributor's agreement].
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Signing the contributor's agreement does not grant anyone commit rights to the main
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repository, but it does mean that we can accept your contributions, and you will get an
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author credit if we do. Active contributors might be asked to join the core team, and
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given the ability to merge pull requests.
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=== Code Conventions and Housekeeping
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None of these is essential for a pull request, but they will all help. They can also be
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added after the original pull request but before a merge.
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* Use the Spring Framework code format conventions. If you use Eclipse
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you can import formatter settings using the
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`eclipse-code-formatter.xml` file from the
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https://github.com/spring-cloud/build/tree/master/eclipse-coding-conventions.xml[Spring
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Cloud Build] project. If using IntelliJ, you can use the
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http://plugins.jetbrains.com/plugin/6546[Eclipse Code Formatter
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Plugin] to import the same file.
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* Make sure all new `.java` files to have a simple Javadoc class comment with at least an
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`@author` tag identifying you, and preferably at least a paragraph on what the class is
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for.
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* Add the ASF license header comment to all new `.java` files (copy from existing files
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in the project)
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* Add yourself as an `@author` to the .java files that you modify substantially (more
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than cosmetic changes).
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* Add some Javadocs and, if you change the namespace, some XSD doc elements.
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* A few unit tests would help a lot as well -- someone has to do it.
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* If no-one else is using your branch, please rebase it against the current master (or
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other target branch in the main project).
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* When writing a commit message please follow http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html[these conventions],
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if you are fixing an existing issue please add `Fixes gh-XXXX` at the end of the commit
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message (where XXXX is the issue number). |