Follow these steps to build and run ERDDAP™ for local development using Maven and the Jetty 12 Servlet Container. This workflow streamlines the iterative development process for ERDDAP (re-compiling Java source code and redeploying static assets).
Upon completion, ERDDAP™ will be available at http://localhost:8080/erddap.
First, install Maven following these directions.
Once complete, you should have the mvn command available on your command prompt. From the root directory of your ERDDAP™ clone, run mvn validate to ensure everything is working:
mvn validate
These steps will download some additional files not included in the ERDDAP™ GitHub repository, create local directories for ERDDAP's "content" (./content) and "bigParentDirectory" (./data) directories, compile the ERDDAP™ code, and finally create an 'exploded' Java WAR directory to use to run ERDDAP™. There is also a pre-configured version of ERDDAP's setup.xml file that will be copied to the ./content directory to allow ERDDAP™ to start.
mvn compile
mvn war:exploded
ERDDAP™ can be run in Jetty with the following command:
MAVEN_OPTS="-Xms4096m -Xmx4096m" mvn jetty:run -DerddapContentDirectory=development/jetty/config
Access ERDDAP™ at: http://localhost:8080/erddap.
Note: the -Xms and -Xmx flags assign memory to the Java process running Jetty, and must be specified using the MAVEN_OPTS parameter. 4096M (or 4G) is sufficient for running ERDDAP™ in development mode, however you can tune these values according to your preferences (to limit memory to 2G, use instead: MAVEN_OPTS="-Xms2048m -Xmx2048m" mvn jetty:run -DerddapContentDirectory=development/jetty/config).
Maven and Jetty offers advantages over Tomcat for iterative development, shortening the dev/test cycle and improving developer productivity.
The following table is a short list of Maven commands describing the workflow to update source files and redeploy ERDDAP™ in Jetty. Typically, you would run all three in succession to view your changes.
| Command | Description |
|---|---|
mvn compile |
Compiles ERDDAP™ Java classes to ./target/classes. This can be skipped if you haven't modified any Java source files. |
mvn war:exploded |
Creates an 'exploded' ERDDAP™ WAR file in ./target/${project.build.finalName} (currently ./target/ERDDAP-2.24-SNAPSHOT) to run ERDDAP™ in Jetty, including Java classes that were compiled to ./target/classes via mvn compile. This can be run without the mvn compile step if only static (non-Java) files have been modified. |
CR (carriage return) |
Type a CR (carriage return) in the console running the Jetty process (mvn jetty:run) to reload the ERDDAP™ web application (most likely only necessary for changes to compiled Java classes). |
Note: both the mvn compile and mvn war:exploded commands must be run before launching ERDDAP™ via mvn jetty:run, or after making code changes and reloading ERDDAP™ via CR (carriage return) in the Jetty console, due to some ERDDAP™ filesystem lookups in utility classes like File2.java. These require ERDDAP™ to be run in Jetty in 'exploded WAR' format so that the WEB-INF directory is in the path.
Removing these lookups from ERDDAP™ would allow leveraging Jetty features such as auto-redploying ERDDAP™ on source code changes using the scan parameter, as described in the mvn jetty:run documentation, and enable running ERDDAP™ from source with only a single command:
MAVEN_OPTS="-Xms4096m -Xmx4096m" mvn jetty:run -DerddapContentDirectory=development/jetty/config
Some other useful commands for developing ERDDAP™ with Maven (not needed for development workflow):
| Command | Description |
|---|---|
mvn clean |
Deletes the ${project.build.directory} (i.e. ./target) directory. |
mvn resources:resources |
Copies ERDDAP™ static files from ./WEB-INF/classes to ./target/classes. |
mvn package |
Builds ./target/${project.build.finalName}.war (currently /target/ERDDAP-2.24-SNAPSHOT.war) distributable ERDDAP™ WAR (suitable for deployment to Tomcat if desired). |