Support opensearch-sql:run and update developer_guide doc (opensearch-project#1099)

Support opensearch-sql:run
Update developer_guide doc. add prometheus and filesystem description.
Add .java-version to .gitignore

Signed-off-by: Peng Huo <[email protected]>

Author: penghuo

.gitignore

@@ -44,3 +44,5 @@ gen
 /artifacts/
 /.pid.lock
 /.prom.pid.lock
+
+.java-version

DEVELOPER_GUIDE.rst

@@ -141,6 +141,8 @@ The plugin codebase is in standard layout of Gradle project::
    ├── core
    ├── doctest
    ├── opensearch
+   ├── filesystem
+   ├── prometheus
    ├── integ-test
    ├── legacy
    ├── plugin
@@ -159,6 +161,8 @@ Here are sub-folders (Gradle modules) for plugin source code:
 - ``ppl``: PPL language processor.
 - ``core``: core query engine.
 - ``opensearch``: OpenSearch storage engine.
+- ``prometheus``: Prometheus storage engine.
+- ``filesystem``: File System storage engine (in development).
 - ``protocol``: request/response protocol formatter.
 - ``common``: common util code.
 - ``integ-test``: integration and comparison test.

plugin/build.gradle

@@ -30,6 +30,7 @@ plugins {
 }
 
 apply plugin: 'opensearch.pluginzip'
+apply plugin: 'opensearch.rest-test'
 
 ext {
     projectSubstitutions = [:]
@@ -226,3 +227,19 @@ afterEvaluate {
         }
     }
 }
+
+testClusters.integTest {
+    plugin(project.tasks.bundlePlugin.archiveFile)
+
+    // debug with command, ./gradlew opensearch-sql:run -DdebugJVM. --debug-jvm does not work with keystore.
+    if (System.getProperty("debugJVM") != null) {
+        jvmArgs '-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:5005'
+    }
+
+    // add customized keystore
+    keystore 'plugins.query.federation.datasources.config', new File("$projectDir/src/test/resources/", 'datasources.json')
+}
+
+run {
+    useCluster testClusters.integTest
+}