[Misc] Added comments for the DOOD use case

xwiki-platform-core/xwiki-platform-test/xwiki-platform-test-docker/src/main/java/org/xwiki/test/docker/junit5/AbstractContainerExecutor.java

@@ -72,8 +72,12 @@ protected void start(GenericContainer container, TestConfiguration testConfigura
     protected void mountFromHostToContainer(GenericContainer container, String sourceDirectory,
         String targetDirectory)
     {
-        // File mounting is awfully slow on Mac OSX. For example starting Tomcat with XWiki mounted takes
+        // Note 1: File mounting is awfully slow on Mac OSX. For example starting Tomcat with XWiki mounted takes
         // 45s+, while doing a COPY first and then starting Tomcat takes 8s (+5s for the copy).
+        // Note 2: For the DOOD use case, we also do the copy instead of the volume mounting since that would require
+        // to have the sourceDirectory path mounted from the host and this would put and leave files on the host which
+        // would not work with parallel executions (think about multiple CI jobs executing in parallel on the same host)
+        // and would also not be clean.
         String osName = System.getProperty("os.name").toLowerCase();
         if (IN_A_CONTAINER || osName.startsWith("mac os x")) {
             MountableFile mountableDirectory = MountableFile.forHostPath(sourceDirectory);

xwiki-platform-core/xwiki-platform-test/xwiki-platform-test-docker/src/main/java/org/xwiki/test/docker/junit5/database/DatabaseContainerExecutor.java

@@ -105,11 +105,7 @@ private void startMySQLContainer(JdbcDatabaseContainer databaseContainer, TestCo
             .withUsername(DBUSERNAME)
             .withPassword(DBPASSWORD);
 
-        if (testConfiguration.isDatabaseDataSaved()) {
-            // This allows re-running the test with the database already provisioned without having to redo
-            // the provisioning. Running "mvn clean" will remove the database data.
-            databaseContainer.withFileSystemBind("./target/mysql", "/var/lib/mysql");
-        }
+        mountDatabaseDataIfNeeded(databaseContainer, "./target/mysql", "/var/lib/mysql", testConfiguration);
 
         // Note: the "explicit-defaults-for-timestamp" parameter has been introduced in MySQL 5.6.6+ only and using it
         // in older versions make MySQL fail to start.
@@ -176,11 +172,8 @@ private void startPostgreSQLContainer(TestConfiguration testConfiguration)
             .withUsername(DBUSERNAME)
             .withPassword(DBPASSWORD);
 
-        if (testConfiguration.isDatabaseDataSaved()) {
-            // This allows re-running the test with the database already provisioned without having to redo
-            // the provisioning. Running "mvn clean" will remove the database data.
-            databaseContainer.withFileSystemBind("./target/postgres", "/var/lib/postgresql/data");
-        }
+        mountDatabaseDataIfNeeded(databaseContainer, "./target/postgres", "/var/lib/postgresql/data",
+            testConfiguration);
 
         databaseContainer.addEnv("POSTGRES_ROOT_PASSWORD", DBPASSWORD);
         databaseContainer.addEnv("POSTGRES_INITDB_ARGS", "--encoding=UTF8");
@@ -188,6 +181,19 @@ private void startPostgreSQLContainer(TestConfiguration testConfiguration)
         startDatabaseContainer(databaseContainer, 5432, testConfiguration);
     }
 
+    private void mountDatabaseDataIfNeeded(JdbcDatabaseContainer databaseContainer, String hostPath,
+        String containerPath, TestConfiguration testConfiguration)
+    {
+        if (testConfiguration.isDatabaseDataSaved()) {
+            // Note 1: This allows re-running the test with the database already provisioned without having to redo
+            // the provisioning. Running "mvn clean" will remove the database data.
+            // Note 2: This won't work in the DOOD use case. For that to work we would need to copy the data instead
+            // of mounting the volume but the time to do that would be counter productive and cost in execution time
+            // when the goal is to win time...
+            databaseContainer.withFileSystemBind(hostPath, containerPath);
+        }
+    }
+
     private void startOracleContainer(TestConfiguration testConfiguration)
     {
         JdbcDatabaseContainer databaseContainer;

xwiki-platform-core/xwiki-platform-test/xwiki-platform-test-docker/src/main/java/org/xwiki/test/docker/junit5/servletEngine/ServletContainerExecutor.java

@@ -157,6 +157,8 @@ private void startContainer()
                     .forStatusCode(200).withStartupTimeout(Duration.of(480, SECONDS)));
 
         if (this.testConfiguration.isOffline()) {
+            // Note: This won't work in the DOOD use case. For that to work we would need to copy the data instead
+            // of mounting the volume but the time it would take would be too costly.
             String repoLocation = this.repositoryResolver.getSession().getLocalRepository().getBasedir().toString();
             this.servletContainer.withFileSystemBind(repoLocation, "/root/.m2/repository");
         }
@@ -165,9 +167,13 @@ private void startContainer()
         // inside the container
         String cloverDatabase = System.getProperty("maven.clover.cloverDatabase");
         if (cloverDatabase != null) {
-            // Note: The Clover instrumentation puts the full path to the clover database location inside the java
+            // Note 1: The Clover instrumentation puts the full path to the clover database location inside the java
             // source files which execute inside the docker container. Thus we need to make that exact same full path
             // available inside the container...
+            // Note 2: For this to work in DOOD (Docker Outside Of Docker), the container in which this code is
+            // running will need to have mapped the volume pointed to by the "maven.clover.cloverDatabase" system
+            // property. It'll also need to make sure that it's removed before the build executes so that it doesn't
+            // execute with Clover data from a previous run.
             this.servletContainer.withFileSystemBind(cloverDatabase, cloverDatabase);
         }