Include lastException as cause when docker-compose up fails (#732)

Include lastException as cause when docker-compose up fails

Author: ash211

changelog/@unreleased/pr-732.v2.yml

@@ -0,0 +1,5 @@
+type: improvement
+improvement:
+  description: Include lastException as cause when docker-compose up fails
+  links:
+  - https://github.com/palantir/docker-compose-rule/pull/732

docker-compose-rule-core/src/main/java/com/palantir/docker/compose/execution/ConflictingContainerRemovingDockerCompose.java

@@ -46,11 +46,13 @@ public ConflictingContainerRemovingDockerCompose(DockerCompose dockerCompose, Do
 
     @Override
     public void up() throws IOException, InterruptedException {
+        DockerExecutionException lastException = null;
         for (int currRetryAttempt = 0; currRetryAttempt <= retryAttempts; currRetryAttempt++) {
             try {
                 getDockerCompose().up();
                 return;
             } catch (DockerExecutionException e) {
+                lastException = e;
                 Set<String> conflictingContainerNames = getConflictingContainerNames(e.getMessage());
                 if (conflictingContainerNames.isEmpty()) {
                     // failed due to reason other than conflicting containers, so re-throw
@@ -66,7 +68,7 @@ public void up() throws IOException, InterruptedException {
             }
         }
 
-        throw new DockerExecutionException("docker-compose up failed");
+        throw new DockerExecutionException("docker-compose up failed", lastException);
     }
 
     private void removeContainers(Collection<String> containerNames) throws IOException, InterruptedException {

docker-compose-rule-core/src/main/java/com/palantir/docker/compose/execution/DockerExecutionException.java

@@ -21,4 +21,8 @@ public DockerExecutionException() {}
     public DockerExecutionException(String message) {
         super(message);
     }
+
+    public DockerExecutionException(String message, Throwable cause) {
+        super(message, cause);
+    }
 }