public void proceedCommandExecution() { // Steps are executed such that: // a) all logic before the command runs is idempotent // b) the command is the last action in the step // This allows for recovery after a crash at any point during command execution. log.debug("Proceeding with execution of RemoveSnapshotSingleDiskLiveCommand"); if (getParameters().getCommandStep() == null) { getParameters().setCommandStep(getInitialMergeStepForImage(getParameters().getImageId())); getParameters().setChildCommands(new HashMap<RemoveSnapshotSingleDiskLiveStep, Guid>()); } // Upon recovery or after invoking a new child command, our map may be missing an entry syncChildCommandList(); Guid currentChildId = getCurrentChildId(); VdcReturnValueBase vdcReturnValue = null; if (currentChildId != null) { switch (CommandCoordinatorUtil.getCommandStatus(currentChildId)) { case ACTIVE: case NOT_STARTED: log.info( "Waiting on Live Merge command step '{}' to complete", getParameters().getCommandStep()); return; case SUCCEEDED: CommandEntity cmdEntity = CommandCoordinatorUtil.getCommandEntity(currentChildId); if (cmdEntity.isCallbackEnabled() && !cmdEntity.isCallbackNotified()) { log.info( "Waiting on Live Merge command step '{}' to finalize", getParameters().getCommandStep()); return; } vdcReturnValue = CommandCoordinatorUtil.getCommandReturnValue(currentChildId); if (vdcReturnValue != null && vdcReturnValue.getSucceeded()) { log.debug("Child command '{}' succeeded", getParameters().getCommandStep()); getParameters().setCommandStep(getParameters().getNextCommandStep()); break; } else { log.error( "Child command '{}' failed: {}", getParameters().getCommandStep(), (vdcReturnValue != null ? vdcReturnValue.getExecuteFailedMessages() : "null return value")); setCommandStatus(CommandStatus.FAILED); return; } case FAILED: case FAILED_RESTARTED: log.error("Failed child command status for step '{}'", getParameters().getCommandStep()); setCommandStatus(CommandStatus.FAILED); return; case UNKNOWN: log.error("Unknown child command status for step '{}'", getParameters().getCommandStep()); setCommandStatus(CommandStatus.FAILED); return; } } log.info("Executing Live Merge command step '{}'", getParameters().getCommandStep()); Pair<VdcActionType, ? extends VdcActionParametersBase> nextCommand = null; switch (getParameters().getCommandStep()) { case EXTEND: nextCommand = new Pair<>(VdcActionType.MergeExtend, buildMergeParameters()); getParameters().setNextCommandStep(RemoveSnapshotSingleDiskLiveStep.MERGE); break; case MERGE: nextCommand = new Pair<>(VdcActionType.Merge, buildMergeParameters()); getParameters().setNextCommandStep(RemoveSnapshotSingleDiskLiveStep.MERGE_STATUS); break; case MERGE_STATUS: getParameters().setMergeCommandComplete(true); nextCommand = new Pair<>(VdcActionType.MergeStatus, buildMergeParameters()); getParameters().setNextCommandStep(RemoveSnapshotSingleDiskLiveStep.DESTROY_IMAGE); break; case DESTROY_IMAGE: if (vdcReturnValue != null) { getParameters() .setMergeStatusReturnValue( (MergeStatusReturnValue) vdcReturnValue.getActionReturnValue()); } else if (getParameters().getMergeStatusReturnValue() == null) { // If the images were already merged, just add the orphaned image getParameters().setMergeStatusReturnValue(synthesizeMergeStatusReturnValue()); } nextCommand = new Pair<>(VdcActionType.DestroyImage, buildDestroyImageParameters()); getParameters().setNextCommandStep(RemoveSnapshotSingleDiskLiveStep.COMPLETE); break; case COMPLETE: getParameters().setDestroyImageCommandComplete(true); setCommandStatus(CommandStatus.SUCCEEDED); break; } persistCommand(getParameters().getParentCommand(), true); if (nextCommand != null) { CommandCoordinatorUtil.executeAsyncCommand( nextCommand.getFirst(), nextCommand.getSecond(), cloneContextAndDetachFromParent()); // Add the child, but wait, it's a race! child will start, task may spawn, get polled, and we // won't have the child id } }