Add extra logs and debugging features

* New DEBUG environment variable enables `set -x` in shell scripts for
  extra verbose output for debugging custom cron scripts and to assist
  with development of the core scripts.
* Verify if we can find the Nextcloud container on start up. Fail if
  not.
* Print information about how we will search for Nextcloud on start up.
* During cron task execution, the ID of the Nextcloud container is
  printed, if found.

README.md

@@ -77,6 +77,10 @@ how this all works.
   in the tasks being executed using the Nextcloud container's running user. Specifically, the
   `--user` option will *not* be provided to the `docker exec` command.
 
+* `DEBUG`<br>
+  Enables more verbose logging in core scripts. Useful only for development. To get more verbose
+  output in your own custom cron scripts, use `set -x` in the actual script.
+
 ## Container Health
 
 If you do `docker-compose ps`, you will see the active health of the container. The following logic

scripts/cron-tasks.sh

@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
 set -e
+[[ ! -z "$DEBUG" ]] && set -x
 
 echo "-------------------------------------------------------------"
 echo " Executing Cron Tasks: $(date)"
@@ -20,6 +21,8 @@ if [[ -z "$containerId" ]]; then
     exit 1
 fi
 
+echo "> Nextcloud Container ID: ${containerId}"
+
 # Loop through all shell scripts and execute the contents of those scripts in the Nextcloud
 # container. It's done this way so that the user may mount more scripts to be executed in addition
 # to the default ones.

scripts/entrypoint.sh

@@ -1,11 +1,29 @@
 #!/usr/bin/env bash
 set -e
+[[ ! -z "$DEBUG" ]] && set -x
 
 if [[ -z "$NEXTCLOUD_CONTAINER_NAME" ]]; then
     echo "NEXTCLOUD_CONTAINER_NAME is a required variable"
     exit 1
 fi
 
+# Print info about how we will look for Nextcloud
+if [[ -n "$NEXTCLOUD_PROJECT_NAME" ]]; then
+    echo "Will search for Nexcloud container as a Docker Compose service"
+    echo "Project: $NEXTCLOUD_PROJECT_NAME, Service: $NEXTCLOUD_CONTAINER_NAME"
+else
+    echo "Container Name: $NEXTCLOUD_CONTAINER_NAME"
+fi
+
+# Do an initial search for the container to rule out any configuration problems
+containerId="$(/find-container.sh)"
+if [[ -z "$containerId" ]]; then
+    echo "ERROR: Unable to find the Nextcloud container"
+    exit 1
+else
+    echo "Found Nextcloud container with ID $containerId"
+fi
+
 echo "*/$NEXTCLOUD_CRON_MINUTE_INTERVAL * * * * /cron-tasks.sh" \
     > /var/spool/cron/crontabs/root