Add a file in volume when volume is initialized

README.md

@@ -32,8 +32,11 @@ sync:
   volumes:
     - geoserver_datadir:/var/local/data:rw
 ```
+If `WATCH_FILE` environment is not set, volume will only be bootstraped from
+remote git repository. Note that entrypoint will stop just after volume
+bootstrap so you should configure container restart policy.
 
-Required environment:
+Required environment for watching:
  * `WATCH_FILE`: file to watch (path relative to volume root)
  * `GIT_COMMIT_MESSAGE`: string or expression evaluated in the volume to provide a commit message
  * `GIT_USERNAME`: git username for commit
@@ -46,6 +49,20 @@ To push to a repository, these additional variables are required:
 Optional environment:
  * `REMOTE_BRANCH`: Remote branch to use. Defaults to master.
  * `FORCE_CLONE`: Delete volume content before cloning remote repository
+ * `INITIALIZED_FILE_FLAG`: If set, a file will be created after initialisation
+   called INITIALIZED_FILE_FLAG. During initialisation, this file will be
+   deleted. This should be a relative path to volume root. This file can be used
+   to avoid other containers from starting during initialisation of the volume.
+
+Example of script that wait for a `initialised` file to be created:
+```bash
+until ls /mnt/volume/initialised; do
+  echo waiting for volume initialisation;
+  sleep 1;
+done;
+```
+This kind of script can be launched before main entrypoint of other
+containers.
 
 To use SSH authentication to access remote repository, one of following
 variables must be set:

scripts/entrypoint.sh

@@ -1,5 +1,11 @@
 #!/bin/bash
 
+# Remove flag file during initialisation
+if [ -n $INITIALIZED_FILE_FLAG ] && [ -f $INITIALIZED_FILE_FLAG ]; then
+  echo "rm -f $INITIALIZED_FILE_FLAG..."
+  rm -f $INITIALIZED_FILE_FLAG
+fi
+
 # set name and email to use for commits made by this container
 git config --global user.email "$GIT_EMAIL"
 git config --global user.name "$GIT_USERNAME"
@@ -64,5 +70,14 @@ if [ -n "$REMOTE_NAME" ] && [ -n "$REMOTE_URL" ]; then
   git clean -xdf
 fi
 
-# execute CMD
-exec "$@"
+# Add a file to mark volume as initialized
+if [ -n $INITIALIZED_FILE_FLAG ]; then
+  pwd
+  echo "touch $INITIALIZED_FILE_FLAG"
+  touch $INITIALIZED_FILE_FLAG
+fi
+
+# Launch inotify to watch $WATCH_FILE if configured
+if [ -n "$WATCH_FILE" ]; then
+  exec "$@"
+fi

scripts/run.sh

@@ -21,13 +21,23 @@ do
     # set up watches:
     inotifywait -e modify $WATCH_FILE
 
+    # Temporary remove flag file to avoid commit of this file
+    if [ -n $INITIALIZED_FILE_FLAG ] && [ -f $INITIALIZED_FILE_FLAG ]; then
+      rm -f $INITIALIZED_FILE_FLAG
+    fi
+
     # commit all files from current dir:
     git add --all .
 
     # commit with custom message:
     msg=`eval $GIT_COMMIT_MESSAGE`
     git commit -m "${msg:-"no commit message"}"
 
+    # Restore flag file
+    if [ -n $INITIALIZED_FILE_FLAG ]; then
+      touch $INITIALIZED_FILE_FLAG
+    fi
+
     if [ $REMOTE_NAME ] && [ $REMOTE_URL ]; then
         # push to repository in the background
         git push $REMOTE_NAME $REMOTE_BRANCH &