Ability to execute any command passed to container

Author: ryzy

Dockerfile

@@ -13,4 +13,4 @@ RUN \
 # Add supervisord conf, bootstrap.sh files
 ADD container-files /
 
-CMD ["/config/bootstrap.sh"]
+ENTRYPOINT ["/config/bootstrap.sh"]

README.md

@@ -1,25 +1,35 @@
-# CentOS-7 with supervisord launcher
+# CentOS-7 with supervisord launcher | Docker
 
 This is a CentOS-7 Docker [million12/centos-supervisor](https://registry.hub.docker.com/u/million12/centos-supervisor/) image, perfect in case when you need to launch more then one process inside a container. This image is based on official [centos:centos7](https://registry.hub.docker.com/_/centos/) and it adds only ca. 20MB on top of it.
 
-Things included:
+## What's included
 
-##### - init scripts
+##### - bootstrap.sh script
+
+The container has an **ENTRYPOINT** set to `/config/bootstrap.sh`. It iterates through all `/config/init/*.sh` scripts and runs them, then launches supervisord. See [bootstrap.sh](container-files/config/bootstrap.sh) for details.
 
-Add your .sh scripts to `/config/init` to have them executed when container starts. The bootstrap script is configured to run them just before supervisord starts. See [million12/nginx](https://github.com/million12/docker-nginx) for examples.
+By default, the **CMD** option in Dockerfile is empty, but the bootstrap.sh script is configured to run everything which is passed into it. Therefore you can launch it in several ways:
+* detached mode, no argument(s) passed: supervisord starts in foreground mode and stays until container is stopped.
+* detached mode, some argument(s) passed: arguments are executed; supervisord starts in foreground mode and stays until container is stopped.
+* interactive mode with TTY (-it), no argument(s) passed: supervisord starts in background mode; interactive bash waits for user input. Exiting from bash (CMD+D) exists the container.
+* interactive mode with TTY (-it), some argument(s) passed: supervisord starts in background mode, passed command is executed; container exits.
 
 ##### - supervisord
 
-Just add you supervisord config(s) to `/etc/supervisor.d/` directory to launch your service. For example in your `Dockerfile` you could put:  
+Supervisord is installed and loads services to run from `/etc/supervisor.d/` directory. Add your own files there to launch your services. For example in your `Dockerfile` you could put:  
 ```ADD my-supervisord-service.conf /etc/supervisord.d/my-supervisord-service.conf```
 
 Learn more about about [supervisord inside containers on official Docker documentation](https://docs.docker.com/articles/using_supervisord/).
 
+##### - init scripts
+
+You can add your .sh scripts to `/config/init` directory to have them executed when container starts. The bootstrap script is configured to run them just before supervisord starts. See [million12/nginx](https://github.com/million12/docker-nginx) for example usage.
+
 ##### - error logging
 
 Logfile for supervisord is switched off to avoid logging inside container. Instead, all logs are easily available via `docker logs [container name]`.
 
-This is probably the best approach if you'd like to source your logs from outside the container via `docker logs` (also via CoreOS `journald') and you don't want to worry about logging and log management inside your container and/or data volume.
+This is probably the best approach if you would like to source your logs from outside the container via `docker logs` (also via CoreOS `journald') and you do not want to worry about logging and log management inside your container and/or data volume.
 
 ##### - /data volume
 
@@ -36,20 +46,27 @@ Recommended structure:
 
 ## Usage
 
-This container is configured to run your service(s) both in interactive and non-interactive mode (see [bootstrap.sh](config/init/bootstrap.sh) script).
+As explained above, this container is configured to run your service(s) both in interactive and non-interactive modes.
 
-`docker run -it million12/centos-supervisor` (interactive)  
-`docker run -d million12/centos-supervisor` (detached, non-interactive)
+`docker run -it million12/centos-supervisor`: runs supervisord, then interactive bash shell and waits for user's input. Exiting from the shell kills the container.
+
+`docker run -it million12/centos-supervisor ps aux`:  runs supervisord, then `ps aux` command inside container and exists.
+
+`docker run -it million12/centos-supervisor top`:  runs supervisord, then `top` tool. Exiting from top exits the container.
+
+`docker run -d million12/centos-supervisor`: detached, runs supervisord in foreground mode and its configured services
+
+`docker run -d million12/centos-supervisor touch 'test-file'`: detached, runs `touch 'test-file'` command, then supervisord in foreground mode and its configured services
 
 
 ## Build
 
-`docker build --tag=million12/centos-supervisor`
+`docker build --tag=million12/centos-supervisor .`
 
 
 ## Author
 
 Author: Marcin Ryzycki (<marcin@m12.io>)  
 Author: Przemyslaw Ozgo (<linux@ozgo.info>)
 
-This work is also inspired by [maxexcloo](https://github.com/maxexcloo)'s work on his [docker images](https://github.com/maxexcloo/Docker). Thanks!
+This work is also inspired by [maxexcloo](https://github.com/maxexcloo)'s work on his [docker images](https://github.com/maxexcloo/Docker). Many thanks!

container-files/config/bootstrap.sh

@@ -1,6 +1,11 @@
 #!/bin/bash
 
 set -e
+set -u
+
+# Supervisord default params
+SUPERVISOR_PARAMS='-c /etc/supervisord.conf'
+
 
 # Create directories for supervisor's UNIX socket and logs (which might be missing
 # as container might start with /data mounted from another data-container).
@@ -13,19 +18,30 @@ if [ "$(ls /config/init/)" ]; then
 fi
 
 
-SUPERVISOR_PARAMS='-c /etc/supervisord.conf'
-
-# Do we have TTY?
+# We have TTY, so probably an interactive container...
 if test -t 0; then
+  # Run supervisord detached...
   supervisord $SUPERVISOR_PARAMS
-  while true; do
-    # echo "Exit supervisorctl with Ctrl-D. Detach with Ctrl-P + Ctrl-Q."
-    # supervisorctl $SUPERVISOR_PARAMS
-    echo "Exit shell with Ctrl-D. Detach with Ctrl-P + Ctrl-Q."
+  
+  # Some command(s) has been passed to container? Execute them and exit.
+  # No commands provided? Run bash.
+  if [[ $@ ]]; then 
+    eval $@
+  else 
     export PS1='[\u@\h : \w]\$ '
-    bash
-  done
-fi
+    /bin/bash
+  fi
 
-# Run supervisord in foreground when no TTY
-supervisord -n $SUPERVISOR_PARAMS
+# Detached mode? Run supervisord in foreground, which will stay until container is stopped.
+else
+  # If some extra params were passed, execute them before.
+  # @TODO It is a bit confusing that the passed command runs *before* supervisord, 
+  #       while in interactive mode they run *after* supervisor.
+  #       Not sure about that, but maybe when any command is passed to container,
+  #       it should be executed *always* after supervisord? And when the command ends,
+  #       container exits as well.
+  if [[ $@ ]]; then 
+    eval $@
+  fi
+  supervisord -n $SUPERVISOR_PARAMS
+fi