Merge pull request #27 from sergey-shambir/docs-for-docker-compose-use-case

Documented usage with docker-compose

Dockerfile

@@ -1,7 +1,7 @@
 FROM library/docker:stable
 
 ENV HOME_DIR=/opt/crontab
-RUN apk add --no-cache --virtual .run-deps bash jq \
+RUN apk add --no-cache --virtual .run-deps gettext bash jq \
     && mkdir -p ${HOME_DIR}/jobs ${HOME_DIR}/projects \
     && adduser -S docker -D
 
@@ -11,4 +11,4 @@ ENTRYPOINT ["/docker-entrypoint"]
 HEALTHCHECK --interval=5s --timeout=3s \
     CMD ps aux | grep '[c]rond' || exit 1
 
-CMD ["crond","-f"]
+CMD ["crond", "-f", "-d", "6", "-c", "/etc/crontabs"]

README.md

@@ -57,6 +57,7 @@ See [`config.sample.json`](https://github.com/willfarrell/docker-crontab/blob/ma
 ## How to use
 
 ### Command Line
+
 ```bash
 docker build -t crontab .
 docker run -d \
@@ -67,7 +68,19 @@ docker run -d \
     crontab
 ```
 
+### Use with docker-compose
+
+1. Figure out which network name used for your docker-compose containers
+	* use `docker network ls` to see existing networks
+	* if your `docker-compose.yml` is in `my_dir` directory, you probably has network `my_dir_default`
+	* otherwise [read the docker-compose docs](https://docs.docker.com/compose/networking/)
+2. Add `dockerargs` to your docker-crontab `config.json`
+	* use `--network NETWORK_NAME` to connect new container into docker-compose network
+	* use `--rm --name NAME` to use named container
+	* e.g. `"dockerargs": "--network my_dir_default --rm --name my-best-cron-job"`
+
 ### Dockerfile
+
 ```Dockerfile
 FROM willfarrell/crontab
 
@@ -76,6 +89,7 @@ COPY config.json ${HOME_DIR}/
 ```
 
 ### Logrotate Dockerfile
+
 ```Dockerfile
 FROM willfarrell/crontab
 
@@ -87,13 +101,13 @@ CMD ["crond", "-f"]
 ```
 
 ### Logging - In Dev
+
 All `stdout` is captured, formatted, and saved to `/var/log/crontab/jobs.log`. Set `LOG_FILE` to `/dev/null` to disable logging.
 
 example: `e6ced859-1563-493b-b1b1-5a190b29e938 2017-06-18T01:27:10+0000 [info] Start Cronjob **map-a-vol** map a volume`
 
 grok: `CRONTABLOG %{DATA:request_id} %{TIMESTAMP_ISO8601:timestamp} \[%{LOGLEVEL:severity}\] %{GREEDYDATA:message}`
 
-
 ## TODO
 - [ ] Have ability to auto regenerate crontab on file change (signal HUP?)
 - [ ] Run commands on host machine (w/ --privileged?)

docker-entrypoint

@@ -22,12 +22,26 @@ CRONTAB_FILE=/etc/crontabs/docker
 # Ensure dir exist - in case of volume mapping
 mkdir -p ${HOME_DIR}/jobs ${HOME_DIR}/projects
 
-# Create docker group using correct gid from host, and add docker user to it
-if ! grep -q "^docker:" /etc/group; then
+ensure_docker_socket_accessible() {
+    if ! grep -q "^docker:" /etc/group; then
+        # Ensure 'docker' user has permissions for docker socket (without changing permissions)
         DOCKER_GID=$(stat -c '%g' ${DOCKER_SOCK})
+        if [ "${DOCKER_GID}" != "0" ]; then
+            if ! grep -qE "^[^:]+:[^:]+:${DOCKER_GID}:" /etc/group; then
+                # No group with such gid exists - create group docker
                 addgroup -g ${DOCKER_GID} docker
                 adduser docker docker
-fi
+            else
+                # Group with such gid exists - add user "docker" to this group
+                DOCKER_GROUP_NAME=`getent group "${DOCKER_GID}" | awk -F':' '{{ print $1 }}'`
+                adduser docker $DOCKER_GROUP_NAME
+            fi
+        else
+            # Docker socket belongs to "root" group - add user "docker" to this group
+            adduser docker root
+        fi
+    fi
+}
 
 slugify() {
     echo "$@" | iconv -t ascii | sed -r s/[~\^]+//g | sed -r s/[^a-zA-Z0-9]+/-/g | sed -r s/^-+\|-+$//g | tr A-Z a-z
@@ -36,7 +50,7 @@ slugify() {
 make_image_cmd() {
     DOCKERARGS=$(echo ${1} | jq -r .dockerargs)
     if [ "${DOCKERARGS}" == "null" ]; then DOCKERARGS=; fi
-    IMAGE=$(echo ${1} | jq -r .image)
+    IMAGE=$(echo ${1} | jq -r .image | envsubst)
     TMP_COMMAND=$(echo ${1} | jq -r .command)
     echo "docker run ${DOCKERARGS} ${IMAGE} ${TMP_COMMAND}"
 }
@@ -45,8 +59,9 @@ make_container_cmd() {
     DOCKERARGS=$(echo ${1} | jq -r .dockerargs)
     if [ "${DOCKERARGS}" == "null" ]; then DOCKERARGS=; fi
     SCRIPT_NAME=$(echo ${1} | jq -r .name)
+    SCRIPT_NAME=$(slugify $SCRIPT_NAME)
     PROJECT=$(echo ${1} | jq -r .project)
-    CONTAINER=$(echo ${1} | jq -r .container)
+    CONTAINER=$(echo ${1} | jq -r .container | envsubst)
     TMP_COMMAND=$(echo ${1} | jq -r .command)
 
     if [ "${PROJECT}" != "null" ]; then
@@ -215,6 +230,8 @@ EOF
     done
 }
 
+ensure_docker_socket_accessible
+
 if [ "$1" = "crond" ]; then
     if [ -f ${CONFIG} ]; then
         build_crontab