init commit

.gitignore

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+.idea
+*.iml
+
+config.json

Dockerfile

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+FROM library/alpine:3.5
+
+ENV HOME_DIR=/opt/crontab
+RUN apk add --no-cache --virtual .run-deps bash curl jq docker \
+    && mkdir -p ${HOME_DIR}
+
+# Dev
+COPY config.json ${HOME_DIR}/
+
+COPY docker-entrypoint /
+ENTRYPOINT ["/docker-entrypoint"]
+
+HEALTHCHECK --interval=5s --timeout=3s \
+    CMD ps aux | grep '[c]rond' || exit 1
+
+CMD ["crond","-f"]

README.md

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+# docker-crontab
+
+A simple wrapper over `docker` to all complex cron job to be run in other containers.
+
+## Why?
+Yes, I'm aware of [mcuadros/ofelia](https://github.com/mcuadros/ofelia), it was the main inspiration for this project. 
+A great project, don't get me wrong. It was just missing certain key enterprise features.
+
+## Features
+- Easy to read schedule syntax allowed.
+- Allows for comments, cause we all need friendly reminders of what `update_script.sh` actually does.
+- Start an image using `image`.
+- Run command in a container using `container`.
+- Run command on a instances of a scaled container using `project`.
+- Ability to trigger scripts in other containers on completion cron job using `trigger`.
+
+## Config.json
+- `comment`: Comments to be included with crontab entry
+- `schedule`: Crontab schedule syntax as described in https://godoc.org/github.com/robfig/cron. Ex `@hourly`, `@every 1h30m`, `* * * * * *`. Required.
+- `command`: Command to be run on docker container/image. Required.
+- `image`: Docker images name (ex `library/alpine:3.5`). Optional.
+- `project`: Docker Compose/Swarm project name. Optional, only applies when `contain` is included.
+- `container`: Full container name or container alias if `project` is set. Ignored if `image` is included.
+- `dockerargs`: Command line docker `run`/`exec` arguments for full control. Defaults to ` `.
+- `trigger`: Array of docker-crontab subset objects. Subset includes: `image`,`project`,`container`,`command`,`dockerargs` 
+
+See `./config.sample.json` for examples.
+
+## Examples
+
+### Command Line
+```bash
+docer build -t crontab .
+docker run -d \
+    -v /var/run/docker.sock:/var/run/docker.sock \
+    crontab
+```
+
+### Dockerfile
+```Dockerfile
+FROM willfarrell/crontab
+
+COPY config.json ${HOME_DIR}/
+```
+
+### Logrotate Dockerfile
+```Dockerfile
+FROM willfarrell/crontab
+
+RUN apk add --no-cache logrotate
+RUN echo "*/5 *	* * *  /usr/sbin/logrotate /etc/logrotate.conf" >> /etc/crontabs/logrotate
+ADD logrotate.conf /etc/logrotate.conf
+
+CMD ["crond", "-f"]
+```
+
+## TODO
+- [ ] Make smaller by using busybox?
+- [ ] Have ability to auto regenerate crontab on file change
+- [ ] Run commands on host machine
+- [ ] Write tests
+- [ ] Setup TravisCI

config.sample.json

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+[{
+	"comment":"cron with triggered commands",
+	"schedule":"* * * * *",
+	"command":"echo hello",
+	"project":"crontab",
+	"container":"myapp",
+	"trigger":[{
+		"command":"echo world",
+		"container":"crontab_myapp_1"
+	}]
+},{
+	"comment":"map a volume",
+	"schedule":"* * * * *",
+	"dockerargs":"-d -v /tmp:/tmp",
+	"command":"echo new",
+	"image":"alpine:3.5"
+},{
+	"comment":"use an ENV from inside a container",
+	"schedule":"@hourly",
+	"dockerargs":"-d -e FOO=BAR",
+	"command":"sh -c 'echo hourly ${FOO}'",
+	"image":"alpine:3.5"
+},{
+	"comment":"trigger every 2 min",
+	"schedule":"@every 2m",
+	"command":"echo 2 minute",
+	"image":"alpine:3.5",
+	"trigger":[{
+		"command":"echo world",
+		"container":"crontab_myapp_1"
+	}]
+}]

docker-compose.yml

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+version: "2.1"
+
+services:
+  myapp:
+    image: alpine:3.5
+    restart: always
+    command: "sh -c 'while :; do sleep 1; done'"
+
+  crontab:
+    build: .
+    restart: always
+    volumes:
+     - "/var/run/docker.sock:/var/run/docker.sock"

docker-entrypoint

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+#!/usr/bin/env bash
+set -e
+
+# for local testing only
+#HOME_DIR=.
+
+CONFIG=${HOME_DIR}/config.json
+DOCKER_SOCK=/var/run/docker.sock
+CRONTAB_FILE=${HOME_DIR}/docker
+
+make_image_cmd() {
+    DOCKERARGS=$(echo ${TMP_JSON} | jq -r .dockerargs)
+    if [ "${DOCKERARGS}" == "null" ]; then DOCKERARGS=; fi
+    IMAGE=$(echo ${TMP_JSON} | jq -r .image)
+    TMP_COMMAND=$(echo ${TMP_JSON} | jq -r .command)
+    echo "docker run ${DOCKERARGS} ${IMAGE} ${TMP_COMMAND}"
+}
+
+make_container_cmd() {
+    DOCKERARGS=$(echo ${TMP_JSON} | jq -r .dockerargs)
+    if [ "${DOCKERARGS}" == "null" ]; then DOCKERARGS=; fi
+    PROJECT=$(echo ${TMP_JSON} | jq -r .project)
+    CONTAINER=$(echo ${TMP_JSON} | jq -r .container)
+    TMP_COMMAND=$(echo ${TMP_JSON} | jq -r .command)
+
+    COMMAND_ARR=()
+
+    if [ "${PROJECT}" != "null" ]; then
+
+        # create bash script to detect all running containers
+        SCRIPT_NAME=$(cat /proc/sys/kernel/random/uuid)
+cat << EOF > ${HOME_DIR}/${SCRIPT_NAME}
+!#/bin/bash
+set -e
+
+CONTAINERS=\$(curl --no-buffer -s -XGET --unix-socket ${DOCKER_SOCK} http://localhost/containers/json | jq -r .[].Names[0] | sed 's@/@@')"
+for CONTAINER_NAME in \$CONTAINERS; do
+    if [[ "\${CONTAINER_NAME}" =~ ^${PROJECT}_${CONTAINER}.+ ]]; then
+        docker exec ${DOCKERARGS} \${CONTAINER_NAME} ${TMP_COMMAND}
+    fi
+done
+EOF
+        echo "sh ${HOME_DIR}/${SCRIPT_NAME}"
+    else
+        echo "docker exec ${DOCKERARGS} ${CONTAINER} ${TMP_COMMAND}"
+    fi
+}
+
+make_cmd() {
+    IMAGE=$(echo ${TMP_JSON} | jq -r .image)
+    CONTAINER=$(echo ${TMP_JSON} | jq -r .container)
+    if [ "${IMAGE}" != "null" ]; then
+        make_image_cmd
+    elif [ "${CONTAINER}" != "null" ]; then
+        make_container_cmd
+    else
+        echo "echo 'Error making docker command, image or container param missing.'"
+    fi
+}
+
+parse_schedule() {
+	case $1 in
+        "@yearly")
+            echo "0 0 0 1 1 *"
+            ;;
+        "@annually")
+            echo "0 0 0 1 1 *"
+            ;;
+        "@monthly")
+            echo "0 0 0 1 * *"
+            ;;
+        "@weekly")
+            echo "0 0 0 * * 0"
+            ;;
+        "@daily")
+            echo "0 0 0 * * *"
+            ;;
+        "@midnight")
+            echo "0 0 0 * * *"
+            ;;
+        "@hourly")
+            echo "0 0 * * * *"
+            ;;
+        "@every")
+            TIME=$2
+            TOTAL=0
+
+            M=$(echo $TIME | grep -o '[0-9]\+m')
+            H=$(echo $TIME | grep -o '[0-9]\+h')
+            D=$(echo $TIME | grep -o '[0-9]\+d')
+
+            if [ -n "${M}" ]; then
+                TOTAL=$(($TOTAL + ${M::-1}))
+            fi
+            if [ -n "${H}" ]; then
+                TOTAL=$(($TOTAL + ${H::-1} * 60))
+            fi
+            if [ -n "${D}" ]; then
+                TOTAL=$(($TOTAL + ${D::-1} * 60 * 24))
+            fi
+
+            echo "*/${TOTAL} * * * * *"
+            ;;
+        *)
+            echo "${@}"
+            ;;
+    esac
+}
+
+function build_crontab() {
+    rm -rf ${CRONTAB_FILE}
+    while read i ; do
+        #echo "parse $(jq .[$i] ${CONFIG})"
+
+        SCHEDULE=$(jq -r .[$i].schedule ${CONFIG} | sed 's/\*/\\*/g')
+        if [ "${SCHEDULE}" == "null" ]; then
+            echo "Schedule Missing: $(jq -r .[$i].schedule ${CONFIG})"
+            continue
+        fi
+        SCHEDULE=$(parse_schedule ${SCHEDULE} | sed 's/\\//g')
+
+        if [ "$(jq -r .[$i].command ${CONFIG})" == "null" ]; then
+            echo "Command Missing: $(jq -r .[$i].command ${CONFIG})"
+            continue
+        fi
+
+        TMP_JSON=$(jq -c .[$i] ${CONFIG})
+        COMMAND=$(make_cmd)
+        if [ "$(jq -r .[$i].trigger ${CONFIG})" != "null" ]; then
+            while read j ; do
+                echo "trigger parse $(jq .[$i].trigger[$j] ${CONFIG})"
+                if [ "$(jq .[$i].trigger[$j].command ${CONFIG})" == "null" ]; then
+                    echo "Command Missing: $(jq -r .[$i].trigger[$j].command ${CONFIG})"
+                    continue
+                fi
+                TMP_JSON=$(jq -c .[$i].trigger[$j] ${CONFIG})
+                COMMAND="$COMMAND && $(make_cmd)"
+            done < <(jq -r '.['$i'].trigger|keys[]' ${CONFIG})
+        fi
+
+        NAME=$(jq -r .[$i].name ${CONFIG})
+        COMMENT=$(jq -r .[$i].comment ${CONFIG})
+        if [ "${NAME}" != "null" ] && [ "${COMMENT}" != "null" ]; then
+            echo "# ${NAME}: ${COMMENT}" >> ${CRONTAB_FILE}
+        elif [ "${COMMENT}" != "null" ]; then
+            echo "# ${COMMENT}" >> ${CRONTAB_FILE}
+        fi
+
+        echo "${SCHEDULE} ${COMMAND}" >> ${CRONTAB_FILE}
+    done < <(jq -r '.|keys[]' ${CONFIG})
+
+    echo "crontab generation complete"
+    cat ${CRONTAB_FILE}
+}
+
+# Used to pass json to functions - total hack, I know
+TMP_JSON=
+
+if [ "$1" = "crond" ] && [ -f ${CONFIG} ]; then
+    build_crontab
+fi
+
+echo "$@"
+exec "$@"