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docker-crontab

(★ 317)

A docker job scheduler (aka. crontab for docker)

File Explorer

Download Latest Version (.zip)

- - build.yml
- FUNDING.yml
- config.sample.json
- config.sample.mapping.json
- config.sample.mapping.yml
- config.sample.toml
- config.sample.yml
.gitignore
docker-compose.yml
docker-entrypoint
Dockerfile
LICENSE
README.md
test_logging

# Installation Guide

1. Get the code

git clone https://github.com/willfarrell/docker-crontab

Downloads the entire project code from GitHub to your computer.

cd docker-crontab

Moves into the project folder you just downloaded.

2. Docker

Easy Recommended

Prerequisites

Git Needed to download the project code from GitHub.
Docker Desktop Needed to build and run containers. Install it and keep it running in the background.

docker build -t crontab .

Builds a runnable image based on the Dockerfile.

docker run -d \

Runs the built image as an actual container.

-v /var/run/docker.sock:/var/run/docker.sock:ro \

Type this command into your terminal and run it.

* use `docker network ls` to see existing networks

Type this command into your terminal and run it.

* if your `docker-compose.yml` is in `my_dir` directory, you probably has network `my_dir_default`

Runs the command against the services defined in the compose file.

✅ Run docker compose ps to check the containers are Up. If the README mentions a port, open http://localhost:PORT in your browser.

Pulled directly from this repo's README.

// repository documentation

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# docker-crontab

A simple wrapper over `docker` to all complex cron job to be run in other containers.

## Supported tags and Dockerfile links

-	[`latest` (*Dockerfile*)](https://github.com/willfarrell/docker-crontab/blob/master/Dockerfile)
-	[`1.0.0` (*Dockerfile*)](https://github.com/willfarrell/docker-crontab/blob/1.0.0/Dockerfile)
-	[`0.6.0` (*Dockerfile*)](https://github.com/willfarrell/docker-crontab/blob/0.6.0/Dockerfile)

![](https://img.shields.io/docker/pulls/willfarrell/crontab "Total docker pulls") [![](https://images.microbadger.com/badges/image/willfarrell/crontab.svg)](http://microbadger.com/images/willfarrell/crontab "Get your own image badge on microbadger.com")

## Why?
Yes, I'm aware of [mcuadros/ofelia](https://github.com/mcuadros/ofelia) (>250MB when this was created), it was the main inspiration for this project. 
A great project, don't get me wrong. It was just missing certain key enterprise features I felt were required to support where docker is heading.

## 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 file

The config file can be specifed in any of `json`, `toml`, or `yaml`, and can be defined as either an array or mapping (top-level keys will be ignored; can be useful for organizing commands)

- `name`: Human readable name that will be used as the job filename. Will be converted into a slug. Optional.
- `comment`: Comments to be included with crontab entry. Optional.
- `schedule`: Crontab schedule syntax as described in https://en.wikipedia.org/wiki/Cron. Ex `@hourly`, `@every 1h30m`, `* * * * *`. Required.
- `command`: Command to be run on in crontab container or 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. Optional.
- `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` 
- `onstart`: Run the command on `crontab` container start, set to `true`. Optional, defaults to falsey.

See [`config-samples`](config-samples) for examples.

```json
[{
 	"schedule":"@every 5m",
 	"command":"/usr/sbin/logrotate /etc/logrotate.conf"
 },{
 	"comment":"Regenerate Certificate then reload nginx",
 	"schedule":"43 6,18 * * *",
 	"command":"sh -c 'dehydrated --cron --out /etc/ssl --domain ${LE_DOMAIN} --challenge dns-01 --hook dehydrated-dns'",
 	"dockerargs":"--env-file /opt/crontab/env/letsencrypt.env -v webapp_nginx_tls_cert:/etc/ssl -v webapp_nginx_acme_challenge:/var/www/.well-known/acme-challenge",
 	"image":"willfarrell/letsencrypt",
 	"trigger":[{
 		"command":"sh -c '/etc/scripts/make_hpkp ${NGINX_DOMAIN} && /usr/sbin/nginx -t && /usr/sbin/nginx -s reload'",
 		"project":"conduit",
 		"container":"nginx"
 	}],
 	"onstart":true
 }]
```

## How to use

### Command Line

```bash
docker build -t crontab .
docker run -d \
    -v /var/run/docker.sock:/var/run/docker.sock:ro \
    -v ./env:/opt/env:ro \
    -v /path/to/config/dir:/opt/crontab:rw \
    -v /path/to/logs:/var/log/crontab:rw \
    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

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
COPY logrotate.conf /etc/logrotate.conf

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?)
- [ ] Write tests
- [ ] Setup TravisCI