# crontab
  [](https://github.com/pre-commit/pre-commit)
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) (>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`.
- Ability to trigger scripts in other containers on completion cron job using `trigger`.
- Ability to share settings between cron jobs using `~~shared-settings` as a key.
## Config file
The config file can be specified 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. Examples: `@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.
- `container`: Full container name. 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. Sub-set includes: `image`, `container`, `command`, `dockerargs`
- `onstart`: Run the command on `crontab` container start, set to `true`. Optional, defaults to false.
See [`config-samples`](config-samples) for examples.
```json
{
"logrotate": {
"schedule":"@every 5m",
"command":"/usr/sbin/logrotate /etc/logrotate.conf"
},
"cert-regen": {
"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":"--it --env-file /opt/crontab/env/letsencrypt.env",
"volumes":["webapp_nginx_tls_cert:/etc/ssl", "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'",
"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/)
1. Add `dockerargs` to your docker-crontab `config.json`
- use `--network NETWORK_NAME` to connect new container into docker-compose network
- use `--name NAME` to use named container
- e.g. `"dockerargs": "--it"`
### Dockerfile
```Dockerfile
FROM registry.gitlab.com/simplicityguy/docker/crontab
COPY config.json ${HOME_DIR}/
```
### Logrotate Dockerfile
```Dockerfile
FROM registry.gitlab.com/simplicityguy/docker/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"]
```