6416dd8731
If the Nextcloud container is recreated while the cronjob container is still running, the ID of the container is obtained each time the cron tasks are executed. Previously it was cached on entrypoint, so if the ID changed this container would fail.
140 lines
5.6 KiB
Markdown
140 lines
5.6 KiB
Markdown
# Nextcloud Cron Job Docker Container
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## Summary
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This container is designed to run along side your Nextcloud container to execute its
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`/var/www/html/cron.php` at a regular interval. There is an "official" way of doing this, however it
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doesn't work when you run your Nextcloud container using a non-root user. I also personally feel
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that this solution is easier to manage, since it doesn't require the same environment as Nextcloud
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itself (i.e. no network requirements, no database requirements, etc).
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## Setup Instructions
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Since Nextcloud's entire setup can get rather complex with Docker, I highly recommend you set up
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everything using [Docker Compose](https://docs.docker.com/compose/).
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Below is an example of how you set up your `docker-compose.yml` to work with Nextcloud using this
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container. Note that the `app` service is greatly simplified for example purposes. It is only to
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show usage of the cronjob image in conjunction with your Nextcloud container.
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```yml
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version: '3.7'
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services:
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app:
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image: nextcloud:apache
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cron:
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image: rcdailey/nextcloud-cronjob
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restart: always
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network_mode: none
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depends_on:
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- app
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volumes:
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- /var/run/docker.sock:/var/run/docker.sock:ro
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- /etc/localtime:/etc/localtime:ro
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environment:
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- NEXTCLOUD_CONTAINER_NAME=app
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- NEXTCLOUD_PROJECT_NAME=nextcloud
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```
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In this example, the `cron` service runs with a dependency on `app` (which is Nextcloud itself).
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Every 15 minutes (default) the `cron` service will execute `php -f /var/www/html/cron.php` via the
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`docker exec` command. The `NEXTCLOUD_CONTAINER_NAME` and `NEXTCLOUD_PROJECT_NAME` work together to
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help identify the right container to execute the command in.
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Note that if you don't use Docker Compose, you can leave `NEXTCLOUD_PROJECT_NAME` blank or omitted
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entirely.
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## Environment Variables
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* `NEXTCLOUD_CONTAINER_NAME`<br>
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Required. This is the name of the running Nextcloud container (or
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the service, if `NEXTCLOUD_PROJECT_NAME` is specified).
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* `NEXTCLOUD_PROJECT_NAME`<br>
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The name of the project if you're using Docker Compose. The name of the project, by default, is
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the name of the context directory you ran your `docker-compose.yml` from. This helps to build a
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"hint" used to identify the Nextcloud container by name. The hint is built as:
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```txt
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${NEXTCLOUD_PROJECT_NAME}_${NEXTCLOUD_CONTAINER_NAME}
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```
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* `NEXTCLOUD_CRON_MINUTE_INTERVAL`<br>
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The interval, in minutes, of how often the cron task executes. The default is 15 minutes.
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* `NEXTCLOUD_EXEC_USER`<br>
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The user that should be used to run the cron tasks inside the Nextcloud container. This parameter
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is specified to the `docker exec` command from this container. By default, the user used is
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`www-data`, which is also the default user used inside Nextcloud, unless you've overridden it. You
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may also define this environment variable to be blank (e.g. `NEXTCLOUD_EXEC_USER=`) which results
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in the tasks being executed using the Nextcloud container's running user. Specifically, the
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`--user` option will *not* be provided to the `docker exec` command.
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## Container Health
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If you do `docker-compose ps`, you will see the active health of the container. The following logic
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is checked every interval of the health check. If any of these checks fail, it is likely the
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container's health status will become *unhealthy*. In this case, you should restart the container.
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1. The `crond` process must be running.
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2. The Nextcloud container must be available and running.
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Because the Nextcloud container can be restarted while the the cronjob container is running, its
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container ID is not cached. Each time the cron task executes, it searches for the ID of the
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container. This ensures that even if you restart the Nextcloud container, the cronjob container will
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always function.
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## Customizing Cron Tasks
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This container provides the ability for you to run additional tasks inside the Nextcloud container
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in addition to the default `cron.php` task. To add your custom tasks, follow these steps:
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1. Write a shell script that runs the commands that will be part of your task. This shell script
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must have the `.sh` extension. An example of the contents of such a script is below. As an
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optional security measure, do not make this shell script executable. The contents of the file are
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piped into `bash`, so the executable bit is not used.
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```sh
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#!/usr/bin/env bash
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php -f /var/www/html/cron.php
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```
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2. Mount this shell script inside the `/cron-scripts` directory. Here's an example if you're using
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`docker-compose.yml`:
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```yml
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services:
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cron:
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image: rcdailey/nextcloud-cronjob
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volumes:
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- ./my-scripts/do-something.sh:/cron-scripts/do-something.sh:ro
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```
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3. Recreate the container. Your script will now execute in the Nextcloud container at a regular
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interval.
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### Notes
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* All cron task shell scripts run at the same interval defined by `NEXTCLOUD_CRON_MINUTE_INTERVAL`.
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* Modification of your own shell scripts on the host do not require that you restart/recreate the
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container.
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## Debugging
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All logs from `crond` are configured to print to stdout, so you can monitor container logs (via
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`docker-compose logs -f`). This should allow you to make sure your cron job is working. You can also
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use the "Overview" page in Nextcloud Settings to see if the cron job is being run regularly. Here is
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an example of the logs you will see:
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```txt
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Started crond
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-------------------------------------------------------------
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Executing Cron Tasks: Thu Dec 6 17:28:00 CST 2018
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-------------------------------------------------------------
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> Running Script: occ-preview-pre-generate.sh
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> Running Script: run_cron_php.sh
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> Done
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```
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