dockcheck/README.md

CLI tool to automate podman image updates or notifying when updates are available.

selective updates, exclude containers, custom labels, notification plugins, prune when done etc.

For Docker - see the original mag37/dockcheck!

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Changelog

• v0.7.1:
  • Added support for multiple notifications using the same template
  • Added support for notification output format
  • Added support for file output
  • Added optional configuration variables per channel to (replace <channel> with any channel name):
    • <channel>_TEMPLATE : Specify a template
    • <channel>_SKIPSNOOZE : Skip snooze
    • <channel>_CONTAINERSONLY : Only notify for podman container related updates
    • <channel>_ALLOWEMPTY : Always send notifications, even when empty
    • <channel>_OUTPUT : Define output format
  • Added advanced configuration system with default.config
  • Added new command line options: -F, -I, -M, -u, -x
  • Added async processing support with xargs
  • Enhanced notification system with notify_v2.sh wrapper
  • Added snooze functionality to prevent duplicate notifications
  • Improved dependency management with automatic downloads
  • Added helper functions: releasenotes(), list_options(), progress_bar()
  • Fixed Quadlet container detection: Restored v0.6.0 behavior of checking ALL containers for updates, including systemd-managed Quadlet containers
• v0.6.0:
  • Grafana & Prometheus Integration:
    • Added a detailed Prometheus metrics exporter that now reports not only the number of containers with updates, no-updates, and errors, but also the total number of containers checked, the duration of the update check, and the epoch timestamp of the last check.
    • Enhanced documentation with instructions on integrating these metrics with Grafana for visual monitoring.
  • Improved Error Handling & Code Refactoring:
    • Introduced set -euo pipefail and local variable scoping within functions to improve reliability and prevent unexpected behaviour.
    • Standardised container name handling and refined the Quadlet detection logic.
  • Self-Update Enhancements:
    • Updated the self-update mechanism to support both Git-based and HTTP-based updates, with an automatic restart that preserves the original arguments.
  • Miscellaneous Improvements:
    • Enhanced dependency installer to support both package manager and static binary installations for jq and regctl.
    • General code refactoring across the project for better readability and maintainability.

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podcheck.sh

$ ./podcheck.sh -h
Syntax:     podcheck.sh [OPTION] [comma separated names to include]
Example:    podcheck.sh -y -x 10 -d 10 -e nextcloud,heimdall

Options:
-a|y   Automatic updates, without interaction.
-c D   Exports metrics as prom file for the prometheus node_exporter. Provide the collector textfile directory.
-d N   Only update to new images that are N+ days old. Lists too recent with +prefix and age. 2xSlower.
-e X   Exclude containers, separated by comma.
-f     Force stop+start stack after update. Caution: restarts once for every updated container within stack.
-F     Only compose up the specific container, not the whole compose stack (useful for master-compose structure).
-h     Print this Help.
-i     Inform - send a preconfigured notification.
-I     Prints custom releasenote urls alongside each container with updates in CLI output (requires urls.list).
-l     Only update if label is set. See readme.
-m     Monochrome mode, no printf colour codes and hides progress bar.
-M     Prints custom releasenote urls as markdown (requires template support).
-n     No updates, only checking availability.
-p     Auto-Prune dangling images after update.
-r     Allow checking for updates/updating images for podman run containers. Won't update the container.
-s     Include stopped containers in the check. (Logic: podman ps -a).
-t N   Set a timeout (in seconds) per container for registry checkups, 10 is default.
-u     Allow automatic self updates - caution as this will pull new code and autorun it.
-v     Prints current version.
-x N   Set max asynchronous subprocesses, 1 default, 0 to disable, 32+ tested.

Basic example:

$ ./podcheck.sh
...
Containers on latest version:
filebrowser
foundryvtt

Containers with updates available:
1) joplin-db
2) it-tools

Choose what containers to update:
Enter number(s) separated by comma, [a] for all - [q] to quit:

Then it proceeds to run podman pull and podman compose up -d, or restarts systemd units for every container with updates. After the updates are complete, you'll be prompted if you'd like to prune dangling images

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Dependencies

• Running podman (duh) and compose, either standalone or plugin.
• Bash shell or compatible shell of at least v4.3
  • POSIX xargs, usually default but can be installed with the findutils package - to enable async.
• jq
  • User will be prompted to install with package manager or download static binary.
• regclient/regctl (Licensed under Apache-2.0 License)
  • User will be prompted to download regctl if not in PATH or PWD.
  • regctl requires amd64/arm64 - see workaround if other architecture is used.

Install Instructions

Download the script to a directory in PATH, I'd suggest using ~/.local/bin as that's usually in PATH.
For OSX/macOS preferably use /usr/local/bin.

# basic example with curl:
curl -L https://raw.githubusercontent.com/sudo-kraken/podcheck/main/podcheck.sh -o ~/.local/bin/podcheck.sh
chmod +x ~/.local/bin/podcheck.sh

# or oneliner with wget:
wget -O ~/.local/bin/podcheck.sh "https://raw.githubusercontent.com/sudo-kraken/podcheck/main/podcheck.sh" && chmod +x ~/.local/bin/podcheck.sh

# OSX or macOS version with curl:
curl -L https://raw.githubusercontent.com/sudo-kraken/podcheck/main/podcheck.sh -o /usr/local/bin/podcheck.sh && chmod +x /usr/local/bin/podcheck.sh

Then call the script anywhere with just podcheck.sh. Add preferred notify.sh-template to the same directory - this will not be touched by the scripts self-update function.

Configuration

For advanced features like notifications and custom settings, you'll need to create a configuration file:

1. Copy the default configuration: cp default.config podcheck.config
2. Place it alongside the script or in ~/.config/
3. Uncomment and modify the settings you want to customize

The podcheck.config file must be present and properly configured for:

• Notification channels (NOTIFY_CHANNELS)
• Custom timeout, async, and update behaviors
• Notification templates and credentials

Without this config file, podcheck will run with default settings and notifications will be disabled.

Alternatively create an alias where specific flags and values are set.
Example alias pc=podcheck.sh -p -x 10 -t 3.

Notifications

Triggered with the -i flag. Will send a list of containers with updates available and a notification when podcheck.sh itself has an update. notify_templates/notify_v2.sh is the default notification wrapper, if notify.sh is present and configured, it will override.

Example of a cron scheduled job running non-interactive at 10'oclock excluding 1 container and sending notifications: 0 10 * * * /home/user123/.local/bin/podcheck.sh -nix 10 -e excluded_container1

Installation and configuration:

Set up a directory structure as below. You only need the notify_templates/notify_v2.sh file and any notification templates you wish to enable, but there is no harm in having all of them present.

 .
├── notify_templates/
│   ├── notify_DSM.sh
│   ├── notify_apprise.sh
│   ├── notify_discord.sh
│   ├── notify_generic.sh
│   ├── notify_gotify.sh
│   ├── notify_matrix.sh
│   ├── notify_ntfy-sh.sh
│   ├── notify_pushbullet.sh
│   ├── notify_pushover.sh
│   ├── notify_smtp.sh
│   ├── notify_telegram.sh
│   └── notify_v2.sh
├── podcheck.config
├── podcheck.sh
└── urls.list         # optional

• Uncomment and set the NOTIFY_CHANNELS="" environment variable in podcheck.config to a space separated string of your desired notification channels to enable.
• Uncomment and set the environment variables related to the enabled notification channels. Eg. GOTIFY_DOMAIN="" + GOTIFY_TOKEN="".

It's recommended to only do configuration with variables within podcheck.config and not modify notify_templates/notify_X.sh directly. If you wish to customize the notify templates yourself, you may copy them to your project root directory alongside the main podcheck.sh (where they're also ignored by git).

Customizing notify_v2.sh is handled the same as customizing the templates, but it must be renamed to notify.sh within the podcheck.sh root directory.

Snooze feature:

Configure to receive scheduled notifications only if they're new since the last notification - within a set time frame.

Example: Podcheck is scheduled to run every hour. You will receive an update notification within an hour of availability.
Snooze enabled: You will not receive a repeated notification about an already notified update within the snooze duration.

Snooze disabled: You will receive additional (possibly repeated) notifications every hour.

To enable snooze uncomment the SNOOZE_SECONDS variable in your podcheck.config and set it to the number of seconds you wish to prevent duplicate alerts.
Snooze is split into three categories; container updates, podcheck.sh self updates and notification template updates.

If an update becomes available for an item that is not snoozed, notifications will be sent and include all available updates for that item's category, even snoozed items.

The actual snooze duration will be 60 seconds less than SNOOZE_SECONDS to account for minor scheduling or run time issues.

Current notify templates:

• Synology DSM
• Email with mSMTP (or deprecated alternative sSMTP)
• Apprise (with it's multitude of notifications)
  • both native caronc/apprise and the standalone linuxserver/docker-apprise-api
  • Read the QuickStart
• ntfy - HTTP-based pub-sub notifications.
• Gotify - a simple server for sending and receiving messages.
• Pushbullet - connecting different devices with cross-platform features.
• Telegram - Telegram chat API.
• Matrix-Synapse - Matrix, open, secure, decentralised communication.
• Pushover - Simple Notifications (to your phone, wearables, desktops)
• Discord - Discord webhooks.

Further additions are welcome - suggestions or PRs! _{^{Initiated and first contributed by mag37.}}

Notification channel configuration:

All required environment variables for each notification channel are provided in the default.config file as comments and must be uncommented and modified for your requirements.
For advanced users, additional functionality is available via custom configurations and environment variables.
Use cases - all configured in podcheck.config:
(replace <channel> with the upper case name of the of the channel as listed in NOTIFY_CHANNELS variable, eg TELEGRAM_SKIPSNOOZE)

• To bypass the snooze feature, even when enabled, add the variable <channel>_SKIPSNOOZE and set it to true.
• To configure the channel to only send container update notifications, add the variable <channel>_CONTAINERSONLY and set it to true.
• To send notifications even when there are no updates available, add the variable <channel>_ALLOWEMPTY and set it to true.
• To use another notification output format, add the variable <channel>_OUTPUT and set it to csv, json, or text. If unset or set to an invalid value, defaults to text.
• To send multiple notifications using the same notification template:
  • Strings in the NOTIFY_CHANNELS list are now treated as unique names and do not necessarily refer to the notification template that will be called, though they do by default.
  • Add another notification channel to NOTIFY_CHANNELS in podcheck.config. The name can contain upper and lower case letters, numbers and underscores, but can't start with a number.
  • Add the variable <channel>_TEMPLATE to podcheck.config where <channel> is the name of the channel added above and set the value to an available notification template script (discord, apprise, gotify, etc.)
  • Add all other environment variables required for the chosen template to function with <channel> in upper case as the prefix rather than the template name.
    • For example, if <channel> is mynotification and the template configured is discord, you would need to set MYNOTIFICATION_WEBHOOK_URL.

Release notes addon

There's a function to use a lookup-file to add release note URL's to the notification message.

Copy the notify_templates/urls.list file to the script directory, it will be used automatically if it's there.
Modify it as necessary, the names of interest in the left column needs to match your container names.
To also list the URL's in the CLI output (choose containers list) use the -I option or variable config.
For Markdown formatting also add the -M option. (this requires the template to be compatible - see gotify for example)

The output of the notification will look something like this:

Containers on hostname with updates available:
apprise-api  -> https://github.com/linuxserver/docker-apprise-api/releases
homer  ->  https://github.com/bastienwirtz/homer/releases
nginx  -> https://github.com/docker-library/official-images/blob/master/library/nginx
...

The urls.list file is just an example and I'd gladly see that people contribute back when they add their preferred URLs to their lists.

Asyncronous update checks with xargs; -x N option. (default=1)

Pass -x N where N is number of subprocesses allowed, experiment in your environment to find a suitable max!

Change the default value by editing the MaxAsync=N variable in podcheck.sh. To disable the subprocess function set MaxAsync=0.

Extra plugins and tools:

Using podcheck.sh with systemd units (Quadlet)

Podcheck automatically detects containers managed by systemd units and will restart them appropriately using systemctl restart.

Prometheus and node_exporter

Podcheck can be used together with Prometheus and node_exporter to export metrics via the file collector, scheduled with cron or likely. This is done with the -c option, like this:

podcheck.sh -c /path/to/exporter/directory

See the README.md for more detailed information on how to set it up!
_{^{Contributed by tdralle.}}

Labels

Optionally add labels to compose-files. Currently these are the usable labels:

    labels:
      sudo-kraken.podcheck.update: true
      sudo-kraken.podcheck.only-specific-container: true
      sudo-kraken.podcheck.restart-stack: true

• sudo-kraken.podcheck.update: true will when used with the -l option only update containers with this label and skip the rest. Will still list updates as usual.
• sudo-kraken.podcheck.only-specific-container: true works instead of the -F option, specifying the updated container when doing compose up, like podman compose up -d homer.
• sudo-kraken.podcheck.restart-stack: true works instead of the -f option, forcing stop+restart on the whole compose-stack (Caution: Will restart on every updated container within stack).

Workaround for non amd64 / arm64

regctl provides binaries for amd64/arm64, to use on other architecture you could try this workaround. Run regctl in a container wrapped in a shell script. Copied from regclient/docs/install.md:

cat >regctl <<EOF
#!/bin/sh
opts=""
case "\$*" in
  "registry login"*) opts="-t";;
esac
podman container run \$opts -i --rm --net host \\
  -u "\$(id -u):\$(id -g)" -e HOME -v \$HOME:\$HOME \\
  -v /etc/docker/certs.d:/etc/docker/certs.d:ro \\
  ghcr.io/regclient/regctl:latest "\$@"
EOF
chmod 755 regctl

Test it with ./regctl --help and then either add the file to the same path as podcheck.sh or in your path (eg. ~/.local/bin/regctl).

Function to auth with docker hub before running

Example - Change names, paths, and remove cat+password flag if you rather get prompted:

function pchk {
  cat ~/pwd.txt | podman login --username YourUser --password-stdin docker.io
  ~/podcheck.sh "$@"
}

-r flag disclaimer and warning

Wont auto-update the containers, only their images. (compose is recommended)
podman run dont support using new images just by restarting a container.
Containers need to be manually stopped, removed and created again to run on the new image.
Using the -r option together with eg. -i and -n to just check for updates and send notifications and not update is safe though!

Known issues

• No detailed error feedback (just skip + list what's skipped).
• Not respecting --profile options when re-creating the container.
• Not working well with containers created by Portainer.

Debugging

If you hit issues, you could check the output of the extras/errorCheck.sh script for clues. Another option is to run the main script with debugging in a subshell bash -x podcheck.sh - if there's a particular container/image that's causing issues you can filter for just that through bash -x podcheck.sh nginx.

License

podcheck is created and released under the GNU GPL v3.0 license.

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The Story Behind Podcheck

Podcheck was created to bring the convenience of automated container updates to the Podman ecosystem. As a user of Dockcheck for Docker, the need for a similar tool for Podman became apparent. Podcheck aims to provide the same ease of use and automation, tailored for Podman users.

Acknowledgments

Podcheck is inspired by the original Dockcheck script. Without Dockcheck, there wouldn't have been a Podcheck. Many thanks to mag37 and all the contributors to Dockcheck for their work and inspiration.