Notifications¶

Updock can send webhook notifications when containers are updated, allowing integration with Slack, Discord, Microsoft Teams, and custom services.

Webhook Configuration¶

Set one or more webhook URLs using the --webhook-url flag or environment variable:

docker run -d \
  -e UPDOCK_WEBHOOK_URL="https://hooks.slack.com/services/T00/B00/xxx" \
  -v /var/run/docker.sock:/var/run/docker.sock \
  updock/updock

Multiple Webhook URLs¶

Provide multiple URLs as a comma-separated list to notify several services simultaneously:

UPDOCK_WEBHOOK_URL="https://hooks.slack.com/services/xxx,https://discord.com/api/webhooks/yyy"

Info

Each URL receives the same payload. Updock sends notifications to all configured endpoints in parallel.

Notification Payload¶

Updock sends a JSON POST request with the following structure:

{
  "text": "Updated container 'nginx' (nginx:1.24 → nginx:1.25)",
  "containers": [
    {
      "name": "nginx",
      "old_image": "nginx:1.24",
      "new_image": "nginx:1.25",
      "updated_at": "2025-01-15T10:30:00Z"
    }
  ]
}

The text field is compatible with Slack and Discord incoming webhooks out of the box.

Custom Templates¶

Override the default message format with --notification-template:

UPDOCK_NOTIFICATION_TEMPLATE="Container {{.Name}} updated from {{.OldImage}} to {{.NewImage}}"

Available template variables:

Variable	Description
`{{.Name}}`	Container name
`{{.OldImage}}`	Previous image reference
`{{.NewImage}}`	New image reference
`{{.UpdatedAt}}`	Timestamp of the update
`{{.Hostname}}`	Host where Updock is running

Tip

Templates use Go's text/template syntax. You can use conditionals, loops, and formatting functions.

Multi-Container Template¶

When multiple containers are updated in a single cycle, the template receives a list:

{{range .Entries}}• {{.Name}}: {{.OldImage}} → {{.NewImage}}
{{end}}

Startup Message¶

By default, Updock sends a notification when it starts, confirming the webhook is working:

{
  "text": "Updock started monitoring 5 containers on host 'server-01'"
}

Disabling Startup Messages¶

Suppress the startup notification with --no-startup-message:

docker run -d \
  -e UPDOCK_WEBHOOK_URL="https://hooks.slack.com/services/xxx" \
  -e UPDOCK_NO_STARTUP_MESSAGE=true \
  -v /var/run/docker.sock:/var/run/docker.sock \
  updock/updock

Platform Examples¶

SlackDiscordMicrosoft TeamsCustom HTTP

UPDOCK_WEBHOOK_URL="https://hooks.slack.com/services/T00/B00/xxxxx"

Append /slack to use Discord's Slack-compatible endpoint:

UPDOCK_WEBHOOK_URL="https://discord.com/api/webhooks/123456/abcdef/slack"

UPDOCK_WEBHOOK_URL="https://outlook.office.com/webhook/xxxxx"

Any endpoint that accepts a JSON POST:

UPDOCK_WEBHOOK_URL="https://api.internal.example.com/updock-events"

Dry Run¶

When --dry-run is active, notifications include a [DRY RUN] prefix to indicate no actual updates were performed.