Monitor Only report notifications

[piksel]

The default report template does not work well with monitor-only, but here are some alternative ones you can use:

Version that always sends a report:

{{- with .Report -}}
  {{len .Scanned}} Scanned, {{len .Stale}} Stale, {{len .Failed}} Failed
        {{- range .Stale}}
  - {{.Name}} ({{.ImageName}}): {{.CurrentImageID.ShortID}} has a new image {{.LatestImageID.ShortID}}
        {{- end -}}
        {{- range .Fresh}}
  - {{.Name}} ({{.ImageName}}): {{.State}}
      {{- end -}}
      {{- range .Skipped}}
  - {{.Name}} ({{.ImageName}}): {{.State}}: {{.Error}}
      {{- end -}}
      {{- range .Failed}}
  - {{.Name}} ({{.ImageName}}): {{.State}}: {{.Error}}
      {{- end -}}
{{- end -}}
{{- if (and .Entries .Report) }}

Logs:
{{ end -}}
{{range .Entries -}}{{.Time.Format `2006-01-02T15:04:05Z07:00`}} [{{printf `%5.5s` .Level}}] {{.Message}}{{println}}{{- end -}}

Version that only sends notifications when noteworthy¹ things happened:

{{- with .Report -}}
  {{- if ( or .Stale .Failed ) -}}
    {{len .Scanned}} Scanned, {{len .Stale}} Stale, {{len .Failed}} Failed
      {{- range .Stale}}
  - {{.Name}} ({{.ImageName}}): {{.CurrentImageID.ShortID}} has a new image {{.LatestImageID.ShortID}}
      {{- end -}}
      {{- range .Fresh}}
  - {{.Name}} ({{.ImageName}}): {{.State}}
      {{- end -}}
      {{- range .Skipped}}
  - {{.Name}} ({{.ImageName}}): {{.State}}: {{.Error}}
      {{- end -}}
      {{- range .Failed}}
  - {{.Name}} ({{.ImageName}}): {{.State}}: {{.Error}}
      {{- end -}}
    {{- end -}}
  {{- end -}}
{{- if (and .Entries .Report (or .Report.Stale .Report.Failed)) }}

Logs:
{{ end -}}
{{- range .Entries -}}{{.Time.Format `2006-01-02T15:04:05Z07:00`}} [{{printf `%5.5s` .Level}}] {{.Message}}{{println}}{{- end -}}

See #1807 for an example of how to apply these templates in your docker-compose.yaml.

Footnotes

1. "Noteworthy" is defined as "Any containers where stale (has a newer image), or checking for updates for any containers failed", but this can of course be changed by altering the {{- if ( or .Stale .Failed ) -}} condition. Make sure to also make the same change to {{- if (and .Entries .Report (or .Report.Stale .Report.Failed)) }} to skip the logs: separator text between the summary and log entries when they are not both present. ↩