Go Template if condition

Question

how can i combine and and eq/ne functions together?

I wrote this snippet

{{ define "opsgenie.default.tmpl" }}
  <font size="+0"><b>{{.CommonLabels.alertname }}</b></font>
  {{- range $i, $alert := .Alerts }}
  <font size="+0">{{ .Annotations.description }}</font>
  {{- end -}}
  {{- "\n" -}}
  {{- "\n" -}}
  {{- if and eq .CommonLabels.infoalert "true" eq .CommonLabels.topic "database" -}}
  Grafana: https://{{ .CommonLabels.url }}
  {{- "\n" -}}{{- end -}}
  {{- if and ne .CommonLabels.infoalert "true" eq .CommonLabels.topic "database" -}}
  Database:
    • https://{{ .CommonLabels.url }}/
    • https://{{ .CommonLabels.url }}/
  {{- "\n" -}}{{- end -}}
  {{- end -}}
  {{- end -}}
{{- end -}}

The goal is:

• if my alert contains both labels infoalert: true and topic: database then show only Grafana link
• if my alert contains only label topic: database but not infoalert: true then show only Databsse link

It looks like the syntax for condition {{- if and eq .CommonLabels.infoalert "true" eq .CommonLabels.topic "database" -}} is not correct because i get this error in alertmanager.log when alert is fired:

notify retry canceled due to unrecoverable error after 1 attempts: templating error: template: email.tmpl:24:17: executing \"opsgenie.default.tmpl\" at <eq>: wrong number of args for eq: want at least 1 got 0

Answer 1

Simply use parenthesis to group the expressions:

{{- if and (eq .CommonLabels.infoalert "true") (eq .CommonLabels.topic "database") -}}

{{- if and (ne .CommonLabels.infoalert "true") (eq .CommonLabels.topic "database") -}}

See this testable example:

func main() {
    t := template.Must(template.New("").Parse(src))

    m := map[string]any{
        "infoalert": "true",
        "topic":     "database",
    }
    if err := t.Execute(os.Stdout, m); err != nil {
        panic(err)
    }

    fmt.Println("Second round")
    m["infoalert"] = "false"
    if err := t.Execute(os.Stdout, m); err != nil {
        panic(err)
    }
}

const src = `
{{- if and (eq .infoalert "true") (eq .topic "database") -}}
    infoalert is true and topic is database
{{- end -}}
{{- if and (ne .infoalert "true") (eq .topic "database") -}}
    infoalert is NOT true and topic is database
{{ end }}
`

This will output (try it on the Go Playground):

infoalert is true and topic is database
Second round
infoalert is NOT true and topic is database