feat: slack default color from template

Signed-off-by: Michael Kanchuker <michaelkanchuker@gmail.com>

Author: mkl262

asset/assets_vfsdata.go

@@ -94,7 +94,7 @@ var (
 		NotifierConfig: NotifierConfig{
 			VSendResolved: false,
 		},
-		Color:      `{{ if eq .Status "firing" }}danger{{ else }}good{{ end }}`,
+		Color:      `{{ template "slack.default.color" . }}`,
 		Username:   `{{ template "slack.default.username" . }}`,
 		Title:      `{{ template "slack.default.title" . }}`,
 		TitleLink:  `{{ template "slack.default.titlelink" . }}`,

config/notifiers.go

@@ -1436,15 +1436,15 @@ The notification contains an [attachment](https://api.slack.com/messaging/compos
 channel: <tmpl_string>
 
 # API request data as defined by the Slack webhook API.
-[ icon_emoji: <tmpl_string> ]
-[ icon_url: <tmpl_string> ]
+[ icon_emoji: <tmpl_string> | default = '{{ template "slack.default.iconemoji" . }}' ]
+[ icon_url: <tmpl_string> | default = '{{ template "slack.default.iconurl" . }}' ]
 [ link_names: <boolean> | default = false ]
 [ username: <tmpl_string> | default = '{{ template "slack.default.username" . }}' ]
 # The following parameters define the attachment.
 actions:
   [ <action_config> ... ]
 [ callback_id: <tmpl_string> | default = '{{ template "slack.default.callbackid" . }}' ]
-[ color: <tmpl_string> | default = '{{ if eq .Status "firing" }}danger{{ else }}good{{ end }}' ]
+[ color: <tmpl_string> | default = '{{ template "slack.default.color" . }}' ]
 [ fallback: <tmpl_string> | default = '{{ template "slack.default.fallback" . }}' ]
 fields:
   [ <field_config> ... ]

docs/configuration.md

@@ -32,6 +32,7 @@ Source: {{ .GeneratorURL }}
 {{ define "slack.default.iconurl" }}{{ end }}
 {{ define "slack.default.text" }}{{ end }}
 {{ define "slack.default.footer" }}{{ end }}
+{{ define "slack.default.color" }}{{ if eq .Status "firing" }}danger{{ else }}good{{ end }}{{ end }}
 
 
 {{ define "pagerduty.default.description" }}{{ template "__subject" . }}{{ end }}