[monitoring] add settings alert for slack (#1545)

**What this PR does**
This PR adds configuration for sending alerts from Alerta to Slack.

**Key changes**
Added Slack integration configuration in Alerta settings.

packages/extra/monitoring/README.md

@@ -72,6 +72,8 @@
 | `alerta.alerts.telegram.token`            | Telegram token for your bot                                                         | `string`    | `""`    |
 | `alerta.alerts.telegram.chatID`           | Specify multiple ID's separated by comma. Get yours in https://t.me/chatid_echo_bot | `string`    | `""`    |
 | `alerta.alerts.telegram.disabledSeverity` | List of severity without alerts, separated by comma like: "informational,warning"   | `string`    | `""`    |
+| `alerta.alerts.slack`                     | Configuration for Slack alerts                                                      | `*object`   | `null`  |
+| `alerta.alerts.slack.url`                 | Configuration uri for Slack alerts                                                  | `*string`   | `""`    |
 
 
 ### Grafana configuration

packages/extra/monitoring/templates/alerta/alerta.yaml

@@ -109,9 +109,20 @@ spec:
             - name: AUTH_REQUIRED
               value: "True"
 
+            {{- $plugins := list }}
             {{- if and .Values.alerta.alerts.telegram.chatID .Values.alerta.alerts.telegram.token }}
+              {{- $plugins = append $plugins "telegram" }}
+            {{- end }}
+            {{- if .Values.alerta.alerts.slack.url }}
+              {{- $plugins = append $plugins "slack" }}
+            {{- end }}
+
+            {{- if gt (len $plugins) 0 }}
             - name: "PLUGINS"
-              value: "telegram"
+              value: "{{ default "" (join "," $plugins) }}"
+            {{- end }}
+
+            {{- if and .Values.alerta.alerts.telegram.chatID .Values.alerta.alerts.telegram.token }}
             - name: TELEGRAM_CHAT_ID
               value: "{{ .Values.alerta.alerts.telegram.chatID }}"
             - name: TELEGRAM_TOKEN
@@ -122,6 +133,11 @@ spec:
               value: "{{ .Values.alerta.alerts.telegram.disabledSeverity }}"
             {{- end }}
 
+            {{- if .Values.alerta.alerts.slack.url }}
+            - name: "SLACK_WEBHOOK_URL"
+              value: "{{ .Values.alerta.alerts.slack.url }}"
+            {{- end }}
+
           ports:
             - name: http
               containerPort: 8080

packages/extra/monitoring/values.schema.json

@@ -12,6 +12,17 @@
           "type": "object",
           "default": {},
           "properties": {
+            "slack": {
+              "description": "Configuration for Slack alerts",
+              "type": "object",
+              "default": {},
+              "properties": {
+                "url": {
+                  "description": "Configuration uri for Slack alerts",
+                  "type": "string"
+                }
+              }
+            },
             "telegram": {
               "description": "Configuration for Telegram alerts",
               "type": "object",

packages/extra/monitoring/values.yaml

@@ -90,6 +90,8 @@ logsStorages:
 ## @field telegramAlerts.token {string} Telegram token for your bot
 ## @field telegramAlerts.chatID {string} Specify multiple ID's separated by comma. Get yours in https://t.me/chatid_echo_bot
 ## @field telegramAlerts.disabledSeverity {string} List of severity without alerts, separated by comma like: "informational,warning"
+## @field alerts.slack {*slackAlerts} Configuration for Slack alerts
+## @field slackAlerts.url {*string} Configuration uri for Slack alerts
 alerta:
   storage: 10Gi
   storageClassName: ""
@@ -112,6 +114,9 @@ alerta:
       chatID: ""
       disabledSeverity: ""
 
+    slack:
+      url: ""
+
 ## @section Grafana configuration
 
 ## @param grafana {grafana} Configuration for Grafana