Alerting: Add validation to slack contact point (#45618)

* add requiredifempty

* rename field, fix logic

* update mockdata

* remove logs

* update test

* fix json expected payload in e2e tests

* fix test

* fix test again

Co-authored-by: Jean-Philippe Quémémer <jeanphilippe.quemener@grafana.com>

pkg/services/alerting/notifier.go

@@ -45,6 +45,7 @@ type NotifierOption struct {
 	Required       bool           `json:"required"`
 	ValidationRule string         `json:"validationRule"`
 	Secure         bool           `json:"secure"`
+	DependsOn      string         `json:"dependsOn"`
 }
 
 // InputType is the type of input that can be rendered in the frontend.

pkg/services/ngalert/notifier/available_channels.go

@@ -382,6 +382,8 @@ func GetAvailableNotifiers() []*alerting.NotifierPlugin {
 					InputType:    alerting.InputTypeText,
 					Description:  "Specify channel, private group, or IM channel (can be an encoded ID or a name) - required unless you provide a webhook",
 					PropertyName: "recipient",
+					Required:     true,
+					DependsOn:    "secureSettings.url",
 				},
 				// Logically, this field should be required when not using a webhook, since the Slack API needs a token.
 				// However, since the UI doesn't allow to say that a field is required or not depending on another field,
@@ -394,6 +396,8 @@ func GetAvailableNotifiers() []*alerting.NotifierPlugin {
 					Description:  "Provide a Slack API token (starts with \"xoxb\") - required unless you provide a webhook",
 					PropertyName: "token",
 					Secure:       true,
+					Required:     true,
+					DependsOn:    "secureSettings.url",
 				},
 				{
 					Label:        "Username",
@@ -458,6 +462,8 @@ func GetAvailableNotifiers() []*alerting.NotifierPlugin {
 					Placeholder:  "Slack incoming webhook URL",
 					PropertyName: "url",
 					Secure:       true,
+					Required:     true,
+					DependsOn:    "secureSettings.token",
 				},
 				{ // New in 8.4.
 					Label:        "Endpoint URL",