Fix issues with Slack contact points (#40953)

* recipient validation regex modified, validation at creation/modification implemented

* Remove validation for recipient, fix tests

* Log level changed from Warn to Error

pkg/services/ngalert/notifier/available_channels.go

@@ -380,7 +380,7 @@ func GetAvailableNotifiers() []*alerting.NotifierPlugin {
 					Label:        "Recipient",
 					Element:      alerting.ElementTypeInput,
 					InputType:    alerting.InputTypeText,
-					Description:  "Specify channel or user, use #channel-name, @username (has to be all lowercase, no whitespace), or user/channel Slack ID - required unless you provide a webhook",
+					Description:  "Specify channel, private group, or IM channel (can be an encoded ID or a name) - required unless you provide a webhook",
 					PropertyName: "recipient",
 				},
 				// Logically, this field should be required when not using a webhook, since the Slack API needs a token.

pkg/services/ngalert/notifier/channels/slack.go

@@ -10,7 +10,6 @@ import (
 	"net"
 	"net/http"
 	"net/url"
-	"regexp"
 	"strings"
 	"time"
 
@@ -42,8 +41,6 @@ type SlackNotifier struct {
 	Token          string
 }
 
-var reRecipient *regexp.Regexp = regexp.MustCompile("^((@[a-z0-9][a-zA-Z0-9._-]*)|(#[^ .A-Z]{1,79})|([a-zA-Z0-9]+))$")
-
 var SlackAPIEndpoint = "https://slack.com/api/chat.postMessage"
 
 // NewSlackNotifier is the constructor for the Slack notifier
@@ -62,11 +59,7 @@ func NewSlackNotifier(model *NotificationChannelConfig, t *template.Template, fn
 	}
 
 	recipient := strings.TrimSpace(model.Settings.Get("recipient").MustString())
-	if recipient != "" {
-		if !reRecipient.MatchString(recipient) {
-			return nil, receiverInitError{Cfg: *model, Reason: fmt.Sprintf("recipient on invalid format: %q", recipient)}
-		}
-	} else if apiURL.String() == SlackAPIEndpoint {
+	if recipient == "" && apiURL.String() == SlackAPIEndpoint {
 		return nil, receiverInitError{Cfg: *model,
 			Reason: "recipient must be specified when using the Slack chat API",
 		}
@@ -219,23 +212,25 @@ var sendSlackRequest = func(request *http.Request, logger log.Logger) error {
 	}
 
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
-		logger.Warn("Slack API request failed", "url", request.URL.String(), "statusCode", resp.Status, "body", string(body))
+		logger.Error("Slack API request failed", "url", request.URL.String(), "statusCode", resp.Status, "body", string(body))
 		return fmt.Errorf("request to Slack API failed with status code %d", resp.StatusCode)
 	}
 
-	// Slack responds to some requests with a JSON document, that might contain an error
+	// Slack responds to some requests with a JSON document, that might contain an error.
 	rslt := struct {
 		Ok  bool   `json:"ok"`
 		Err string `json:"error"`
 	}{}
-	if err := json.Unmarshal(body, &rslt); err != nil {
-		logger.Warn("Failed to unmarshal Slack API response", "url", request.URL.String(), "statusCode", resp.Status,
+
+	// Marshaling can fail if Slack's response body is plain text (e.g. "ok").
+	if err := json.Unmarshal(body, &rslt); err != nil && json.Valid(body) {
+		logger.Error("Failed to unmarshal Slack API response", "url", request.URL.String(), "statusCode", resp.Status,
 			"body", string(body))
 		return fmt.Errorf("failed to unmarshal Slack API response: %s", err)
 	}
 
 	if !rslt.Ok && rslt.Err != "" {
-		logger.Warn("Sending Slack API request failed", "url", request.URL.String(), "statusCode", resp.Status,
+		logger.Error("Sending Slack API request failed", "url", request.URL.String(), "statusCode", resp.Status,
 			"err", rslt.Err)
 		return fmt.Errorf("failed to make Slack API request: %s", rslt.Err)
 	}

pkg/services/ngalert/notifier/channels/slack_test.go

@@ -270,9 +270,8 @@ func TestSendSlackRequest(t *testing.T) {
 			expectError: false,
 		},
 		{
-			name:        "No response body",
-			statusCode:  http.StatusOK,
-			expectError: true,
+			name:       "No response body",
+			statusCode: http.StatusOK,
 		},
 		{
 			name:          "Success case, unexpected response body",