feat(BRIDGE-236): added SMTP observability metrics

internal/services/smtp/observabilitymetrics/metrics.go

@@ -0,0 +1,90 @@
+// Copyright (c) 2024 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package observabilitymetrics
+
+import (
+	"time"
+
+	"github.com/ProtonMail/go-proton-api"
+)
+
+const (
+	smtpErrorsSchemaName    = "bridge_smtp_errors_total"
+	smtpErrorsSchemaVersion = 1
+
+	smtpSendSuccessSchemaName    = "bridge_smtp_send_success_total"
+	smtpSendSuccessSchemaVersion = 1
+)
+
+func generateSMTPErrorObservabilityMetric(errorType string) proton.ObservabilityMetric {
+	return proton.ObservabilityMetric{
+		Name:      smtpErrorsSchemaName,
+		Version:   smtpErrorsSchemaVersion,
+		Timestamp: time.Now().Unix(),
+		Data: map[string]interface{}{
+			"Value": 1,
+			"Labels": map[string]string{
+				"errorType": errorType,
+			},
+		},
+	}
+}
+
+func GenerateFailedGetParentID() proton.ObservabilityMetric {
+	return generateSMTPErrorObservabilityMetric("failedGetParentId")
+}
+
+func GenerateUnsupportedMIMEType() proton.ObservabilityMetric {
+	return generateSMTPErrorObservabilityMetric("unsupportedMIMEType")
+}
+
+func GenerateFailedCreateDraft() proton.ObservabilityMetric {
+	return generateSMTPErrorObservabilityMetric("failedToCreateDraft")
+}
+
+func GenerateFailedCreateAttachments() proton.ObservabilityMetric {
+	return generateSMTPErrorObservabilityMetric("failedCreateAttachments")
+}
+
+func GenerateFailedToGetRecipients() proton.ObservabilityMetric {
+	return generateSMTPErrorObservabilityMetric("failedGetRecipients")
+}
+
+func GenerateFailedCreatePackages() proton.ObservabilityMetric {
+	return generateSMTPErrorObservabilityMetric("failedCreatePackages")
+}
+
+func GenerateFailedSendDraft() proton.ObservabilityMetric {
+	return generateSMTPErrorObservabilityMetric("failedSendDraft")
+}
+
+func GenerateFailedDeleteFromDrafts() proton.ObservabilityMetric {
+	return generateSMTPErrorObservabilityMetric("failedDeleteFromDrafts")
+}
+
+func GenerateSMTPSendSuccess() proton.ObservabilityMetric {
+	return proton.ObservabilityMetric{
+		Name:      smtpSendSuccessSchemaName,
+		Version:   smtpSendSuccessSchemaVersion,
+		Timestamp: time.Now().Unix(),
+		Data: map[string]interface{}{
+			"Value":  1,
+			"Labels": map[string]string{},
+		},
+	}
+}