Fission MQT integration with keda (#1657)

Fission MQT integration based on Keda with Kafka connector

pkg/mqtrigger/util/util.go

@@ -0,0 +1,43 @@
+package util
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// FissionMetadata contains common fission side fields
+type FissionMetadata struct {
+	// fission
+	Topic         string
+	ResponseTopic string
+	ErrorTopic    string
+	FunctionURL   string
+	MaxRetries    int
+	ContentType   string
+	TriggerName   string
+}
+
+// ParseFissionMetadata parses fission side common fields and returns as fissionMetadata or returns error
+func ParseFissionMetadata() (FissionMetadata, error) {
+	for _, envVars := range []string{"TOPIC", "FUNCTION_URL", "MAX_RETRIES", "CONTENT_TYPE", "TRIGGER_NAME"} {
+		if os.Getenv(envVars) == "" {
+			return FissionMetadata{}, fmt.Errorf("environment variable not found: %v", envVars)
+		}
+	}
+	meta := FissionMetadata{
+		Topic:         os.Getenv("TOPIC"),
+		ResponseTopic: os.Getenv("RESPONSE_TOPIC"),
+		ErrorTopic:    os.Getenv("ERROR_TOPIC"),
+		FunctionURL:   os.Getenv("FUNCTION_URL"),
+		ContentType:   os.Getenv("CONTENT_TYPE"),
+		TriggerName:   os.Getenv("TRIGGER_NAME"),
+	}
+	val, err := strconv.ParseInt(strings.TrimSpace(os.Getenv("MAX_RETRIES")), 0, 64)
+	if err != nil {
+		return FissionMetadata{}, fmt.Errorf("failed to parse value from MAX_RETRIES environment variable %v", err)
+	}
+	meta.MaxRetries = int(val)
+	return meta, nil
+}