feat: Add utility function to check for duplicates in environment variables

PiperOrigin-RevId: 817616522

Author: cloud-deploy-samples-bot

packages/cdenv/cdenv.go

@@ -1,6 +1,12 @@
-// Package cdenv contains Cloud Deploy environment variable keys.
+// Package cdenv contains Cloud Deploy environment variable keys and utility functions for environment
+// variables.
 package cdenv
 
+import (
+	"fmt"
+	"strings"
+)
+
 // Cloud Deploy environment variable keys.
 const (
 	RequestTypeEnvKey = "CLOUD_DEPLOY_REQUEST_TYPE"
@@ -30,3 +36,37 @@ const (
 	CloudBuildServiceAccount = "CLOUD_DEPLOY_WP_CB_ServiceAccount"
 	CloudBuildWorkerPool     = "CLOUD_DEPLOY_WP_CB_WorkerPool"
 )
+
+// CheckDuplicates expects environment variables in the k=v format. It
+// converts the environment string slice to a map and checks for duplicates
+// and malformed entries.
+func CheckDuplicates(environ []string) (map[string]string, error) {
+	envMap := make(map[string]string)
+
+	if len(environ) == 0 {
+		return nil, fmt.Errorf("no environment variables found")
+	}
+
+	for _, envVar := range environ {
+		pair := strings.SplitN(envVar, "=", 2)
+		if len(pair) != 2 {
+			return nil, fmt.Errorf("incorrect env variable format - expected k=v")
+		}
+
+		key := pair[0]
+		value := pair[1]
+		if key == "" {
+			return nil, fmt.Errorf("empty environment variable key")
+		}
+
+		if value == "" {
+			return nil, fmt.Errorf("empty environment variable value")
+		}
+
+		if _, exists := envMap[strings.ToLower(key)]; exists {
+			return nil, fmt.Errorf("duplicate environment variable key: %s", key)
+		}
+		envMap[strings.ToLower(key)] = value
+	}
+	return envMap, nil
+}

packages/cdenv/cdenv_test.go

@@ -0,0 +1,97 @@
+package cdenv
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestCheckDuplicatesValid(t *testing.T) {
+	tests := []struct {
+		name     string
+		envVars  []string
+		wantVars map[string]string
+	}{
+		{
+			name: "Valid environment variables",
+			envVars: []string{
+				"KEY1=VALUE1",
+				"KEY2=VALUE2",
+			},
+			wantVars: map[string]string{
+				"key1": "VALUE1",
+				"key2": "VALUE2",
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			vars, err := CheckDuplicates(test.envVars)
+			if err != nil {
+				t.Errorf("checkDuplicates() error = %v", err)
+			}
+			if diff := cmp.Diff(vars, test.wantVars); diff != "" {
+				t.Errorf("checkDuplicates() mismatch (-want +got):\n%s", diff)
+			}
+		})
+	}
+}
+
+func TestCheckDuplicatesInvalid(t *testing.T) {
+	tests := []struct {
+		name    string
+		envVars []string
+	}{
+		{
+			name: "Empty environment variables",
+			envVars: []string{
+				"",
+				"",
+			},
+		},
+		{
+			name: "Duplicate environment variable with same case",
+			envVars: []string{
+				"KEY1=VALUE1",
+				"KEY1=VALUE2",
+			},
+		},
+		{
+			name: "Duplicate environment variable with different cases",
+			envVars: []string{
+				"KEY1=VALUE1",
+				"key1=VALUE2",
+			},
+		},
+		{
+			name: "Empty environment variable value",
+			envVars: []string{
+				"KEY1VALUE1=",
+				"KEY2=VALUE2",
+			},
+		},
+		{
+			name: "Empty environment variable key",
+			envVars: []string{
+				"=KEY1VALUE1",
+				"KEY2=VALUE2",
+			},
+		},
+		{
+			name: "Incorrect env variable format - expected k=v",
+			envVars: []string{
+				"KEY1VALUE1",
+				"KEY2=VALUE2",
+			},
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			_, err := CheckDuplicates(test.envVars)
+			if err == nil {
+				t.Errorf("checkDuplicates() error = nil, want error")
+			}
+		})
+	}
+}