initial

pkg/config/resolver.go

@@ -0,0 +1,204 @@
+package config
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	secretmanager "cloud.google.com/go/secretmanager/apiv1"
+	"cloud.google.com/go/secretmanager/apiv1/secretmanagerpb"
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-sdk-go/service/secretsmanager"
+	"github.com/spf13/afero"
+)
+
+// Resolver handles resolution of configuration values with special prefixes.
+type Resolver struct {
+	gcpProject   string
+	awsRegion    string
+	gsmClient    *secretmanager.Client
+	asmClient    *secretsmanager.SecretsManager
+	awsSession   *session.Session
+	specialValue *regexp.Regexp
+	fs           afero.Fs
+}
+
+// NewResolver creates a new value resolver.
+func NewResolver(gcpProject, awsRegion string, fs afero.Fs) *Resolver {
+	return &Resolver{
+		gcpProject:   gcpProject,
+		awsRegion:    awsRegion,
+		specialValue: regexp.MustCompile(`^\$([A-Z]+):(.+)$`),
+		fs:           fs,
+	}
+}
+
+// Resolve resolves a configuration value that may contain special prefixes.
+func (r *Resolver) Resolve(value interface{}) interface{} {
+	switch v := value.(type) {
+	case string:
+		return r.resolveString(v)
+	case map[string]interface{}:
+		// Recursively resolve map values
+		result := make(map[string]interface{})
+		for k, val := range v {
+			result[k] = r.Resolve(val)
+		}
+		return result
+	case []interface{}:
+		// Recursively resolve slice items
+		result := make([]interface{}, len(v))
+		for i, val := range v {
+			result[i] = r.Resolve(val)
+		}
+		return result
+	default:
+		// Return non-string values as-is
+		return value
+	}
+}
+
+// resolveString resolves a string value that may contain a special prefix.
+func (r *Resolver) resolveString(value string) interface{} {
+	matches := r.specialValue.FindStringSubmatch(value)
+	if matches == nil {
+		return value
+	}
+
+	resolverType := matches[1]
+	resolverValue := matches[2]
+
+	switch resolverType {
+	case "ENV":
+		return r.resolveEnv(resolverValue)
+	case "GSM":
+		return r.resolveGSM(resolverValue)
+	case "ASM":
+		return r.resolveASM(resolverValue)
+	case "FILE":
+		return r.resolveFile(resolverValue)
+	default:
+		log.Printf("Unknown resolver type: %s", resolverType)
+		return value
+	}
+}
+
+// resolveEnv resolves an environment variable.
+func (r *Resolver) resolveEnv(envVar string) interface{} {
+	value := os.Getenv(envVar)
+	if value == "" {
+		return nil
+	}
+	return value
+}
+
+// resolveGSM resolves a Google Secret Manager secret.
+func (r *Resolver) resolveGSM(secretName string) interface{} {
+	if r.gcpProject == "" {
+		log.Printf("GCP project not configured for GSM resolution")
+		return nil
+	}
+
+	// Initialize GSM client if needed
+	if r.gsmClient == nil {
+		ctx := context.Background()
+		client, err := secretmanager.NewClient(ctx)
+		if err != nil {
+			log.Printf("Failed to create GSM client: %v", err)
+			return nil
+		}
+		r.gsmClient = client
+	}
+
+	// Build the resource name
+	name := fmt.Sprintf("projects/%s/secrets/%s/versions/latest", r.gcpProject, secretName)
+
+	// Access the secret
+	ctx := context.Background()
+	req := &secretmanagerpb.AccessSecretVersionRequest{
+		Name: name,
+	}
+
+	result, err := r.gsmClient.AccessSecretVersion(ctx, req)
+	if err != nil {
+		log.Printf("Failed to access GSM secret %s: %v", secretName, err)
+		return nil
+	}
+
+	return string(result.Payload.Data)
+}
+
+// resolveASM resolves an AWS Secrets Manager secret.
+func (r *Resolver) resolveASM(secretName string) interface{} {
+	// Initialize AWS session if needed
+	if r.awsSession == nil {
+		sess, err := session.NewSession(&aws.Config{
+			Region: aws.String(r.awsRegion),
+		})
+		if err != nil {
+			log.Printf("Failed to create AWS session: %v", err)
+			return nil
+		}
+		r.awsSession = sess
+	}
+
+	// Initialize ASM client if needed
+	if r.asmClient == nil {
+		r.asmClient = secretsmanager.New(r.awsSession)
+	}
+
+	// Get the secret value
+	input := &secretsmanager.GetSecretValueInput{
+		SecretId: aws.String(secretName),
+	}
+
+	result, err := r.asmClient.GetSecretValue(input)
+	if err != nil {
+		log.Printf("Failed to access ASM secret %s: %v", secretName, err)
+		return nil
+	}
+
+	// Return the secret string
+	if result.SecretString != nil {
+		return *result.SecretString
+	}
+
+	// If it's binary data, we can't handle it as a string config value
+	log.Printf("ASM secret %s contains binary data, which is not supported", secretName)
+	return nil
+}
+
+// resolveFile resolves a file's contents.
+func (r *Resolver) resolveFile(filePath string) interface{} {
+	// Expand user home directory if present
+	if strings.HasPrefix(filePath, "~/") {
+		home, err := os.UserHomeDir()
+		if err != nil {
+			log.Printf("Failed to get user home directory: %v", err)
+			return nil
+		}
+		filePath = filepath.Join(home, filePath[2:])
+	}
+
+	data, err := afero.ReadFile(r.fs, filePath)
+	if err != nil {
+		log.Printf("Failed to read file %s: %v", filePath, err)
+		return nil
+	}
+
+	// Strip whitespace/newlines from file contents
+	return strings.TrimSpace(string(data))
+}
+
+// Close closes any open clients.
+func (r *Resolver) Close() error {
+	if r.gsmClient != nil {
+		return r.gsmClient.Close()
+	}
+	return nil
+}