Improve secret handling by logging missing secrets and deduplicating … (docker#95)

* Improve secret handling by logging missing secrets and deduplicating secret names

* Refactor secret deduplication to use struct for improved memory efficiency

Author: Roman Wu

cmd/docker-mcp/internal/gateway/clientpool.go

@@ -272,6 +272,7 @@ func (cp *clientPool) argsAndEnv(serverConfig *catalog.ServerConfig, readOnly *b
 		if ok {
 			env = append(env, fmt.Sprintf("%s=%s", s.Env, secretValue))
 		} else {
+			logf("Warning: Secret '%s' not found for server '%s', setting %s=<UNKNOWN>", s.Name, serverConfig.Name, s.Env)
 			env = append(env, fmt.Sprintf("%s=%s", s.Env, "<UNKNOWN>"))
 		}
 	}

cmd/docker-mcp/internal/gateway/configuration.go

@@ -392,7 +392,9 @@ func (c *FileBasedConfiguration) readToolsConfig(ctx context.Context) (config.To
 }
 
 func (c *FileBasedConfiguration) readDockerDesktopSecrets(ctx context.Context, servers map[string]catalog.Server, serverNames []string) (map[string]string, error) {
-	var secretNames []string
+	// Use a map to deduplicate secret names
+	uniqueSecretNames := make(map[string]struct{})
+
 	for _, serverName := range serverNames {
 		serverName := strings.TrimSpace(serverName)
 
@@ -402,14 +404,20 @@ func (c *FileBasedConfiguration) readDockerDesktopSecrets(ctx context.Context, s
 		}
 
 		for _, s := range serverSpec.Secrets {
-			secretNames = append(secretNames, s.Name)
+			uniqueSecretNames[s.Name] = struct{}{}
 		}
 	}
 
-	if len(secretNames) == 0 {
+	if len(uniqueSecretNames) == 0 {
 		return map[string]string{}, nil
 	}
 
+	// Convert map keys to slice
+	var secretNames []string
+	for name := range uniqueSecretNames {
+		secretNames = append(secretNames, name)
+	}
+
 	log("  - Reading secrets", secretNames)
 	secretsByName, err := c.docker.ReadSecrets(ctx, secretNames, true)
 	if err != nil {