Merge pull request #208 from githubnext/copilot/remove-duplicate-code-validation

Author: pelikhan

internal/config/env_validation.go

@@ -8,6 +8,8 @@ import (
 	"regexp"
 	"strconv"
 	"strings"
+
+	"github.com/githubnext/gh-aw-mcpg/internal/config/rules"
 )
 
 // RequiredEnvVars lists the environment variables that must be set for the gateway to operate
@@ -272,8 +274,8 @@ func GetGatewayPortFromEnv() (int, error) {
 		return 0, fmt.Errorf("invalid MCP_GATEWAY_PORT value: %s", portStr)
 	}
 
-	if port < 1 || port > 65535 {
-		return 0, fmt.Errorf("MCP_GATEWAY_PORT must be between 1 and 65535, got %d", port)
+	if validationErr := rules.PortRange(port, "MCP_GATEWAY_PORT"); validationErr != nil {
+		return 0, fmt.Errorf("%s", validationErr.Message)
 	}
 
 	return port, nil

internal/config/rules/rules.go

@@ -0,0 +1,99 @@
+package rules
+
+import (
+	"fmt"
+	"strings"
+)
+
+// ValidationError represents a configuration validation error with context
+type ValidationError struct {
+	Field      string
+	Message    string
+	JSONPath   string
+	Suggestion string
+}
+
+func (e *ValidationError) Error() string {
+	var sb strings.Builder
+	sb.WriteString(fmt.Sprintf("Configuration error at %s: %s", e.JSONPath, e.Message))
+	if e.Suggestion != "" {
+		sb.WriteString(fmt.Sprintf("\nSuggestion: %s", e.Suggestion))
+	}
+	return sb.String()
+}
+
+// PortRange validates that a port is in the valid range (1-65535)
+// Returns nil if valid, *ValidationError if invalid
+func PortRange(port int, jsonPath string) *ValidationError {
+	if port < 1 || port > 65535 {
+		return &ValidationError{
+			Field:      "port",
+			Message:    fmt.Sprintf("port must be between 1 and 65535, got %d", port),
+			JSONPath:   jsonPath,
+			Suggestion: "Use a valid port number (e.g., 8080)",
+		}
+	}
+	return nil
+}
+
+// TimeoutPositive validates that a timeout value is at least 1
+// Returns nil if valid, *ValidationError if invalid
+func TimeoutPositive(timeout int, fieldName, jsonPath string) *ValidationError {
+	if timeout < 1 {
+		return &ValidationError{
+			Field:      fieldName,
+			Message:    fmt.Sprintf("%s must be at least 1, got %d", fieldName, timeout),
+			JSONPath:   jsonPath,
+			Suggestion: "Use a positive number of seconds (e.g., 30)",
+		}
+	}
+	return nil
+}
+
+// MountFormat validates a mount specification in the format "source:dest:mode"
+// Returns nil if valid, *ValidationError if invalid
+func MountFormat(mount, jsonPath string, index int) *ValidationError {
+	parts := strings.Split(mount, ":")
+	if len(parts) != 3 {
+		return &ValidationError{
+			Field:      "mounts",
+			Message:    fmt.Sprintf("invalid mount format '%s' (expected 'source:dest:mode')", mount),
+			JSONPath:   fmt.Sprintf("%s.mounts[%d]", jsonPath, index),
+			Suggestion: "Use format 'source:dest:mode' where mode is 'ro' (read-only) or 'rw' (read-write)",
+		}
+	}
+
+	source, dest, mode := parts[0], parts[1], parts[2]
+
+	// Validate source is not empty
+	if source == "" {
+		return &ValidationError{
+			Field:      "mounts",
+			Message:    fmt.Sprintf("mount source cannot be empty in '%s'", mount),
+			JSONPath:   fmt.Sprintf("%s.mounts[%d]", jsonPath, index),
+			Suggestion: "Provide a valid source path",
+		}
+	}
+
+	// Validate dest is not empty
+	if dest == "" {
+		return &ValidationError{
+			Field:      "mounts",
+			Message:    fmt.Sprintf("mount destination cannot be empty in '%s'", mount),
+			JSONPath:   fmt.Sprintf("%s.mounts[%d]", jsonPath, index),
+			Suggestion: "Provide a valid destination path",
+		}
+	}
+
+	// Validate mode
+	if mode != "ro" && mode != "rw" {
+		return &ValidationError{
+			Field:      "mounts",
+			Message:    fmt.Sprintf("invalid mount mode '%s' (must be 'ro' or 'rw')", mode),
+			JSONPath:   fmt.Sprintf("%s.mounts[%d]", jsonPath, index),
+			Suggestion: "Use 'ro' for read-only or 'rw' for read-write",
+		}
+	}
+
+	return nil
+}