Improve error handling for validator

- Surface error codes for datasource possible errors (not found, unreachabel, auth, timeout)
2026-01-06 13:27:34 +01:00
parent f81deced02
commit 01f959be97
5 changed files with 600 additions and 23 deletions
@@ -0,0 +1,173 @@
+package validator
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+)
+
+// ErrorCode represents the type of error that occurred
+type ErrorCode string
+
+const (
+	// Datasource-related errors
+	ErrCodeDatasourceNotFound    ErrorCode = "datasource_not_found"
+	ErrCodeDatasourceWrongType   ErrorCode = "datasource_wrong_type"
+	ErrCodeDatasourceUnreachable ErrorCode = "datasource_unreachable"
+	ErrCodeDatasourceAuth        ErrorCode = "datasource_auth_failed"
+	ErrCodeDatasourceConfig      ErrorCode = "datasource_config_error"
+
+	// API-related errors
+	ErrCodeAPIUnavailable     ErrorCode = "api_unavailable"
+	ErrCodeAPIInvalidResponse ErrorCode = "api_invalid_response"
+	ErrCodeAPIRateLimit       ErrorCode = "api_rate_limit"
+	ErrCodeAPITimeout         ErrorCode = "api_timeout"
+
+	// Validation errors
+	ErrCodeInvalidDashboard       ErrorCode = "invalid_dashboard"
+	ErrCodeUnsupportedDashVersion ErrorCode = "unsupported_dashboard_version"
+	ErrCodeInvalidQuery           ErrorCode = "invalid_query"
+
+	// Internal errors
+	ErrCodeInternal ErrorCode = "internal_error"
+)
+
+// ValidationError represents a structured error with context
+type ValidationError struct {
+	Code       ErrorCode
+	Message    string
+	Details    map[string]interface{}
+	StatusCode int
+	Cause      error
+}
+
+// Error implements the error interface
+func (e *ValidationError) Error() string {
+	if e.Cause != nil {
+		return fmt.Sprintf("%s: %s (caused by: %v)", e.Code, e.Message, e.Cause)
+	}
+	return fmt.Sprintf("%s: %s", e.Code, e.Message)
+}
+
+// Unwrap implements error unwrapping
+func (e *ValidationError) Unwrap() error {
+	return e.Cause
+}
+
+// NewValidationError creates a new ValidationError
+func NewValidationError(code ErrorCode, message string, statusCode int) *ValidationError {
+	return &ValidationError{
+		Code:       code,
+		Message:    message,
+		StatusCode: statusCode,
+		Details:    make(map[string]interface{}),
+	}
+}
+
+// WithCause adds the underlying error cause
+func (e *ValidationError) WithCause(err error) *ValidationError {
+	e.Cause = err
+	return e
+}
+
+// WithDetail adds contextual information
+func (e *ValidationError) WithDetail(key string, value interface{}) *ValidationError {
+	e.Details[key] = value
+	return e
+}
+
+// Common error constructors
+
+// NewDatasourceNotFoundError creates an error for datasource not found
+func NewDatasourceNotFoundError(uid string, namespace string) *ValidationError {
+	return NewValidationError(
+		ErrCodeDatasourceNotFound,
+		fmt.Sprintf("datasource not found: %s", uid),
+		http.StatusNotFound,
+	).WithDetail("datasourceUID", uid).WithDetail("namespace", namespace)
+}
+
+// NewDatasourceWrongTypeError creates an error for wrong datasource type
+func NewDatasourceWrongTypeError(uid string, expectedType string, actualType string) *ValidationError {
+	return NewValidationError(
+		ErrCodeDatasourceWrongType,
+		fmt.Sprintf("datasource %s has wrong type: expected %s, got %s", uid, expectedType, actualType),
+		http.StatusBadRequest,
+	).WithDetail("datasourceUID", uid).
+		WithDetail("expectedType", expectedType).
+		WithDetail("actualType", actualType)
+}
+
+// NewDatasourceUnreachableError creates an error for unreachable datasource
+func NewDatasourceUnreachableError(uid string, url string, cause error) *ValidationError {
+	return NewValidationError(
+		ErrCodeDatasourceUnreachable,
+		fmt.Sprintf("datasource %s at %s is unreachable", uid, url),
+		http.StatusServiceUnavailable,
+	).WithDetail("datasourceUID", uid).
+		WithDetail("url", url).
+		WithCause(cause)
+}
+
+// NewAPIUnavailableError creates an error for unavailable API
+func NewAPIUnavailableError(statusCode int, responseBody string, cause error) *ValidationError {
+	return NewValidationError(
+		ErrCodeAPIUnavailable,
+		fmt.Sprintf("Prometheus API returned status %d", statusCode),
+		http.StatusBadGateway,
+	).WithDetail("upstreamStatus", statusCode).
+		WithDetail("responseBody", responseBody).
+		WithCause(cause)
+}
+
+// NewAPIInvalidResponseError creates an error for invalid API response
+func NewAPIInvalidResponseError(message string, cause error) *ValidationError {
+	return NewValidationError(
+		ErrCodeAPIInvalidResponse,
+		fmt.Sprintf("Prometheus API returned invalid response: %s", message),
+		http.StatusBadGateway,
+	).WithCause(cause)
+}
+
+// NewAPITimeoutError creates an error for API timeout
+func NewAPITimeoutError(url string, cause error) *ValidationError {
+	return NewValidationError(
+		ErrCodeAPITimeout,
+		fmt.Sprintf("request to %s timed out", url),
+		http.StatusGatewayTimeout,
+	).WithDetail("url", url).
+		WithCause(cause)
+}
+
+// NewDatasourceAuthError creates an error for authentication failures
+func NewDatasourceAuthError(uid string, statusCode int) *ValidationError {
+	return NewValidationError(
+		ErrCodeDatasourceAuth,
+		fmt.Sprintf("authentication failed for datasource %s (status %d)", uid, statusCode),
+		http.StatusUnauthorized,
+	).WithDetail("datasourceUID", uid).
+		WithDetail("upstreamStatus", statusCode)
+}
+
+// IsValidationError checks if an error is a ValidationError
+func IsValidationError(err error) bool {
+	var validationErr *ValidationError
+	return errors.As(err, &validationErr)
+}
+
+// GetValidationError extracts a ValidationError from an error chain
+func GetValidationError(err error) *ValidationError {
+	var validationErr *ValidationError
+	if errors.As(err, &validationErr) {
+		return validationErr
+	}
+	return nil
+}
+
+// GetHTTPStatusCode returns the appropriate HTTP status code for an error
+func GetHTTPStatusCode(err error) int {
+	if validationErr := GetValidationError(err); validationErr != nil {
+		return validationErr.StatusCode
+	}
+	return http.StatusInternalServerError
+}