What causes "parse yaml: %w" in kataras/iris?

Inspect the wrapped (%w) cause in the error message — it names the actual underlying failure.

parse yaml: %w

Error message

parse yaml: %w

What it means

iris.parseYAML (configuration.go:64) wraps any error from filepath.Abs while resolving the configuration YAML path. The "parse yaml: %w" prefix is applied to all three failure stages (path resolution, file read, YAML unmarshal), so this instance specifically means the absolute-path resolution of the given filename failed — rare, and typically only when the path is malformed or the OS call fails. The error is returned (and typically panics) from iris.YAML or createGlobalConfiguration.

Source

Thrown at configuration.go:64

			home = os.Getenv("home")
		case "windows":
			home = os.Getenv("HOMEDRIVE") + os.Getenv("HOMEPATH")
			if home == "" {
				home = os.Getenv("USERPROFILE")
			}
		}
	}

	return
}

func parseYAML(filename string) (Configuration, error) {
	c := DefaultConfiguration()
	// get the abs
	// which will try to find the 'filename' from current workind dir too.
	yamlAbsPath, err := filepath.Abs(filename)
	if err != nil {
		return c, fmt.Errorf("parse yaml: %w", err)
	}

	// read the raw contents of the file
	data, err := os.ReadFile(yamlAbsPath)
	if err != nil {
		return c, fmt.Errorf("parse yaml: %w", err)
	}

	// put the file's contents as yaml to the default configuration(c)
	if err := yaml.Unmarshal(data, &c); err != nil {
		return c, fmt.Errorf("parse yaml: %w", err)
	}
	return c, nil
}

// YAML reads Configuration from a configuration.yml file.
//
// Accepts the absolute path of the cfg.yml.

View on GitHub (pinned to 7bedaf55a0)

Solutions

Inspect the wrapped (%w) cause in the error message — it names the actual underlying failure.
Verify the filename argument passed to iris.YAML is a non-empty, well-formed path.
Pre-resolve the path yourself with filepath.Abs/ExecDir and pass the absolute path.
If the real problem is a missing file, create the file or switch to the default configuration (don't call YAML at all — DefaultConfiguration is used implicitly).

Example fix

// before
conf := iris.YAML("") // empty path

// after
conf := iris.YAML("/etc/myapp/iris.yml") // explicit absolute path

Defensive patterns

Strategy: try-catch

Validate before calling

// filepath.Abs rarely fails, but guard the input:
func safeYAMLPath(filename string) (string, error) {
    if strings.TrimSpace(filename) == "" {
        return "", errors.New("empty iris config filename")
    }
    return filepath.Abs(filename)
}

Try / catch

// iris.YAML panics on error, so recover at startup:
func loadIrisConfig(path string) (conf iris.Configuration) {
    defer func() {
        if r := recover(); r != nil {
            log.Printf("iris yaml config failed (%v), using defaults", r)
            conf = iris.DefaultConfiguration()
        }
    }()
    return iris.YAML(path)
}

Prevention

Never pass empty or user-supplied unvalidated strings as the config path.
Pre-resolve and validate the path with filepath.Abs + os.Stat before calling iris.YAML.
Prefer absolute paths from a config directory constant over relative paths.
Distinguish this rare Abs failure from the common missing-file case by reading the wrapped error text.

When it happens

Trigger: Calling iris.YAML("myconfig.yml") or running with iris.WithGlobalConfiguration where filepath.Abs(filename) returns an error — e.g. an invalid path argument. Note: a non-existent file does NOT produce this variant; it produces the os.ReadFile variant (see error 54).

Common situations: Passing an empty or otherwise invalid path string to iris.YAML; unusual OS-level path errors. In practice this is the least common of the three "parse yaml" failures, since Abs rarely fails on Linux/Windows/macOS.

Related errors

AI-assisted analysis of kataras/iris@7bedaf55a0 (2026-08-30). Data as JSON: /api/errors/355c9c632baa044d. Report an issue: GitHub.