pulumi/pulumi · error

failed to read Pulumi config file '%s': %w

Error message

failed to read Pulumi config file '%s': %w

What it means

This error means the Pulumi config file was read successfully but its contents could not be parsed into PulumiConfig via json.Unmarshal. The library throws it so a malformed config is surfaced instead of being silently overwritten with BackendConfig cleared.

Source

Thrown at sdk/go/common/workspace/creds.go:1172

// deleteAllBackendConfig removes all backend configuration from the default
// config file.
func deleteAllBackendConfig() error {
	configFile, err := getConfigFilePath()
	if err != nil {
		return err
	}
	data, err := os.ReadFile(configFile)
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return fmt.Errorf("reading '%s': %w", configFile, err)
	}

	var config PulumiConfig
	if err = json.Unmarshal(data, &config); err != nil {
		return fmt.Errorf("failed to read Pulumi config file '%s': %w", configFile, err)
	}
	config.BackendConfig = nil
	return writePulumiConfigFile(configFile, config)
}

type BackendConfig struct {
	DefaultOrg string `json:"defaultOrg,omitempty"` // The default org for this backend config.
}

type PulumiConfig struct {
	BackendConfig map[string]BackendConfig `json:"backends,omitempty"` // a map of arbitrary backends configs.
}

func getConfigFilePath() (string, error) {
	// Allow the folder we use to store config in to be overridden by tests
	pulumiFolder := os.Getenv(PulumiCredentialsPathEnvVar)
	if pulumiFolder == "" {
		logging.V(7).Infof("Using default Pulumi config path")

View on GitHub (pinned to 793f7b2e16)

Solutions

1. Run the file through `jq . <configFile>` to find and fix the JSON syntax error
2. Restore from backup or delete the file and let pulumi regenerate it
3. Remove JSON comments and trailing commas — the parser is strict encoding/json
4. If types are wrong (e.g. backendConfig not an object), correct the JSON structure to match PulumiConfig

Example fix

// before
{ "backendConfig": "https://api.pulumi.com" }
// after
{ "backendConfig": { "url": "https://api.pulumi.com" } }

data, err := os.ReadFile(configFile)
if err != nil { return err }
data = bytes.TrimPrefix(data, []byte{0xEF, 0xBB, 0xBF})
var probe PulumiConfig
if err := json.Unmarshal(data, &probe); err != nil {
    return fmt.Errorf("invalid Pulumi config JSON: %w", err)
}

When it happens

Trigger: The config file contains invalid JSON or JSON with unexpected types for PulumiConfig fields (e.g. backendConfig as a string instead of object), causing json.Unmarshal to fail.

Common situations: Manual editing introduced a trailing comma or comments (JSON has neither); file truncated by a crash; file written by an older/different tool version with a divergent schema.

Related errors

• failed to read Pulumi agent config file '%s': %w
• failed to read Pulumi config file: %w
• could not parse file %s: %w
• marshalling config object: %w
• unmarshaling deployment: %w

AI-assisted analysis of pulumi/pulumi@793f7b2e16 (2026-08-31). Data as JSON: /api/errors/50460df3615fa6d9. Report an issue: GitHub.