What causes "attribute %q is required" in hashicorp/terraform?

Add the required attribute to the backend block, e.g. `address = "https://state.example.com"`.

attribute %q is required

Error message

attribute %q is required

What it means

Returned by SDKLikeRequiredWithEnvDefault when, after checking the provided value and every fallback environment variable, the result is still empty. It is the SDK-style 'required attribute, possibly via env var' helper used by backends to enforce that a mandatory string attribute is supplied through config or environment — the attrPath is interpolated into the message to name the offending field.

Source

Thrown at internal/backend/backendbase/sdklike.go:155

			v = os.Getenv(envName)
			if v != "" {
				return v
			}
		}
	}
	return v
}

// SDKLikeRequiredWithEnvDefault is a convenience wrapper around
// [SDKLikeEnvDefault] which returns an error if the result is still the
// empty string even after trying all of the fallback environment variables.
//
// This wrapper requires an additional argument specifying the attribute name
// just because that becomes part of the returned error message.
func SDKLikeRequiredWithEnvDefault(attrPath string, v string, envNames ...string) (string, error) {
	ret := SDKLikeEnvDefault(v, envNames...)
	if ret == "" {
		return "", fmt.Errorf("attribute %q is required", attrPath)
	}
	return ret, nil
}

// SDKLikeDefaults captures legacy-SDK-like default values to help fill the
// gap in abstraction level between the legacy SDK and Terraform's own
// configuration schema model.
type SDKLikeDefaults map[string]SDKLikeDefault

type SDKLikeDefault struct {
	EnvVars  []string
	Fallback string

	// Required is for situations where an argument is optional to set
	// in the configuration but _must_ eventually be set through the
	// combination of the configuration and the environment variables
	// in this object.
	//

View on GitHub (pinned to c9def3e214)

Solutions

Add the required attribute to the backend block, e.g. `address = "https://state.example.com"`.
Export the documented fallback environment variable(s) for that attribute in your shell/CI.
Check the backend's docs for the exact env var names and set the appropriate one.
If the attribute should be optional, change the backend to call SDKLikeEnvDefault (non-required) or supply a fallback.

Example fix

// before
backend "http" {
  # address omitted, no TF_HTTP_ADDRESS env -> 'attribute "address" is required'
}
// after (option A: config)
backend "http" {
  address = "https://state.example.com"
}
// after (option B: env)
// export TF_HTTP_ADDRESS=https://state.example.com

Defensive patterns

Strategy: validation

Validate before calling

val, err := backendbase.SDKLikeRequiredWithEnvDefault("address", cfg.Address, "TF_HTTP_ADDRESS")
if err != nil {
    return fmt.Errorf("backend http: %w", err)
}

Type guard

func isRequiredAttrError(err error) bool {
    return err != nil && strings.Contains(err.Error(), "is required")
}

Try / catch

addr, err := backendbase.SDKLikeRequiredWithEnvDefault("address", v, "TF_HTTP_ADDRESS")
if err != nil {
    // instruct the user to set config or env var
    return fmt.Errorf("set 'address' in the backend block or TF_HTTP_ADDRESS in the environment: %w", err)
}

Prevention

Always set required backend string attributes in config or export the documented env vars.
Document which env vars each backend honors.
Validate required attributes at config-load time with a clear message.

When it happens

Trigger: Returned at internal/backend/backendbase/sdklike.go:155 when SDKLikeEnvDefault returns "". SDKLikeEnvDefault returns the value if non-empty, else the first non-empty env var among envNames, else "". So the error means: attribute unset in config AND none of the listed env vars are set.

Common situations: A required backend attribute is omitted from the backend block and no environment fallback is exported. e.g. an http backend missing `address` with no matching env var. Migrating a backend where the attribute used to be defaulted but is now required. CI that set TF_CLI_args but not the backend-specific env vars.

Related errors

AI-assisted analysis of hashicorp/terraform@c9def3e214 (2026-08-07). Data as JSON: /api/errors/ad3fa8158aee2817. Report an issue: GitHub.