Why does Membrane API Gateway return 500 for a request with an internal:// target?

Membrane could not hand the request to the internal API named in the internal:// target. Usually no API has exactly that name, the name refers to a proxy that is not a service API, or the destination is not a valid URI.

How do I fix No api found for destination in Membrane?

Make sure the name after internal:// matches the name of an internal API or another service API in the same configuration, including upper and lower case.

How do I hide the details in Membrane error responses?

Enable production mode by adding a configuration document with production: true to your apis.yaml. Membrane then leaves out detailed information from error responses.

500 Internal Server Error: Internal Routing Failed

Membrane API Gateway returns 500 Internal Server Error with this page when a request is routed to an internal:// target and Membrane cannot hand it to the internal API it names. The cause is usually the gateway configuration.

The Error Response

The response contains the status 500 Internal Server Error, the problem type https://membrane-api.io/problems/internal and a link to this page. In development mode it also contains the exception message, e.g. No api found for destination .... The type internal means that the gateway could not complete the processing of the request. In production mode, the title is replaced by Internal Server Error and the details are left out.

How Internal Routing Works

An API can forward a request to another API in the same gateway instead of a backend. The target url is then internal:// followed by the name of the other API:

api:
  port: 2000
  target:
    url: internal://shop
---
internal:
  name: shop
  flow:
    - return:
        status: 200

api:
  port: 2000
  target:
    url: internal://shop
---
internal:
  name: shop
  flow:
    - return:
        status: 200

Common Causes

No API Has That Name

No API has exactly the name in the internal://<name> target. The comparison is case-sensitive, so internal://Shop does not find an API named shop. The exception reads No api found for destination ....

The Name Refers to a Proxy That Is Not a Service API

The name refers to a proxy such as proxy, sslProxy or stompProxy, which cannot be the target of internal routing. The exception reads Not a service proxy: ....

The Destination Is Not a Valid URI

A ${...} expression in the target url inserted spaces or other illegal characters, so the internal:// destination cannot be parsed.

An Unexpected Error in a Chain of Internal Targets

An unexpected exception while following a chain of internal targets is rare and usually indicates a bug in Membrane. An exception thrown by a plugin of the internal API is not reported here: the internal routing aborts without a response, which shows up as internal/http-handler/no-response-produced.

How to Fix It

Operator: make sure the name after internal:// matches the name of an internal API or another service API in the same configuration, including upper and lower case.
Operator: if the target url is built from an expression, check that the result is a valid URI.
Enable development mode, or in production look up the log key of the response in the gateway log. If the cause is none of the above, report the stack trace on GitHub Issues.

Hide Details in Production

By default, Membrane runs in development mode and adds details to error responses that help you find the problem. These details may reveal information about your setup. In production, turn them off:

configuration:
  production: true

configuration:
  production: true

Add the configuration document to your apis.yaml and separate it from the APIs with ---. The response then only contains a log key. Search the gateway log for this key to find the exception.