HTTP

When Wombat runs it kicks off an HTTP server that provides a few generally useful endpoints and is also where configured components such as the http_server input and output can register their own endpoints if they don’t require their own host/port.

The configuration for this server lives under the http namespace, with the following default values:

Common
Advanced

# Common config fields, showing default values
http:
  address: 0.0.0.0:4195
  enabled: true
  root_path: /wombat
  debug_endpoints: false

# All config fields, showing default values
http:
  address: 0.0.0.0:4195
  enabled: true
  root_path: /wombat
  debug_endpoints: false
  cert_file: ""
  key_file: ""
  cors:
    enabled: false
    allowed_origins: [ ]
  basic_auth:
    enabled: false
    username: ""
    password_hash: ""
    algorithm: "sha256"
    salt: ""

The field enabled can be set to false in order to disable the server.

The field root_path specifies a general prefix for all endpoints, this can help isolate the service endpoints when using a reverse proxy with other shared services. All endpoints will still be registered at the root as well as behind the prefix, e.g. with a root_path set to /foo the endpoint /version will be accessible from both /version and /foo/version.

Enabling HTTPS

By default Wombat will serve traffic over HTTP. In order to enforce TLS and serve traffic exclusively over HTTPS you must provide a cert_file and key_file path in your config, which point to a file containing a certificate and a matching private key for the server respectively.

If the certificate is signed by a certificate authority, the cert_file should be the concatenation of the server’s certificate, any intermediates, and the CA’s certificate.

Enabling Basic Authentication

By default Wombat does not do any sort of authentication for the service-wide HTTP server. However, it’s possible to configure basic authentication with the basic_auth field. Passwords configured must be hashed according to the specified algorithm and base64 encoded, for some hashing algorithms you can do this using Wombat itself:

echo mynewpassword | wombat blobl 'root = content().hash("sha256").encode("base64")'

Endpoints

The following endpoints will be generally available when the HTTP server is enabled:

/version provides version info.
/ping can be used as a liveness probe as it always returns a 200.
/ready can be used as a readiness probe as it serves a 200 only when both the input and output are connected, otherwise a 503 is returned.
/metrics, /stats both provide metrics when the metrics type is either json_api or prometheus.
/endpoints provides a JSON object containing a list of available endpoints, including those registered by configured components.

CORS

In order to serve Cross-Origin Resource Sharing headers, which instruct browsers to allow CORS requests, set the subfield cors.enabled to true.

allowed_origins

A list of allowed origins to connect from. The literal value * can be specified as a wildcard. Note cors.enabled must be set to true for this list to take effect.

Debug Endpoints

The field debug_endpoints when set to true prompts Wombat to register a few extra endpoints that can be useful for debugging performance or behavioral problems:

/debug/config/json returns the loaded config as JSON.
/debug/config/yaml returns the loaded config as YAML.
/debug/pprof/block responds with a pprof-formatted block profile.
/debug/pprof/heap responds with a pprof-formatted heap profile.
/debug/pprof/mutex responds with a pprof-formatted mutex profile.
/debug/pprof/profile responds with a pprof-formatted cpu profile.
/debug/pprof/goroutine responds with a pprof-formatted goroutine profile.
/debug/pprof/symbol looks up the program counters listed in the request, responding with a table mapping program counters to function names.
/debug/pprof/trace responds with the execution trace in binary form. Tracing lasts for duration specified in seconds GET parameter, or for 1 second if not specified.
/debug/stack returns a snapshot of the current service stack trace.