HTTP trigger

In this document

• Overview

• Attributes

• Examples

Overview

The HTTP trigger is the only trigger created by default if not configured (by default, it has 1 worker). This trigger handles incoming HTTP requests at container port 8080, assigning workers to incoming requests. If a worker is not available, a 503 error is returned.

Attributes

Path	Type	Description
port	int	The NodePort (or equivalent) on which the function will serve HTTP requests. If empty, chooses a random port within the platform range. When running on k8s, this only has effect if serviceType of type nodePort is used
ingresses.(name).host	string	The host to which the ingress maps.
ingresses.(name).hostTemplate	string	The template used to generate an ingress host (use @nuclio.fromDefault for default template)
ingresses.(name).paths	list of strings	The paths that the ingress handles. Variables of the form {{.<NAME>}} can be specified using .Name, .Namespace, and .Version. For example, /{{.Namespace}}-{{.Name}}/{{.Version}} will result in a default ingress of /namespace-name/version.
readBufferSize	int	Per-connection buffer size for reading requests.
maxRequestBodySize	int	Maximum request body size. (default: 4MiB)
reduceMemoryUsage	bool	Reduces memory usage at the cost of higher CPU usage if set to true.
cors.enabled	bool	true to enable cross-origin resource sharing (CORS); (default: false).
cors.allowOrigins	list of strings	Indicates that the CORS response can be shared with requesting code from the specified origin (Access-Control-Allow-Origin response header); (default: ['*'] to allow sharing with any origin, for requests without credentials).
cors.allowMethods	list of strings	The allowed HTTP methods, which can be used when accessing the resource (Access-Control-Allow-Methods response header); (default: "HEAD, GET, POST, PUT, DELETE, OPTIONS").
cors.allowHeaders	list of strings	The allowed HTTP headers, which can be used when accessing the resource (Access-Control-Allow-Headers response header); (default: "Accept, Content-Length, Content-Type, X-nuclio-log-level").
cors.allowCredentials	bool	true to allow user credentials in the actual request (Access-Control-Allow-Credentials response header); (default: false).
cors.preflightMaxAgeSeconds	int	The number of seconds in which the results of a preflight request can be cached in a preflight result cache (Access-Control-Max-Age response header); (default: -1 to indicate no preflight results caching).
serviceType	string	(Kubernetes only) Kubernetes ServiceType, used by the Kubernetes service to expose the trigger. The default ServiceType is ClusterIP, which means that by default the trigger won’t be exposed outside of the cluster unless you configure a proper ingress or manually change the ServiceType to NodePort.
disablePortPublishing	bool	(Docker only) Allow disabling publishing the function container port on the host network
streamingFlushPeriod	string (duration)	When the response body is streamed, the trigger flushes the response buffer to the client at most every this period (e.g. "1s", "500ms"). This allows clients to receive data incrementally instead of only when the stream ends. Must be a positive duration. Default: "1s" (set during platform enrichment if omitted).

Examples

With 4 workers and a maximum body size of 1 KB -

triggers:
  myHttpTrigger:
    numWorkers: 4
    kind: "http"
    attributes:
      maxRequestBodySize: 1024

With a predefined port number -

triggers:
  myHttpTrigger:
    kind: "http"
    attributes:
      port: 32001

With ingresses -

triggers:
  myHttpTrigger:
    kind: "http"
    attributes:

      # See "Invoking Functions By Name With Kubernetes Ingresses" for more details
      # on configuring ingresses
      ingresses:
        templated-host:

          # e.g.: "my-func.some-namespace.nuclioio.com
          hostTemplate: "{{ .ResourceName }}.{{ Namespace }}.nuclioio.com"
          paths:
            - "/"

        http:
          host: "host.nuclio"
          paths:
            - "/first/path"
            - "/second/path"
        http2:
          paths:
            - "MyFunctions/{{.Name}}/{{.Version}}"

With CORS -

triggers:
  myCORSHttpTrigger:
    kind: "http"
    attributes:
      cors:
        enabled: true
        allowOrigins:
          - "foo.bar"
        allowHeaders:
          - "Accept"
          - "Content-Length"
          - "Content-Type"
          - "X-nuclio-log-level"
          - "MyCustomAllowedRequestHeader"
        allowMethods:
          - "GET"
          - "HEAD"
          - "POST"
          - "PATCH"
        allowCredentials: false
        preflightMaxAgeSeconds: 3600

With streaming flush period (for streamed response bodies) -

triggers:
  myHttpTrigger:
    kind: "http"
    attributes:
      streamingFlushPeriod: "1s"