fn-serverless/docs/function-file.md

Function files

Functions files are used to assist fn to help you when creating functions.

The files can be named as:

• func.yaml
• func.json

An example of a function file:

name: fnproject/hello
version: 0.0.1
type: sync
memory: 128
config:
  key: value
  key2: value2
  keyN: valueN
headers:
  content-type:
   - text/plain
build:
- make
- make test

name is the name and tag to which this function will be pushed to and the route updated to use it.

path (optional) allows you to overwrite the calculated route from the path position. You may use it to override the calculated route. If you plan to use fn test --remote="", this is mandatory.

version represents current version of the function. When deploying, it is appended to the image as a tag.

runtime represents programming language runtime, for examples, go, python3, java, etc. and the runtime docker when will use the existing Dockerfile if one exists.

build (optional) is an array of local shell calls which are used to help building the function.

type (optional) allows you to set the type of the route. sync, for functions whose response are sent back to the requester; or async, for functions that are started and return a task ID to customer while it executes in background. Default: sync.

memory (optional) allows you to set a maximum memory threshold for this function. If this function exceeds this limit during execution, it is stopped and error message is logged. Default: 128.

timeout (optional) is the maximum time a function will be allowed to run. Default is 30 seconds.

headers (optional) is a set of HTTP headers to be returned in the response of this function calls.

config (optional) is a set of configurations to be passed onto the route setup. These configuration options shall override application configuration during functions execution.

Hot functions

hot functions support also adds two extra options to this configuration file.

format (optional) is one of the streaming formats covered at function-format.md.

idle_timeout (optional) is the time in seconds a container will remain alive without receiving any new requests; hot functions will stay alive as long as they receive a request in this interval. Default: 30.

Testing functions

tests (optional) is an array of tests that can be used to valid functions both locally and remotely. It has the following structure

tests:
- name: envvar
  in: "inserted stdin"
  out: "expected stdout"
  err: "expected stderr"
  env:
    envvar: trololo

in (optional) is a string that is going to be sent to the file's declared function.

out (optional) is the expected output for this function test. It is present both in local and remote executions.

err (optional) similar to out, however it read from stderr. It is only available for local machine tests.

env (optional) is a map of environment variables that are injected during tests.