lambda shim

lambda.py

import subprocess
import json

proc = subprocess.Popen(['./main'],
  stdin=subprocess.PIPE,
  stdout=subprocess.PIPE,
  universal_newlines=True,
  bufsize=1)

def id_generator():
    n = 0
    while True:
        yield n
        n += 1

ids = id_generator()

def handle(event, context):
  # write event
  # TODO: context is not JSON serializable
  proc.stdin.write(
    json.dumps(
        {
    'id': ids.send(None),
    'event': event,
    'context': {}
}
    )
    )

  # read event
  line = proc.stdout.readline()
  event = json.loads(line)

  # respond
  # TODO: raise exception on error
  return event['value']


event_value = handle(event="my_event", context={"hello": "world"})
print("event_value::", event_value)

main.go

package main

import (
	"encoding/json"
	"fmt"
)

func main() {
	type Err struct {
		Error string
	}
	errr := Err{Error: "unable to json Marshal"}
	jsonErr, _ := json.Marshal(errr)

	type Out struct {
		Name  string
		Age   int32
		Value string `json:"value,omitempty"`
	}
	out := Out{Name: "Komu", Age: 30, Value: "The real thing we want."}
	b, err := json.Marshal(out)
	if err != nil {
		fmt.Print(string(jsonErr))
	}
	fmt.Print(string(b))
}