The shellscript bootstrap for AWS Lambda Custom Runtime

lambda-custom-runtime-bootstrap.sh

#!/bin/sh
set -euo pipefail

function report_init_error() {
  curl -X POST "http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01/runtime/init/error" -d@- --header "Lambda-Runtime-Function-Error-Type: Unhandled"
}

function report_invocation_error() {
  curl -X POST "http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01/runtime/invocation/$REQUEST_ID/error" -d@- --header "Lambda-Runtime-Function-Error-Type: Unhandled"
}

source $LAMBDA_TASK_ROOT/"$(echo $_HANDLER | cut -d. -f0).sh" || { report_init_error <<<'{"errorMessage":"Failed to source the handler file."}'; false; }

while true
do
  headers="$(mktemp)"
  event=$(curl -sS -LD "$headers" -X GET "http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01/runtime/invocation/next")
  request_id=$(grep -Fi Lambda-Runtime-Aws-Request-Id "$headers" | tr -d '[:space:]' | cut -d: -f2)
  response=$($(echo "$_HANDLER" | cut -d. -f2) "$event") || { report_invocation_error <<<'{"errorMessage":"Invocation Error"}'; continue; }
  curl -X POST "http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01/runtime/invocation/$request_id/response" -d "$response"
done