/
lambda.js
100 lines (90 loc) · 2.54 KB
/
lambda.js
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const childProcess = require('child_process');
const os = require('os');
const split = require('./node_vendor/split');
const DEFAULT_PROGRAM = 'bin/' + os.platform() + '64';
const MAX_FAILS = 4;
var currentRequestId = null;
var dones = {};
var failCount = 0;
var go = null;
var spawn = defaultSpawn;
function exit(code) {
if (go) {
go.kill();
}
process.exit(code);
}
function callDone(requestId, err, data) {
var done = requestId ? dones[requestId] : null;
if (!done) {
if (err) {
console.error(err.message);
}
console.error(dones);
console.error('cannot call done for request ID ' + requestId);
exit(1);
}
done(err, data);
delete dones[requestId];
}
function defaultSpawn() {
if (process.env.NODE_ENV === 'development') {
return childProcess.spawn('go', ['run', 'main.go'], {stdio: ['pipe', 'pipe', process.stderr]});
}
return childProcess.spawn(DEFAULT_PROGRAM, {stdio: ['pipe', 'pipe', process.stderr]});
}
function handleFail() {
if (++failCount > MAX_FAILS) {
exit(1);
}
spawnSubProcess();
}
function spawnSubProcess() {
go = spawn();
go.on('error', function (err) {
process.stderr.write('Go process errored: ' + JSON.stringify(err) + '\n');
handleFail();
callDone(currentRequestId, err);
});
go.on('exit', function (code) {
process.stderr.write('Go process exited prematurely with code: ' + code + '\n');
handleFail();
callDone(currentRequestId, new Error('Exited with code ' + code));
});
go.stdin.on('error', function (err) {
process.stderr.write('Go process stdin write error: ' + JSON.stringify(err) + '\n');
handleFail();
callDone(currentRequestId, err);
});
go.stdout.pipe(split()).on('data', function (line) {
failCount = 0;
var res = JSON.parse(line.toString('utf-8'));
if (res.error) {
callDone(res.id, new Error(res.error));
} else {
callDone(res.id, null, res.reply);
}
});
}
exports.init = function (spawnOverride) {
if (go) {
console.error('go-lambda already initialized');
exit(1);
} else if (typeof spawnOverride != 'undefined') {
if (typeof spawnOverride != 'function') {
console.error('spawnOverride must be function');
exit(1);
}
spawn = spawnOverride;
}
spawnSubProcess();
};
exports.handle = function (event, context) {
if (!go) {
console.error('go-lambda not initialized');
exit(1);
}
currentRequestId = context.awsRequestId;
dones[currentRequestId] = context.done.bind(context);
go.stdin.write(JSON.stringify({context: context, event: event}) + '\n');
};