smacker
Don't smack your developers when a process misbehaves. It's hard to know everything a Node.js process does.
Did you know?
- Packages you use can emit warnings on
process.emitWarning
for deprecation notices and unexpected usage, without affecting functionality. - Both
SIGINT
and SIGTERM
will by default try to kill your process, without notifying you. This can be confusing when running your Node.js process in foreign environments. - Node.js v10.12.0 introduced a new event called
multipleResolves
- which they recommend should terminate your process, even though it doesn't default to that behaviour.
smacker gracefully handles all these nitty gritties, and fits perfectly into a microservice environment.
Usage
const smacker = require('smacker');
const Service = require('lib/Service');
const service = new Service();
smacker.start(service);
Check out the demo in test/demo.js
.
smacker.start(service, {[config][, log] })
service
<Object>
must have a start
and stop
function, both returning a Promise
config
<Object>
configuration object, contains config for smacker - see belowlog
<Object>
logging object for smacker to use, defaults to console
. Should have info
, warn
, and fatal
.
smacker will call service.start
on smacker.start
, and expect the resulting promise to resolve. It installs handlers for SIGINT
, SIGTERM
and SIGUSR2
and calls service.stop
when it receives one of these signals.
Unhandled exceptions and unhandled promise rejections are caught, logged, and your process will be terminated with exit code 1.
It also ensures warnings from process.emitWarning
are logged through your logging object.
config
logJson
<Boolean>
determines whether smacker will try to serialize the object before giving it to your logging object. Can be set via the LOGJSON
environment variable. Defaults to false
.terminateOnMultipleResolves
<Boolean>
smacker can terminate on the multipleResolves
event. This is not always desireable. It defaults to true
, since that is recommended behaviour.gracefulShutdownTimeout
<Number>
smacker will terminate after configured milliseconds (triggered by signals or natually), with exit code 1, if configured. Defaults to undefined
.gracefulStartupTimeout
<Number>
smacker will terminate after configured milliseconds, with exit code 1, if configured and the start
-function isn't resolved. Defaults to undefined
.signalHandlers[signal]
custom signal handlers can be installed after the start
-function has been resolved. This will overwrite the native behaviour of the signals. Valid signals are SIGHUP
, SIGPIPE
, SIGUSR2
.
Planned features
- detecting if
service.stop
actually leaves the event loop empty