make boot.sh process PID 1

README.md

@@ -53,6 +53,7 @@ Requires:
 - a semantic.works stack, like mu-project
 - 'Develop your first microservice'
 
+
 When developing inside an existing mu.semte.ch stack, it is easiest to set the development mode by setting the `NODE_ENV` environment variable to `development` and mount the sources directly.  This makes it easy to setup links to the database and the dispatcher. Livereload is enabled automatically when running in development mode.
 
 ```yml
@@ -216,6 +217,8 @@ The following SPARQL escape helpers are provided to construct safe SPARQL query
   - `sparqlEscapeDateTime(value) => string`
   - `sparqlEscapeBool(value) => string`: The given value is evaluated to a boolean value in javascript. E.g. the string value `'0'` evaluates to `false` in javascript.
   - `sparqlEscape(value, type) => string`: Function to escape a value in SPARQL according to the given type. Type must be one of `'string'`, `'uri'`, `'int'`, `'float'`, `'date'`, `'dateTime'`, `'bool'`.
+  - `setExitHandler`: *experimental* Sets a function to be ran on exit.  The default implementation executes `process.exit` which allows for fast exiting of the service and therefore also fast restarts.
+
 
 ### Error handling
 The template offers [an error handler](https://expressjs.com/en/guide/error-handling.html) to send error responses in a JSON:API compliant way. The handler can be imported from `'mu'` and need to be loaded at the end.

helpers/mu/index.js

@@ -1,4 +1,4 @@
-import { app, errorHandler } from './server.js';
+import { app, errorHandler, setExitHandler } from './server.js';
 import sparql from './sparql.js';
 import { v1 as uuidV1 } from 'uuid';
 
@@ -53,7 +53,8 @@ export {
   sparqlEscapeDateTime,
   sparqlEscapeBool,
   uuid,
-  errorHandler
+  errorHandler,
+  setExitHandler
 };
 
 export default mu;

helpers/mu/server.js

@@ -36,14 +36,38 @@ const errorHandler = function(err, req, res, next) {
   });
 };
 
+
 // start server
-app.listen( port, hostname, function() {
+const server = app.listen( port, hostname, function() {
   console.log(`Starting server on ${hostname}:${port} in ${app.get('env')} mode`);
 });
 
+// faster stopping
+let exitHandler = function(server) {
+  console.debug("Preparing to shut down");
+  server.close( () => {
+    console.debug("Shut down complete");
+  });
+};
+
+/**
+ * Sets a new handler for shutting down the server.
+ *
+ * @arg functor Function taking one argument (the result of app.listen
+ * when starting the server) which should gracefully stop the server.
+ */
+function setExitHandler( functor ) {
+  this.exitHandler = functor;
+}
+
+process.on('SIGTERM', () => exitHandler(server) );
+process.on('SIGINT', () => exitHandler(server) );
+
+
 export default app;
 
 export {
   app,
-  errorHandler
+  errorHandler,
+  setExitHandler
 }