If a hook function neither calls the callback nor returns a
(non-undefined) value then there's no way for the hook system to know
if/when the hook function has finished.
* `src/node/server.js` can now be run as a script (for normal
operation) or imported as a module (for tests).
* Move shutdown actions to `src/node/server.js` to be close to the
startup actions.
* Put startup and shutdown in functions so that tests can call them.
* Use `await` instead of callbacks.
* Block until the HTTP server is listening to avoid races during
test startup.
* Add a new `shutdown` hook.
* Use the `shutdown` hook to:
* close the HTTP server
* call `end()` on the stats collection to cancel its timers
* call `terminate()` on the Threads.Pool to stop the workers
* Exit with exit code 0 (instead of 1) on SIGTERM.
* Export the HTTP server so that tests can get the HTTP server's
port via `server.address().port` when `settings.port` is 0.
This change is only cosmetic. Its aim is do make it easier to understand the
async changes that are going to be merged later on. It was extracted from the
original work from Ray Bellis.
To verify that nothing has changed, you can run the following command on each
file touched by this commit:
npm install uglify-es
diff --unified <(uglify-js --beautify bracketize <BEFORE.js>) <(uglify-js --beautify bracketize <AFTER.js>)
This is a complete script that does the same automatically (works from a
mercurial clone):
```bash
#!/usr/bin/env bash
set -eu
REVISION=<THIS_REVISION>
PARENT_REV=$(hg identify --rev "${REVISION}" --template '{p1rev}')
FILE_LIST=$(hg status --no-status --change ${REVISION})
UGLIFYJS="node_modules/uglify-es/bin/uglifyjs"
for FILE_NAME in ${FILE_LIST[@]}; do
echo "Checking ${FILE_NAME}"
diff --unified \
<("${UGLIFYJS}" --beautify bracketize <(hg cat --rev "${PARENT_REV}" "${FILE_NAME}")) \
<("${UGLIFYJS}" --beautify bracketize <(hg cat --rev "${REVISION}" "${FILE_NAME}"))
done
```
Until Etherpad 1.7.5, process.on('SIGTERM') and process.on('SIGINT') were not
hooked up under Windows, because old nodejs versions did not support them.
This excluded the possibility of doing a graceful shutdown of the database
connection under that platform.
According to nodejs 6.x documentation, it is now safe to do so. This allows to
gracefully close the DB connection when hitting CTRL+C under Windows, for
example.
Source: https://nodejs.org/docs/latest-v6.x/api/process.html#process_signal_events
- SIGTERM is not supported on Windows, it can be listened on.
- SIGINT from the terminal is supported on all platforms, and can usually be
generated with <Ctrl>+C (though this may be configurable). It is not
generated when terminal raw mode is enabled.
Shut down database connection and exit the node process
when SIGTERM is encountered. This is especially important
when nodejs is run as PID1, e.g. in a docker container.
Shutting down connections to clients (browsers) is beyond
this patche's scope.
Resolves#3265
