Servator

A service creator based on the state of the running system. The idea is to inspect a running system and create start scripts based on what is found running. Servator can also create applications for use with AppImage Mac OS X Applications and Windows applications (see below)

Normal release

It is so simple to create server scripts this way, example

$ erl -sname foo -s foo -config foo.config
> servator:make_release(foo).

Or if a version not in application env must be used

> servator:make_release(foo,"9.99").

> ...
> halt().

$ cd foo-1.0; ./install.sh

NOTE. If /etc/erlang/foo or /var/erlang/foo does not exist or are not owned by the current user. They must be created.

When creating a release all data is copied into a release structure that can be use standalone.

Soft release

$ erl -sname foo -s foo -config foo.config
> servator:make_soft_release(foo).
> ...
> halt().

$ cd foo-soft; ./install.sh

You may have to edit /etc/erlang/foo/foo.config to reflect the new home

The soft release create a release structure but will use symbolic links to refer to the libraries used.

More info about the release structure is found in RELEASE.md

Make a release when using rebar deps

To build a release for an applications that use rebar deps the following steps can be done:

$ git clone git@github.com/user/foo
$ cd foo
$ unset REBAR_DEPS_DIR		# we just want deps dir
$ unset ERL_LIBS			# ignore all other applications
$ rebar get-deps
$ rebar compile
$ erl -sname foo -pa ../foo/ebin/ -pa deps/*/ebin -config foo.config -s foo
> servator:make_release(foo, "1.01").

Commands

Starting the service is as simple as

/etc/erlang/<app>/<app>.run start

To stop then

/etc/erlang/<app>/<app>.run stop

Attach to the running node and get a shell

/etc/erlang/<app>/<app>.run attach

ctrl-C will only kill the client node.

To get current status

/etc/erlang/<app>/<app>.run status

will report 'down', 'up' or custom status if the function :status() is implemented and generate some status output ( safest is to use erlang:display to get some output )

Start in interactive mode

/etc/erlang/<app>/<app>.run interactive

To start a node in "normal" mode can be nice when debuging.

Linux init.d

$ sudo cp foo-1.0/etc/init.d/foo /etc/init.d/
$ sudo chmod +x /etc/init.d/foo
$ sudo update-rc.d foo defaults

Linux rc.local

To start an erlang service on most linux system when system starts add the following line to /etc/rc.local ( before any exit 0 )

# start <app> erlang service
/etc/erlang/<app>/<app>.run start

Mac OS X

On 10.10 ( and later ? )

sudo cp /etc/erlang/<app>/<rel>/org.erlang.<app>.plist /System/Library/LaunchDaemons/
sudo launchctl bootstrap system /System/Library/LaunchDaemons/org.erlang.<app>.plist
sudo launchctl kickstart system/org.erlang.<app>.plist
sudo launchctl enable system/org.erlang.<app>.plist

On 10.x before 10.10 ( still works in 10.10! )

sudo cp /etc/erlang/<app>/<rel>/org.erlang.<app>.plist /System/Library/LaunchDaemons/
sudo launchctl load -w /System/Library/LaunchDaemons/org.erlang.<app>.plist

Print current status (10.10 ?)

launchctl print system/org.erlang.xylan

10.11 (El Capitan)

In 10.11 it is no longer possible to install stuff under /System/Library/LaunchDaemons so instead /Library/LaunchDaemons is used

sudo cp /etc/erlang/<app>/<rel>/org.erlang.<app>.plist /Library/LaunchDaemons/
sudo launchctl load -w /Library/LaunchDaemons/org.erlang.<app>.plist

AppImage

erl -noshell -s foo -s servator make_appimage foo -s erlang halt

This will create a directory called foo.AppDir with a AppRun file in it. Now strip the erlang binaries and run appimage tool.

strip foo.AppDir/bin/beam.smp
strip foo.AppDir/bin/epmd
strip foo.AppDir/bin/erlc
strip foo.AppDir/bin/erl_child_setup
strip foo.AppDir/bin/erlexec
strip foo.AppDir/bin/escript
strip foo.AppDir/bin/heart
strip foo.AppDir/bin/inet_gethost
appimagetool -n foo.AppDir

This should produce an executable that can be run.

Max OS X Application

erl -noshell -s foo -s servator make_osxapp foo -s erlang halt

mkdir -p tmpdist
rm -rf tmpdist/Foo.app
mv Foo.app tmpdist/
(cd tmpdist/; ../../servator/priv/make_icns ../priv/foo.png)
rm -rf tmpdist/AppIcon.iconset
mv tmpdist/AppIcon.icns tmpdist/foo.app/Contents/Resources/
hdiutil create tmp.dmg -ov -volname "Foo" -fs HFS+ -srcfolder "./tmpdist/"
hdiutil convert -format UDZO -o Foo.dmg tmp.dmg
rm tmp.dmg

Windows application

erl -noshell -s foo -s servator make_win32app foo -s erlang halt