SIP-based Announcement / PA / Paging / Public Address Server system
Project description
SIP-based Announcement / PA / Paging / Public Address Server system.
Main component of this project is a script to run PJSUA SIP client connected to a JACK sound server routing audio to whatever sound cards and speaker sets.
It picks up calls, plays klaxon on speakers, followed by the announcement made in that call. Music plays in-between announcements.
Script controls PJSUA and JACK to make them work to that effect.
Usage
After installation (see below), the script should be configured, providing it with at least the SIP account data for the general usage.
Configuration file (ini format) locations:
paging.conf
/etc/paging.conf
callpipe.conf
/etc/callpipe.conf
Paths specified on the command line.
All files will be looked up and parsed in that order, values in next ones overriding corresponding ones in the previous and defaults.
See output of paging --help for info on how to specify additional configuration, more up-to-date list of default paths, as well as general information for all the other options available.
Provided paging.example.conf file has all the available configuration options and their descriptions.
To see default configuration options, use paging --dump-conf-defaults, and run paging --dump-conf ... to see the actual options being picked-up and used at any time.
There are two general (supported) ways to start and run the script:
In the foreground (non-forking).
As a systemd service.
Both are described in more detail below.
Start/run in the foreground
Aka simple non-forking start.
Just run the thing as:
% paging
Can be used directly from terminal, or with any init system or daemon manager, including systemd, upstart, openrc, runit, daemontools, debian’s “start-stop-daemon”, simple bash scripts, etc.
For systemd in particular, see the “Running as a systemd service” section below.
Running from terminal to understand what’s going on, these options might be also useful:
% paging --debug % paging --debug --pjsua-log-level 10 % paging --dump-conf
See also “Installation” and “Audio configuration” sections below.
Running as a systemd service
This method should be preferred, as it correctly notifies init when service is actually ready (i.e. pjsua inputs/outputs initialized), so that others can be scheduled around that, and primes watchdog timer, detecting if/when app might hang due to some bug.
Provided paging.service file (in the repository, just an ini file) should be installed to /etc/systemd/system, and assumes following things:
PagingServer app should be run as a “paging” user, which exists on the system (e.g. in /etc/passwd).
“paging.py” script, its “entry point” or symlink to it is installed at /usr/local/bin/paging.
Configuration file can be read from one of default paths (see above for a list of these).
Optional python-systemd module dependency is installed.
With all these correct, service can then be used like this:
Start/stop/restart service:
% systemctl start paging % systemctl stop paging % systemctl restart paging
Enable service to start on OS boot: systemctl enable paging
See if service is running, show last log entries: systemctl status paging
Show all logging for service since last OS boot: journalctl -ab -u paging
Brutally kill service if it hangs on stop/restart: systemctl kill -s KILL paging (will be done after ~60s by systemd automatically).
See systemctl(1) manpage for more info on such commands.
If either app itself is installed to another location (not /usr/local/bin/paging) or extra command-line parameters for it are required, ExecStart= line can be altered either in installed systemd unit file directly, or via systemctl edit paging.
systemctl daemon-reload should be run for any modifications to /etc/systemd/system/paging.service to take effect.
Similarly, User=paging line can be altered or overidden to change system uid to use for the app.
If python-systemd module is unavailable, following lines should be dropped from the paging.service:
Type=notify WatchdogSec=...
And --systemd option removed from ExecStart= line, so that app would be started as a simple non-forking process, which will then be treated correctly by systemd without two options above.
Installation
This is a regular package for Python 2.7 (not 3.X), but with some extra run-time requirements (see below), which can’t be installed from PyPI.
Package itself can be installed at any time using pip, e.g. via pip install PagingServer (this will try to install stuff to /usr!!!).
Unless you know python packaging though, please look at pip2014.com, python packaging tutorial, documentation below for easy installation (from packages/repo) on specific systems, or a more detailed step-by-step instructions for both python package and other requirements in “README.install.rst” file.
Requirements
Python 2.7 (NOT 3.X).
PJSUA (PJSIP User Agent) and its python bindings.
Can be packaged as “pjsip”, “pjsua” or “pjproject” in linux distros.
Python bindings (from the same tarball) can also be packaged separately as “python-pjproject” or something like that.
If either of those isn’t available, be sure to build and install pjsua AND its python bindings manually from the same sources, and NOT e.g. install pjsua from package and then build bindings separately.
JACK - both JACK1 (C) and JACK2 (C++) forks should work.
Only tested with JACK1 fork, but as both have same ABI and only interacted with via libjack, there should be no difference wrt which one is actually running.
(optional) ffmpeg binary - if audio samples are not wav files (will be converted on every startup, if needed).
(optional) python-systemd - only if --systemd option is used (e.g. with shipped .service file).
Developed and shipped separately from main systemd package since v223 (2015-07-29), likely comes installed with systemd prior to that.
Would probably make sense to install that module from OS package, which should be available if systemd is used there as init by default.
(optional) raven python module - for reporting any errors via sentry.
Debian Jessie
TODO: packages/repo
Other systems
TODO: build script
See also “README.install.rst” file for more information on the manual installation process.
Audio configuration
Overview of the software stack related to audio flow:
PJSUA picks-up the calls, decoding audio streams from SIP connections.
PJSUA outputs call audio to via PortAudio.
PortAudio can use multiple backends on linux systems, including:
ALSA libs (and straight down to linux kernel)
OSS (/dev/dsp*, only supported through emulation layer in modern kernels)
JACK sound server
PulseAudio sound server (with a somewhat unstable patch, see comment on #3 for details)
In this particular implementation, JACK backend is used, as it is necessary to later multiplex PJSUA output to multiple destinations and mix-in sounds from other sources there.
So PortAudio sends sound stream to JACK.
JACK serves as a “hub”, receiving streams from music players (mpd instances), klaxon sounds, calls picked-up by PJSUA.
JACK mixes these streams together, muting and connecting/disconnecting some as necessary, controlled by the server script (“paging”).
End result is N stream(s) corresponding to (N) configured hardware output(s).
JACK outputs resulting sound stream(s) through ALSA libs (and linux from there) to the sound hardware.
Hence audio configuration can be roughly divided into these sections (at the moment):
Sound output settings for PJSUA.
Related configuration options:
pjsua-device
pjsua-conf-port
As PortAudio (used by pjsua) can use one (and only one) of multiple backends at a time, and each of these backend can have multiple “ports” in turn, pjsua-device should be configured to use JACK backend “device”.
To see all devices that PJSUA and PortAudio detects, run:
% paging --dump-pjsua-devices Detected sound devices: [0] HDA ATI SB: ID 440 Analog (hw:0,0) [1] HDA ATI SB: ID 440 Digital (hw:0,3) [2] HDA ATI HDMI: 0 (hw:1,3) [3] sysdefault [4] front [5] surround21 [6] surround40 ... [13] dmix [14] default [15] system [16] PulseAudio JACK Source
(output is truncated, as it also includes misc info for each of these devices/ports that PortAudio/PJSUA provides)
This should print a potentially-long list of “playback devices” (PJSUA terminology) that can be used for output there, as shown above.
JACK default output (as created by e.g. -d dummy option to jackd) in the example list above is called “system” - same as in JACK, and should be matched by default.
If any other JACK-input/PortAudio-output should be used, it can be specified either as numeric id (number in square brackets on the left) or regexp (python style) to match against name in the list.
To avoid having any confusing non-JACK ports there, PortAudio can be compiled with only JACK as a backend.
pjsua-conf-port option can be used to match one of the “conference ports” from paging --dump-pjsua-conf-ports command output in the same fashion, if there will ever be more than one (due to more complex pjsua configuration, for example), otherwise it’ll work fine with empty default.
JACK daemon startup and control client connection configuration.
Related configuration options:
jack-autostart
jack-server-name
jack-client-name
All of these are common JACK client settings, described in jackd(1), jackstart(1) manpages, libjack or jack-client module documentation.
With exception for self-explanatory jack-autostart (enabled by default), these options should be irrelevant, unless this script is used with multiple JACK instances or clients.
Configuration for any non-call inputs (music, klaxons, etc) for JACK.
Related configuration options:
klaxon
jack-music-client-name
jack-music-links
“klaxon” can be a path to any file that has sound in it (that ffmpeg would understand), and will be played before each announcement call on all “jack-output-ports” (see below), and before that call gets answered.
“jack-music-client-name” should be a regexp to match outputs of music clients, that should play stuff in-between announcements, and “jack-music-links” allows to control which set(s) of speakers they’ll be connected to.
For example, if mpd.conf has something like this:
audio_output { type "jack" name "jack" client_name "mpd.paging:test" }Then configuration like this (these are actually defaults):
jack-music-client-name = ^mpd\.paging:(.*)$ jack-music-links = left---left right---right
Will connect output from that player to all speakers matched by “jack-output-ports” (all available to JACK by default).
Script can be run with --dump-jack-ports option to show all JACK ports that are currently available - all connected players, speakers, cards and such.
See more detailed description of these options and how they’re interpreted in paging.example.conf.
List of hardware outputs (ALSA PCMs) to use as JACK final outputs/sinks.
Related configuration options:
jack-output-ports
Same as with PJSUA outputs/ports above, jack-output-ports can be enumerated via paging --dump-jack-ports command, and filtered by direct id or name regexp, if necessary.
Default is to route PJSUA call to all outputs available in JACK.
All settings mentioned here are located in the [audio] section of the configuration file.
See paging.example.conf for more detailed descriptons.
Misc tips and tricks
Collection of various things related to this project.
Pre-convert klaxon sound(s) to wav from any format
Can be done via ffmpeg with:
ffmpeg -y -v 0 -i sample.mp3 -f wav sample.wav
Where it doesn’t actually matter which format source “sample.mp3” is in - can be mp3, ogg, aac, mpc, mp4 or whatever else ffmpeg supports.
Might help to avoid startup delays due to conversion of these on each run.
If pjsua will be complaining about sample-rate difference between wav file and output, e.g. -ar 44100 option can be used (after -f wav) to have any sampling rate for the output file.
Running JACK on a system where PulseAudio is the main sound server
First of all, jackd has to be started manually there, and strictly before pulseaudio server.
/etc/pulse/default.pa should have something like this at the end (after default sink - probably alsa - init!):
load-module module-jack-source source_name=jack_in load-module module-loopback source=jack_in
That will create an output from JACK to PulseAudio and from there to whatever actually makes sound on the particular system, provided that the loopback stream and source in question are not muted and have some non-zero volume set in pulse.
“module-jack-source” has options for picking which jackd to connect to, if isn’t not “default”, “module-loopback” after it creates a stream from that jack source to a default sink (which is probably an ALSA sink).
On the JACK side, “PulseAudio JACK Source” port (sink) gets created, and anything connected there will make its way to pulseaudio.
Running mpd player connected to JACK
Music Player Daemon (mpd) is a nice player, well-suited for purposes of hands-off playing music all day long in-between any kind of announcements.
It also has a vast number of clients, including evertyhing from IR remote listeners (via lirc), bluetooth phones, car stereos, to more conventional desktop apps and WebUIs.
Example configuration for mpd with JACK output and “client_name” recognized by default PagingServer configuration and suitable for playing pretty much anything:
log_file "/dev/stdout"
music_directory "/mnt/music"
# password "super-secret-admin-password@read,add,control,admin"
# password "password-for-teh-peeple@read,add,control"
input {
plugin "curl"
}
audio_output {
type "jack"
name "jack"
client_name "mpd.paging:test"
autostart "no"
}
Note that “password” lines are commented-out, which will allow any client to connect without any kind of authorization, so it might be a good idea to change these if control port is to be exposed to any kind of non-localhost network.
Benchmark script (callram.py)
Description below is from old README.md file pretty much verbatim.
We’ve tested this script with thousands of calls, it is fairly reliable and light on resources. Total CPU use on a Pentium 4 @ 2.8ghz hovered around 0.5% with 4MB ram usage. identical figures were observed on a Celeron D @ 2.53Ghz, you could probably get away with whatever your operating system requires to run in terms of hardware.
To benchmark, you’ll need to set up callram.py.
Setting up callram.py
This setup assumes you have PJSUA installed, if not, go back to Installation earlier in this readme and install it.
Put the files in the right places:
sudo cp callram.py /opt/bin/callram.py sudo cp callram.example.conf /etc/callram.conf
Add your SIP account:
sudo nano /etc/callram.conf
Change the top 3 values to your SIP server, username (usually ext. number) and password.
Then fill in both SIP URI: fields (uri= and to=) with the SIP URI of the client you’d like to test.
SIP URIs are usually formatted as sip:<extension#>@<exampledomain.com> in most cases.
The Domain may sometimes be an IPv4 or IPv6 address depending on your setup.
Run:
/usr/bin/python /opt/bin/callram.py
Sending error reports to Sentry
Sentry is a “modern error logging and aggregation platform”.
Python raven module has to be installed in order for this to work.
If you followed manual installation instructions from README.install.rst, then it should be installed into the same virtualenv as the PagingServer itself, i.e. from a root shell run:
% su - paging % . PagingServer/bin/activate % pip install raven % exit
Otherwise that module can be installed from an OS package, if available (recommended), or via standard python packaging tools (see python packaging tutorial).
Then uncomment and/or set “sentry_dsn” option under the [server] section of the configuration file.
It can also be set via --sentry-dsn command-line option, e.g. in systemd unit distributed with the package, to apply on all setups where package is deployed.
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