source: gutenbach/debian/lib/README @ d9d50c7

debianmacno-cupsnodebathenaweb
Last change on this file since d9d50c7 was d9d50c7, checked in by Jessica B. Hamrick <jhamrick@…>, 14 years ago

Talk about how to let everyone lprm files.

Signed-off-by: Edward Z. Yang <edwardzyang@…>

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1sipbmp3
2    The SIPB MP3 Music Spooler
3
4We would love you forever if you took this README/INSTALL document and made
5a Debian package out of it.  That would be uber-awesome.  But otherwise, we're
6assuming that you just want to get sipbmp3 up and running on your own
7system.  Well, maybe we shouldn't assume that.
8
9
10What does sipbmp3 do?
11---------------------
12
13sipbmp3 is a music spooler.  As it turns out, streaming music is a hard
14problem, with lots of proprietary protocols, client and server software.
15All of these jiggety bits are kind of a pain to get working correctly,
16so, we built sipbmp3 on top of... a printer system.  It's very simple:
17you print an mp3 file to a special "printer", and it gets played on
18whatever speakers you're hooked up to.
19
20
21Prerequisites
22-------------
23
24You'll need a server hooked up to an audio system that you want to use, with
25Debathena installed on top of it.  Ubuntu Server Edition tends to work
26well.
27
28
29Installing sipbmp3
30------------------
31
32
331. Configuring your sound
34
35If you're installing sipbmp3 on a server environment, it's highly likely
36that you have a bare bones audio setup and everything is muted.  Make sure
37your sound works!  One common problem is that the daemon user (the user which
38will be actually playing the songs, or the user that your lpd, the print server,
39will be running under), isn't in the group audio, and thus can't play
40anything. If you're on Ubuntu Desktop, you'll probably have pulse-audio
41installed, in which case you should add lpd to the pulse-audio group
42as well, and make pulse-audio a single, system-wide instance. See
43this URL for detailed instructions:
44
45    http://www.pulseaudio.org/wiki/SystemWideInstance
46
47
482. Install some prerequisite software
49
50On a vanilla Ubuntu server install, sipbmp3 will also need the following
51packages to work properly:
52
53    * mplayer
54    * libimage-exiftool-perl
55
56mpg123 can also be useful for testing, but is not strictly necessary.
57
58
593. Setup sipbmp3
60
61The Git repository for sipbmp3 is located in:
62
63    /afs/sipb/project/sipbmp3/sipbmp3.git
64
65While sudo'ed as root, you should git clone this somewhere; zsr has
66it dumped in /usr/local/bin, while scourge puts it the more cordoned
67off /root/sipbmp3.
68
69
704. Configure sipbmp3
71
72sipbmp3 will send zephyrs during playback start and end.  Since you don't
73want to be spamming sipb-auto (which is the default zephyr class these
74are sent to), you should create a configuration file:
75
76    /etc/sipbmp3-filter-config.pl
77
78That looks like:
79
80    $zephyr_class = "my-auto-class"
81    $host = "hostname"
82
83XXX: Auto-detect hostname and invent a sane default zephyr class off of it.
84
85
865. Configure sipbmp3 init scripts
87
88sipbmp3 will attempt to drop some information into /var/run/sipbmp3, which
89needs to exist and you can't simply mkdir since /var/run on Ubuntu is
90a tempfs. Thus, add the following lines to a new file, /etc/init.d/sipbmp3:
91
92#!/bin/sh
93mkdir /var/run/sipbmp3
94touch /var/run/sipbmp3/status
95chmod 0777 /var/run/sipbmp3/status
96
97You should also run these commands yourself. :-)
98
99XXX: We need better permissions for status. Also, quentin wants to put this
100file in AFS.
101
102
1036. Configure lpd
104
105You'll need to setup a printcap file so that your machine will be actually
106running a printer! The magic lines are:
107
108    :if=|/path/to/sipbmp3-filter
109    :lp=/dev/null
110
111Which mean that we pipe the mp3 files through sipbmp3-filter (which does
112the actual playing), and then dump the rest of the output into /dev/null,
113since we don't actually care about it.
114
115A standard printcap entry looks like this:
116
117printername
118  :server
119  :cm=Human Readable Printer Name
120  :lp=/dev/null
121  :if=|/path/to/sipbmp3-filter
122  :sd=/var/spool/lpd/printername
123  :ml=0:mx=0:sh:sf
124  :auth_forward=kerberos5
125  :use_auth=kerberos5
126  :create_files
127
128printcap is located in /etc/printcap, but you can also edit the symlink
129in /etc/lprng/printcap.
130
131To check your modifications, and create the necessary files and folders,
132you should run:
133
134    checkpc -V -f
135
136(As root, of course). You might get a failure on a directory
137/var/spool/lpd/%P doesn't exist; simply mkdir it and run checkpc -V -f
138again.
139
140With recent versions of lprng, you will also need to make lpd less paranoid
141about accepting connections.  This usually means the following two changes:
142
143In /etc/lprng/lpd.perms:
144
145    REJECT NOT SERVER
146
147should be commented out, as:
148
149    #REJECT NOT SERVER
150
151And, in /etc/lprng/lpd.conf:
152
153    printcap_path=...
154
155add /etc/lprng/printcap to the beginning of the pathlist, so it looks like:
156
157    printcap_path=/etc/lprng/printcap:|/usr/lib/get_hesiod_pcap
158
159/etc/printcap will also work, assuming lprng doesn't do something funky
160in the future.
161
162You will also need to add this line:
163
164    lpd_listen_port=515
165
166By default, printers don't allow other users to remove other people's print
167jobs.  For an MP3 spooler, however, this may be a desirable trait, especially
168if someone trys to rickroll you.  You can let everyone lprm jobs by
169commenting out the line:
170
171    REJECT SERVICE=M
172
173XXX: On scourge, ACCEPT SERVICE=M SAMEHOST SAMEUSER doesn't seem to work
174properly, so removing the REJECT line is a must!
175
176XXXXXX: sipbmp3 accepts no responsibility for social faux pas that may
177be committed with this system.  It is consider good etiquette, however,
178to clear the status file if you're on zsr.
179
180
1817. Test, round one
182
183The first test you should do to make sure sipbmp3 is configured properly is
184to attempt to play an mp3 file locally, via lpr.  The command you should use
185is:
186
187    mit-lpr -Pprintername@localhost filename.mp3
188
189Note the "mit-" prefix; Debathena defaults to CUPS, which we have not set
190up yet.
191
192See below for troubleshooting tips.
193
194
1958. Test, round two
196
197The second test you should do is try playing an MP3 remotely. The appropriate
198command is:
199
200    mit-lpr -Pprintername@hostname filename.mp3
201
202(Once again, with "mit-").  See below for troubleshooting tips.
203
204
2059. Troubleshooting
206
207So, it didn't work.  How did it fail?
208
209----
210sending job 'ezyang@vivace+800' to asdfasdf@localhost
211 connecting to 'localhost', attempt 1
212 cannot open connection to localhost - No such file or directory
213----
214
215This means that lpd is not accepting connections properly.  Check to see
216if you configured lpd.perms and lpd.conf correctly.  Try rebooting lpd
217by pkill lpd && lpd.  Use nmap to check of port 515 is open, both on the
218local machine and on a remote machine.  Check if networking is working
219on the server.  Use netstat to see what programs are listening to port
220515, and from which hosts.  Check iptables.
221
222----
223lpr: The printer or class was not found.
224----
225
226You're using lpr, not mit-lpr.
227
228----
229(no output, but no sound)
230----
231
232It looks like you managed to send the file over.  To diagnose the problems
233further:
234
235    * Check the zephyr logs of the class sipbmp3 was configured to
236      send messages to:
237
238        - If you see a reasonably full and formatted message, that means
239          that either: 1. your volume is turned off, or 2. mplayer is
240          horribly broken (XXX: it probably isn't, but I don't know what
241          error message it gives in that case)
242
243          By the way, be sure to check both the *hardware* and the
244          *software* volume.
245
246        - If you see a blank zephyr, that means that sipbmp3-filter died
247          trying to get a handle to /var/run/sipbmp3/status and failing.
248          Check if you created the file correctly, and that daemon has
249          permissions to write to it. If you rebooted recently, check if
250          you have the appropriate init.d script setup.
251
252    * Otherwise, check /var/spool/lpd/printername/status.pr (most of all the
253      other files are useless, especially including log):
254
255        - If you see a Perl error, fix it. The most common cause is because
256          exiftools is not installed.
257
258    * Otherwise, double check the userland code in sipbmp3-filter. XXX: There
259      are some edge-cases that don't give nice error messages, for example
260      the failed write to /var/run/sipbmp3/status
261
262
26310. Deploying CUPS
264------------------
265
266The final step is to give your newfangled printer a cups.mit.edu record.
267In order to do this, you will need to ask IS&T for a Moira pcap entry
268request.  Send mail to hesreq@mit.edu, specifying that you are setting
269up a sipbmp3 clone, that you want a Moira pcap entry, the printer name
270and server name of your queue, and that you want hwtype=LOCAL. It wouldn't
271hurt to also tell them where your print queue is, and a contact list.
272
273Once you get the pcap entry, ping sipb-cups@mit.edu to add your machine
274to the public list.
275
276
277X. Setting up remctl commands
278-----------------------------
279
280It's useful to be able to control the volume. Remctl is the way to do
281this without asking people to ssh in, and then alsamix(er). XXX: These
282batch scripts and remctl files are not yet public.
283
284
285X. Deploying sipbmp3web
286------------------------
287
288sipbmp3 web provides a nice and user-friendly interface for some common
289tasks. XXX: It is currently not portable beyond zsr. Stay tuned!
290
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