Daemon - Revision history

Unhammer: /* Flushing examples in bash */

2022-06-03T11:56:58Z

Flushing examples in bash

2021-03-11T14:55:18Z

vislcg3 CG format

2021-03-11T14:54:50Z

vislcg3 CG format

2021-03-11T14:54:06Z

Flushing examples in bash

2016-11-16T12:24:55Z

don't add trailing newline

2016-11-16T12:03:38Z

Flushing examples in bash

2016-11-04T10:19:22Z

vislcg3 CG format

2016-11-04T10:19:04Z

Flushing examples in bash

2014-01-20T08:28:32Z

Flushing examples in bash

2014-01-16T10:31:01Z

@@ Line 61: / Line 61: @@
 From the apertium-nno-nob directory, try running
-<pre>./server lt-proc -zwe nno-nob.automorf.bin</pre>
+<pre>./daemon lt-proc -zwe nno-nob.automorf.bin</pre>
 in one terminal, then in another terminal, in the same directory, do
 <pre>echo Det der med krikar og krokar|apertium-destxt |./client</pre>
@@ Line 81: / Line 81: @@
 </pre>
 and run the server like
-<pre>./server vislcg3 -g nob-nno.rlx.bin</pre>
+<pre>./daemon vislcg3 -g nob-nno.rlx.bin</pre>
 ==== Chaining several daemons ====

@@ Line 67: / Line 67: @@
 ==== vislcg3 CG format ====
-If you want vislcg3 to flush, you have to insert &lt;STREAMCMD:FLUSH&gt; instead of NUL in the stream. The client then becomes something like
+If you want vislcg3 (not cg-proc) to flush, you have to insert &lt;STREAMCMD:FLUSH&gt; instead of NUL in the stream. The client then becomes something like
 <pre>
@@ Line 81: / Line 81: @@
 </pre>
 and run the server like
-<pre>./server cg-proc -z nob-nno.rlx.bin</pre>
+<pre>./server vislcg3 -g nob-nno.rlx.bin</pre>
 ==== Chaining several daemons ====

@@ Line 80: / Line 80: @@
 awk '{print} /^<STREAMCMD:FLUSH>$/{exit}' <&4
 </pre>
-while the server is essentially the same.
+and run the server like
+<pre>./server cg-proc -z nob-nno.rlx.bin</pre>
 ==== Chaining several daemons ====

@@ Line 37: / Line 37: @@
 rm -f to from
 mkfifo to from
+# Expects the command line to run as arguments:
-lt-proc -zwe nn-nb.automorf-no-cp.bin  <to  >from  &  pid=$!
+"$@"  <to  >from  &  pid=$!
 # Open some file descriptors so the fifo's are open for the duration of the lt-proc process:
 exec 3>to
@@ Line 59: / Line 60: @@
 </pre>
-From the apertium-nn-nb directory, try running <tt>./server</tt> in one terminal, then in another terminal, in the same directory, do <pre>echo Det der med krikar og krokar|apertium-destxt |./client</pre>
+From the apertium-nno-nob directory, try running
+<pre>./server lt-proc -zwe nno-nob.automorf.bin</pre>
-(or run <tt>./server &</tt> and then the above command in the same terminal)
+in one terminal, then in another terminal, in the same directory, do
+<pre>echo Det der med krikar og krokar|apertium-destxt |./client</pre>
 ==== vislcg3 CG format ====

@@ Line 54: / Line 54: @@
 cat >&3
 printf '\0' >&3
-awk 'BEGIN{RS="\0"}{print;exit}' <&4
+awk 'BEGIN{RS="\0"}{printf "%s", $0;exit}' <&4
 # With GNU head (e.g. on Ubuntu), you can just use -z for 0-terminated "lines":
 #head -1 -z <&4

@@ Line 53: / Line 53: @@
 cat >&3
-echo -e '\0' >&3
+printf '\0' >&3
 while read -rd '' <&4; do echo -n "$REPLY"; break; done
 </pre>
@@ Line 59: / Line 59: @@
 From the apertium-nn-nb directory, try running <tt>./server</tt> in one terminal, then in another terminal, in the same directory, do <pre>echo Det der med krikar og krokar|apertium-destxt |./client</pre>
 (or run <tt>./server &</tt> and then the above command in the same terminal)
+==== vislcg3 CG format ====
+If you want vislcg3 to flush, you have to insert &ltSTREAMCMD:FLUSH&gt; instead of NUL in the stream. The client then becomes something like
+<pre>
+#!/bin/bash
+# file: vislcg3-client
+exec 3>to
+exec 4<from
+cat >&3
+echo '<STREAMCMD:FLUSH>' >&3
+awk '{print} /^<STREAMCMD:FLUSH>$/{exit}' <&4
+</pre>
+while the server is essentially the same.
 ==== Chaining several daemons ====

@@ Line 22: / Line 22: @@
 === Flushing examples in bash ===
-Here's a small set of scripts showing how to do NUL flushing in bash, using apertium-nn-nb as an example.
+For a minimal example of NUL flushing from the command line, see [[NUL flushing]].
+Here's a small set of scripts showing how to do NUL flushing in bash for use in e.g. a web server. We use apertium-nn-nb as an example, but it should work with any language pair; the modules lt-proc/cg-proc/apertium-{tagger,pretransfer,transfer,interchunk,postchunk}/lrx-proc all support NUL flushing.
 The trick here is to use named pipes, also known as fifo's. Typically a process writes output to the special file descriptors "standard out" and reads input from "standard in". When you do <tt>echo foo &gt; file.txt</tt> you redirect standard out to file.txt instead of standard out. But you can also redirect it to a named pipe, which is a sort of virtual file, similar to "standard out". Then you can redirect that named pipe to be the ''input'' to another process. (In fact, this is what happens under the hood when you type <tt>grep foo file.txt | sed 's/o/l/'</tt>, except here you get an unnamed pipe between grep and sed.)

← Older revision		Revision as of 10:31, 16 January 2014
Line 1:		Line 1:
	Keeping processes open and using them as '''daemons''' lets you avoid some startup time if you do a lot of short translation requests. This is useful if you want to use Apertium on a web server, where starting up all programs in the pipeline for every single request would lead to a lot of lag.		Keeping processes open and using them as '''daemons''' (alternatively, using programs as libraries in separate threads) lets you avoid some startup time if you do a lot of short translation requests. This is useful if you want to use Apertium on a web server, where starting up all programs in the pipeline for every single request would lead to a lot of lag.

	If you want a pre-packaged daemon solution, see [[Apertium services]]. This page gives details on how to use some of the same techniques yourself.		If you want a pre-packaged daemon solution, see [[Apertium services]]. This page gives details on how to use some of the same techniques yourself.