It is possible that some arguments within the configuration line are not
specified; that is, they are set to a blank string.
For example:
keyword '' arg_2
In that case the content of the args field will be like this:
args[0]: 'keyword'
args[1]: NULL pointer
args[2]: 'arg_2'
args[3 .. MAX_LINE_ARGS): NULL pointers
The previous way of calculating the number of arguments (as soon as a
null pointer is encountered) could not place an argument on an empty
string.
All of the above is essential for passing the OpenTracing context via
the HTTP headers (keyword 'inject'), where one of the arguments is the
context name prefix. This way we can set an empty prefix, which is very
useful if we get context from some other process that can't add a prefix
to that data; or we want to pass the context to some process that cannot
handle the prefix of that data.
In commit 9533a7038 new parameters have been added to the declaration
of function parse_logsrv().
This patch should be backported to all branches where the OpenTracing
filter is located.
This patch solves the problem reported in github issue #1204, where the
OpenTracing filter cannot communicate with the selected tracer if HAProxy
is run in daemon mode. The author of the reported issue uses Zipkin
tracer, while in this example Jaeger tracer is used (see gdb output below).
The problem is that the OpenTracing library is initialized before HAProxy
initialize the daemon mode. Establishing this mode kills the OpenTracing
thread, after which the correct operation of the OpenTracing filter is no
longer possible. Also, HAProxy crashes on deinitialization of the
OpenTracing library.
The initialization of the OpenTracing library has been moved from the
flt_ot_init() function (which is started before switching the HAProxy to
daemon mode) to the flt_ot_init_per_thread() function (which is run after
switching the HAProxy to daemon mode).
Gdb output of crashed HAProxy process:
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `../../../haproxy -f sa/haproxy.cfg'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x00007f8131fd5629 in pthread_join (threadid=140192831239936, thread_return=0x0) at pthread_join.c:45
45 pthread_join.c: No such file or directory.
(gdb) where
#0 0x00007f8131fd5629 in pthread_join (threadid=140192831239936, thread_return=0x0) at pthread_join.c:45
#1 0x00007f812f15abc7 in std:🧵:join() ()
from /tmp/haproxy-os-master/contrib/opentracing/test/libjaeger_opentracing_plugin-0.5.0.so
#2 0x00007f812f0fb6f7 in jaegertracing::reporters::RemoteReporter::close() ()
from /tmp/haproxy-os-master/contrib/opentracing/test/libjaeger_opentracing_plugin-0.5.0.so
#3 0x00007f812f0b7055 in jaegertracing::reporters::CompositeReporter::close() ()
from /tmp/haproxy-os-master/contrib/opentracing/test/libjaeger_opentracing_plugin-0.5.0.so
#4 0x00007f812f0b9136 in jaegertracing::Tracer::Close() ()
from /tmp/haproxy-os-master/contrib/opentracing/test/libjaeger_opentracing_plugin-0.5.0.so
#5 0x00007f81309def32 in ot_tracer_close (tracer=0x55fb48057390) at ../../src/tracer.cpp:91
#6 0x000055fb41785705 in ot_close (tracer=0x55fb48061168) at contrib/opentracing/src/opentracing.c:208
#7 0x000055fb4177fc64 in flt_ot_deinit (p=<optimized out>, fconf=<optimized out>) at contrib/opentracing/src/filter.c:215
#8 0x000055fb418bc038 in flt_deinit (proxy=proxy@entry=0x55fb4805ce50) at src/filters.c:360
#9 0x000055fb41893ed1 in free_proxy (p=0x55fb4805ce50) at src/proxy.c:315
#10 0x000055fb41888809 in deinit () at src/haproxy.c:2217
#11 0x000055fb41889078 in deinit_and_exit (status=0) at src/haproxy.c:2343
#12 0x000055fb4173d809 in main (argc=<optimized out>, argv=<optimized out>) at src/haproxy.c:3230
This patch should be backported to all branches where the OpenTracing
filter is located.
This one is the last optional module to build with haproxy, so let's move
it to addons/. It was renamed to "ot" as it was the only one whose USE_*
option did not match the directory name, now this is consistent.
Few changes were required, only the Makefile, and doc were adjusted, as
the directory was already self-contained and relocatable.
