If the OpenTracing filter is compiled using the 'OT_DEBUG=1' option, then
log messages are printed to stderr when the filter is running. In the log
one can then find (among other things) the order in which the function is
called and the value that the function returns (if it is not a void type).
Prior to applying this patch, no value returned by a function was logged.
Log output example:
[ 1] 0.038807 [OT]: flt_ot_init_per_thread(0x56365bd45ec0, 0x56365bd48210) {
[ 1] 0.038807 [OT]: ot_start(0x56365bd58920, 0x56365bd4e3a0, 0x7f561acba168:(nil)) {
[ 1] 0.038807 [OT]: } = 0
[ 1] 0.038807 [OT]: } = 0
This patch must be backported as far as 2.4.
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.
