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.
Due to a recent change in the handling of haproxy variables, their use for
OpenTracing context transfer has been excluded from the compilation process.
The use of variables can be re-enabled if the newly defined variable
OT_USE_VARS is set to 1 when calling the 'make' utility. However,
this should not be used for now as the compilation will end in error.
This change prevents the use of haproxy variables to convey the OpenTracing
context. This means that the 'use-vars' parameter cannot be used in the
OpenTracing filter configuration for 'inject' and 'extract' operations.
An example configuration that uses this feature is in the test/ctx
directory, while the script to run that test is test/run-ctx.sh.
Then, the 'sess.ot.uuid' variable is no longer set when initializing the
OpenTracing session. This means that this variable can still be used in
the OpenTracing configuration, but its contents will be empty.
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.
