In flt_ot_sample_to_str() there were two occurrences of strncat() which
are used to copy N chars from the source and append a zero. For the sake
of definitely getting rid of this nasty function let's replace them by
memcpy() instead. It's worth noting that the length test there appeared
to be incorrect as it didn't make provisions for the trailing zero,
unless the size argument doesn't take it into account (seems unlikely).
Nothing was changed regarding this. If the code was good, it still is,
otherwise if it was bad it still is. At least this is more obvious now
than when using a function that needs n+1 chars to work.
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.
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.
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.
