RepoMirrors/haproxy
1
0
Fork 0
mirror of http://git.haproxy.org/git/haproxy.git/ synced 2024-12-27 15:12:11 +00:00
Code Issues Packages Projects Releases Wiki Activity

MINOR: opentracing: transfer of context names without prefix

Browse Source 
In order to enable the assignment of a context name, and yet exclude the
use of that name (prefix in this case) when extracting the context from
the HTTP header, a special character '-' has been added, which can be
specified at the beginning of the prefix.

So let's say if we look at examples of the fe-be configuration, we can
transfer the context via an HTTP header without a prefix like this:

  fe/ot.cfg:
        ..
        span "HAProxy session"
            inject "" use-headers
        event on-backend-http-request

Such a context can be read in another process using a name that has a
special '-' sign at the beginning:

  be/ot.cfg:
    ot-scope frontend_http_request
        extract "-ot-ctx" use-headers
        span "HAProxy session" child-of "-ot-ctx" root
        ..

This means that the context name will be '-ot-ctx' but it will not be
used when extracting data from HTTP headers.

Of course, if the context does not have a prefix set, all HTTP headers
will be inserted into the OpenTracing library as context.  All of the
above will only work correctly if that library can figure out what is
relevant to the context and what is not.
This commit is contained in:
Miroslav Zagorac 2021-04-14 11:47:28 +02:00 committed by Willy Tarreau
parent 4b3eb0a940
commit a8bdf2b655
2 changed files with 14 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
addons/ot/include/parser.h
View File

@ -38,6 +38,7 @@
#define FLT_OT_PARSE_SPAN_REF_CHILD "child-of"
#define FLT_OT_PARSE_SPAN_REF_FOLLOWS "follows-from"
#define FLT_OT_PARSE_CTX_AUTONAME "-"
#define FLT_OT_PARSE_CTX_IGNORE_NAME '-'
#define FLT_OT_PARSE_CTX_USE_HEADERS "use-headers"
#define FLT_OT_PARSE_CTX_USE_VARS "use-vars"
#define FLT_OT_PARSE_OPTION_HARDERR "hard-errors"

13
addons/ot/src/http.c
View File

@ -99,6 +99,19 @@ struct otc_text_map *flt_ot_http_headers_get(struct channel *chn, const char *pr
if (chn == NULL)
FLT_OT_RETURN(retptr);
/*
* The keyword 'inject' allows you to define the name of the OpenTracing
* context without using a prefix. In that case all HTTP headers are
* transferred because it is not possible to separate them from the
* OpenTracing context (this separation is usually done via a prefix).
*
* When using the 'extract' keyword, the context name must be specified.
* To allow all HTTP headers to be extracted, the first character of
* that name must be set to FLT_OT_PARSE_CTX_IGNORE_NAME.
*/
if (FLT_OT_STR_ISVALID(prefix) && (*prefix == FLT_OT_PARSE_CTX_IGNORE_NAME))
prefix_len = 0;
htx = htxbuf(&(chn->buf));
for (pos = htx_get_first(htx); pos != -1; pos = htx_get_next(htx, pos)) {