otel: add header parsing and test call state

Enables Unit to parse the tracestate and traceparent headers and add it
to the list, as well as calls to nxt_otel_test_and_call_state.

Signed-off-by: Gabor Javorszky <g.javorszky@f5.com>
Signed-off-by: Ava Hahn <a.hahn@f5.com>

Co-authored-by: Ava Hahn <a.hahn@f5.com>

src/nxt_h1proto.c

@@ -178,6 +178,10 @@ static nxt_http_field_proc_t           nxt_h1p_fields[] = {
     { nxt_string("Content-Length"),    &nxt_http_request_content_length, 0 },
     { nxt_string("Authorization"),     &nxt_http_request_field,
         offsetof(nxt_http_request_t, authorization) },
+#if (NXT_HAVE_OTEL)
+    { nxt_string("Traceparent"),       &nxt_otel_parse_traceparent, 0 },
+    { nxt_string("Tracestate"),        &nxt_otel_parse_tracestate,  0 },
+#endif
 };
 
 
@@ -518,6 +522,10 @@ nxt_h1p_conn_request_init(nxt_task_t *task, void *obj, void *data)
             h1p->parser.discard_unsafe_fields = skcf->discard_unsafe_fields;
 
             nxt_h1p_conn_request_header_parse(task, c, h1p);
+#if (NXT_HAVE_OTEL)
+            nxt_otel_test_and_call_state(task, r);
+#endif
+
             return;
         }
 
@@ -1332,6 +1340,10 @@ nxt_h1p_request_header_send(nxt_task_t *task, nxt_http_request_t *r,
 
     nxt_debug(task, "h1p request header send");
 
+#if (NXT_HAVE_OTEL)
+    nxt_otel_test_and_call_state(task, r);
+#endif
+
     r->header_sent = 1;
     h1p = r->proto.h1;
     n = r->status;

src/nxt_http_request.c

@@ -7,6 +7,10 @@
 #include <nxt_router.h>
 #include <nxt_http.h>
 
+#if(NXT_HAVE_OTEL)
+#include <nxt_otel.h>
+#endif
+
 
 static nxt_int_t nxt_http_validate_host(nxt_str_t *host, nxt_mp_t *mp);
 static void nxt_http_request_start(nxt_task_t *task, void *obj, void *data);
@@ -319,6 +323,10 @@ nxt_http_request_start(nxt_task_t *task, void *obj, void *data)
 
     r = obj;
 
+#if (NXT_HAVE_OTEL)
+    nxt_otel_test_and_call_state(task, r);
+#endif
+
     r->state = &nxt_http_request_body_state;
 
     skcf = r->conf->socket_conf;
@@ -590,6 +598,10 @@ nxt_http_request_ready(nxt_task_t *task, void *obj, void *data)
     r = obj;
     action = r->conf->socket_conf->action;
 
+#if (NXT_HAVE_OTEL)
+    nxt_otel_test_and_call_state(task, r);
+#endif
+
     if (r->chunked) {
         ret = nxt_http_request_chunked_transform(r);
         if (nxt_slow_path(ret != NXT_OK)) {