fix(axiom): handle locale for dt w3c priority

axiom/nr_distributed_trace.c

@@ -18,6 +18,7 @@
 #include "util_time.h"
 #include "util_strings.h"
 #include "util_logging.h"
+#include "util_number_converter.h"
 
 /*
  * Purpose : Helper function to assign a string value to a field.  This function
@@ -1164,6 +1165,8 @@ char* nr_distributed_trace_create_w3c_tracestate_header(
   const char* app_id;
   char* trace_context_header = NULL;
   char* sampled = "0";
+  double priority;
+  char* priority_buf = NULL;
 
   if (nrunlikely(NULL == dt)) {
     return NULL;
@@ -1197,11 +1200,20 @@ char* nr_distributed_trace_create_w3c_tracestate_header(
     sampled = "1";
   }
 
-  trace_context_header = nr_formatf(
-      "%s@nr=0-0-%s-%s-%s-%s-%s-%.6f-%" PRId64, trusted_account_key, account_id,
-      app_id, NRBLANKSTR(span_id), NRBLANKSTR(txn_id), sampled,
-      nr_distributed_trace_get_priority(dt),
-      (nr_get_time() / NR_TIME_DIVISOR_MS));
+  priority = nr_distributed_trace_get_priority(dt);
+
+  priority_buf = nr_priority_double_to_str(priority);
+
+  trace_context_header
+      = nr_formatf("%s@nr=0-0-%s-%s-%s-%s-%s-%s-%" PRId64, trusted_account_key,
+                   account_id, app_id, NRBLANKSTR(span_id), NRBLANKSTR(txn_id),
+                   sampled, priority_buf, (nr_get_time() / NR_TIME_DIVISOR_MS));
+
+  nr_free(priority_buf);
+
+  nrl_verbosedebug(NRL_CAT,
+                   "Outbound W3C TraceState Context Header generated: %s",
+                   trace_context_header);
 
   return trace_context_header;
 }

axiom/tests/test_distributed_trace.c

@@ -9,6 +9,7 @@
 #include "nr_txn.h"
 #include "nr_distributed_trace_private.h"
 #include "util_memory.h"
+#include <locale.h>
 
 static void test_distributed_trace_create_destroy(void) {
   // create a few instances to make sure state stays separate
@@ -1351,6 +1352,19 @@ static void test_create_trace_state_header(void) {
                         nr_strstr(result, expected));
   nr_free(result);
 
+  /*
+   * Test: locale is set to use `,` instead of `.` for decimal values
+   */
+  setlocale(LC_NUMERIC, "pl_PL");
+  dt->priority = 0.123456;
+  expected = "777@nr=0-0-1234-9876-123456789-meatball!-0-0.123456-";
+  result
+      = nr_distributed_trace_create_w3c_tracestate_header(dt, span_id, txn_id);
+  tlib_pass_if_not_null("locale should not affect priority formatting", 
+                        nr_strstr(result, expected));
+  nr_free(result);
+  setlocale(LC_NUMERIC, "en_US");
+
   nr_distributed_trace_destroy(&dt);
 }
 

axiom/util_number_converter.c

@@ -9,6 +9,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include "util_memory.h"
 #include "util_number_converter.h"
 #include "util_strings.h"
 
@@ -46,6 +47,22 @@ void nr_itoa(char* buf, size_t len, int x) {
   nr_strlcpy(buf, p, len);
 }
 
+#define PRIORITY_MAXLEN 6
+char* nr_priority_double_to_str(double value) {
+  char* buf = NULL;
+
+  buf = nr_formatf("%.6f", value);
+
+  for (int i = 0; i < PRIORITY_MAXLEN; i++) {
+    if (',' == buf[i]) {
+      buf[i] = '.';
+      break;
+    }
+  }
+
+  return buf;
+}
+
 int nr_double_to_str(char* buf, int buf_len, double input) {
   int i;
   int natural_width;

axiom/util_number_converter.h

@@ -25,6 +25,14 @@
  */
 extern void nr_itoa(char* buf, size_t len, int x);
 
+/*
+ * Purpose      Format double priority numbers to string.
+ *
+ * @param       value   double
+ * @return      char*   priority string buffer
+ */
+extern char* nr_priority_double_to_str(double value);
+
 /*
  * Purpose : Format double precision numbers.
  *

files/Dockerfile

@@ -54,6 +54,8 @@ RUN apt-get update && apt-get install -y \
   libc6-dev \
   libgtest-dev \
   libtool \
+  locales \
+  locales-all \
   make \
   perl \
   strace \

tests/integration/distributed_tracing/w3c/test_insert_dt_headers_locale.php

@@ -0,0 +1,37 @@
+<?php
+/*
+ * Copyright 2020 New Relic Corporation. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/*DESCRIPTION
+Tests that the locale is handled correctly in w3c dt tracestate header
+priority for locales that use `,` instead of `.` for decimal values
+*/
+
+/*INI
+newrelic.distributed_tracing_enabled = true
+newrelic.distributed_tracing_exclude_newrelic_header = false
+newrelic.cross_application_tracer.enabled = false
+*/
+
+/*EXPECT
+ok - insert function succeeded
+ok - preexisting header is present
+ok - newrelic header is present
+ok - tracestate header is present
+ok - traceparent header is present
+ok - locale handled correctly for w3c dt priority
+*/
+
+require_once(realpath (dirname ( __FILE__ )) . '/../../../include/tap.php');
+
+$headers = array('Accept-Language' => 'en-US,en;q=0.5');
+setlocale(LC_NUMERIC, 'fr_FR');
+tap_assert(newrelic_insert_distributed_trace_headers($headers), 'insert function succeeded');
+tap_assert(array_key_exists('Accept-Language', $headers), 'preexisting header is present');
+tap_assert(array_key_exists('newrelic', $headers), 'newrelic header is present');
+tap_assert(array_key_exists('tracestate', $headers), 'tracestate header is present');
+tap_assert(array_key_exists('traceparent', $headers), 'traceparent header is present');
+tap_refute(strpos($headers['tracestate'], ','), 'locale handled correctly for w3c dt priority');
+