Add 128-bit trace id generation and propagation via _dd.p.tid (#1875)

* Add 128 bit trace_id generation and propagation via _dd.p.tid Signed-off-by: Bob Weinand <bob.weinand@datadoghq.com> * Save start time as seconds on the highest 32 bits of the trace_id Signed-off-by: Bob Weinand <bob.weinand@datadoghq.com> * Apply suggestions from review Signed-off-by: Bob Weinand <bob.weinand@datadoghq.com> --------- Signed-off-by: Bob Weinand <bob.weinand@datadoghq.com>
DataDog · Feb 3, 2023 · fed56e0 · fed56e0
1 parent f59dc7d
commit fed56e0
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Showing 8 changed files with 78 additions and 9 deletions.
diff --git a/ext/configuration.h b/ext/configuration.h
@@ -113,6 +113,7 @@ extern bool runtime_config_first_init;
     CONFIG(BOOL, DD_LOG_BACKTRACE, "false")                                                                    \
     CONFIG(BOOL, DD_TRACE_GENERATE_ROOT_SPAN, "true", .ini_change = ddtrace_span_alter_root_span_config)       \
     CONFIG(INT, DD_TRACE_SPANS_LIMIT, "1000")                                                                  \
+    CONFIG(BOOL, DD_TRACE_128_BIT_TRACEID_GENERATION_ENABLED, "false")                                         \
     CONFIG(INT, DD_TRACE_AGENT_MAX_CONSECUTIVE_FAILURES,                                                       \
            DD_CFG_EXPSTR(DD_TRACE_CIRCUIT_BREAKER_DEFAULT_MAX_CONSECUTIVE_FAILURES))                           \
     CONFIG(INT, DD_TRACE_AGENT_ATTEMPT_RETRY_TIME_MSEC,                                                        \

diff --git a/ext/ddtrace.c b/ext/ddtrace.c
@@ -1856,7 +1856,10 @@ static void dd_apply_propagated_values_to_existing_spans(void) {
     while (span) {
         zend_array *meta = ddtrace_spandata_property_meta(span);
         if (!DDTRACE_G(distributed_trace_id).low && !DDTRACE_G(distributed_trace_id).high) {
-            span->trace_id = (ddtrace_trace_id){ .high = 0, .low = span->root->span_id };
+            span->trace_id = (ddtrace_trace_id) {
+                .low = span->root->span_id,
+                .time = get_DD_TRACE_128_BIT_TRACEID_GENERATION_ENABLED() ? span->start / UINT64_C(1000000000) : 0,
+            };
         } else {
             span->trace_id = DDTRACE_G(distributed_trace_id);
         }
@@ -2415,6 +2418,12 @@ void ddtrace_read_distributed_tracing_ids(bool (*read_header)(zai_string_view, c
         }
     }
 
+    zval *tidzv = zend_hash_str_find(&DDTRACE_G(root_span_tags_preset), ZEND_STRL("_dd.p.tid"));
+    if (tidzv && DDTRACE_G(distributed_trace_id).low) {
+        DDTRACE_G(distributed_trace_id).high = ddtrace_parse_hex_span_id(tidzv);
+        zend_hash_str_del(&DDTRACE_G(root_span_tags_preset), ZEND_STRL("_dd.p.tid"));
+    }
+
     if (priority_sampling != DDTRACE_PRIORITY_SAMPLING_UNKNOWN) {
         if (!DDTRACE_G(active_stack)->root_span) {
             DDTRACE_G(propagated_priority_sampling) = DDTRACE_G(default_priority_sampling) = priority_sampling;

diff --git a/ext/ddtrace.h b/ext/ddtrace.h
@@ -75,7 +75,16 @@ typedef struct {
 
 typedef struct {
     uint64_t low;
-    uint64_t high;
+    union {
+        uint64_t high;
+        struct {
+            ZEND_ENDIAN_LOHI(
+                uint32_t padding // zeroes
+            ,
+                uint32_t time
+            )
+        };
+    };
 } ddtrace_trace_id;
 
 // clang-format off

diff --git a/ext/serializer.c b/ext/serializer.c
@@ -745,6 +745,10 @@ static void _serialize_meta(zval *el, ddtrace_span_data *span) {
         add_assoc_long(el, "error", 1);
     }
 
+    if (span->trace_id.high) {
+        add_assoc_str(meta, "_dd.p.tid", zend_strpprintf(0, "%" PRIx64, span->trace_id.high));
+    }
+
     if (zend_array_count(Z_ARRVAL_P(meta))) {
         add_assoc_zval(el, "meta", meta);
     } else {

diff --git a/ext/span.c b/ext/span.c
@@ -120,7 +120,7 @@ void ddtrace_free_span_stacks(bool silent) {
 static uint64_t _get_nanoseconds(bool monotonic_clock) {
     struct timespec time;
     if (clock_gettime(monotonic_clock ? CLOCK_MONOTONIC : CLOCK_REALTIME, &time) == 0) {
-        return time.tv_sec * 1000000000L + time.tv_nsec;
+        return time.tv_sec * UINT64_C(1000000000) + time.tv_nsec;
     }
     return 0;
 }
@@ -142,6 +142,11 @@ void ddtrace_open_span(ddtrace_span_data *span) {
     // All open spans hold a ref to their stack
     ZVAL_OBJ_COPY(&span->property_stack, &stack->std);
 
+    span->duration_start = _get_nanoseconds(USE_MONOTONIC_CLOCK);
+    // Start time is nanoseconds from unix epoch
+    // @see https://docs.datadoghq.com/api/?lang=python#send-traces
+    span->start = _get_nanoseconds(USE_REALTIME_CLOCK);
+
     span->span_id = ddtrace_generate_span_id();
     // if not a root span or the true root span (distributed tracing)
     bool root_span = DDTRACE_G(active_stack)->root_span == NULL;
@@ -158,12 +163,9 @@ void ddtrace_open_span(ddtrace_span_data *span) {
 set_trace_id_from_span_id:
         span->trace_id = (ddtrace_trace_id){
             .low = span->span_id,
+            .time = get_DD_TRACE_128_BIT_TRACEID_GENERATION_ENABLED() ? span->start / UINT64_C(1000000000) : 0,
         };
     }
-    span->duration_start = _get_nanoseconds(USE_MONOTONIC_CLOCK);
-    // Start time is nanoseconds from unix epoch
-    // @see https://docs.datadoghq.com/api/?lang=python#send-traces
-    span->start = _get_nanoseconds(USE_REALTIME_CLOCK);
 
     ddtrace_span_data *parent_span = DDTRACE_G(active_stack)->active;
     ZVAL_OBJ(&DDTRACE_G(active_stack)->property_active, &span->std);

diff --git a/ext/tracer_tag_propagation/tracer_tag_propagation.c b/ext/tracer_tag_propagation/tracer_tag_propagation.c
@@ -102,6 +102,7 @@ zend_string *ddtrace_format_propagated_tags(void) {
     // we propagate all tags on the current root span which were originally propagated, including the explicitly
     // defined tags here
     zend_hash_str_del(&DDTRACE_G(propagated_root_span_tags), ZEND_STRL("_dd.p.upstream_services"));
+    zend_hash_str_del(&DDTRACE_G(propagated_root_span_tags), ZEND_STRL("_dd.p.tid"));
     zend_hash_str_add_empty_element(&DDTRACE_G(propagated_root_span_tags), ZEND_STRL("_dd.p.dm"));
 
     zend_array *tags = &DDTRACE_G(root_span_tags_preset);
@@ -112,6 +113,11 @@ zend_string *ddtrace_format_propagated_tags(void) {
 
     smart_str taglist = {0};
 
+    ddtrace_trace_id trace_id = ddtrace_peek_trace_id();
+    if (trace_id.high) {
+        smart_str_append_printf(&taglist, "_dd.p.tid=%" PRIx64, trace_id.high);
+    }
+
     zend_string *tagname;
     ZEND_HASH_FOREACH_STR_KEY(&DDTRACE_G(propagated_root_span_tags), tagname) {
         zval *tag = zend_hash_find(tags, tagname), error_zv = {0};

diff --git a/tests/ext/generate_128_bit_trace_id.phpt b/tests/ext/generate_128_bit_trace_id.phpt
@@ -0,0 +1,38 @@
+--TEST--
+Test 128 bit generation
+--ENV--
+DD_TRACE_GENERATE_ROOT_SPAN=0
+--FILE--
+<?php
+
+ini_set("datadog.trace.128_bit_traceid_generation_enabled", "1");
+DDTrace\start_span();
+var_dump(\DDTrace\trace_id() > 2 ** 64);
+
+ini_set("datadog.trace.128_bit_traceid_generation_enabled", "0");
+DDTrace\set_distributed_tracing_context(0, 0);
+var_dump(\DDTrace\trace_id() < 2 ** 64);
+
+ini_set("datadog.trace.128_bit_traceid_generation_enabled", "1");
+DDTrace\set_distributed_tracing_context(0, 0);
+var_dump(\DDTrace\trace_id() > 2 ** 64);
+$first_trace_id = \DDTrace\trace_id();
+DDTrace\close_span();
+
+ini_set("datadog.trace.128_bit_traceid_generation_enabled", "0");
+DDTrace\start_span();
+var_dump(\DDTrace\trace_id() < 2 ** 64);
+DDTrace\close_span();
+
+$spans = dd_trace_serialize_closed_spans();
+var_dump(!isset($spans[0]["meta"]["_dd.p.tid"]));
+var_dump(hexdec($spans[1]["meta"]["_dd.p.tid"]) == floor($spans[1]["start"] / 1000000000) * (1 << 32));
+
+?>
+--EXPECT--
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
diff --git a/tests/ext/integrations/curl/distributed_tracing_curl_tracestate.phpt b/tests/ext/integrations/curl/distributed_tracing_curl_tracestate.phpt
@@ -45,9 +45,9 @@ echo 'Done.' . PHP_EOL;
 --EXPECTF--
 b3: 12345678901234567890123456789012-6543210987654321-d
 traceparent: 00-12345678901234567890123456789012-6543210987654321-01
-tracestate: dd=o:phpt-test;s:2;t.test:qvalue;unknown1:val;unknown2:1,foo=bar:;=,baz=qux
+tracestate: dd=o:phpt-test;s:2;t.tid:1234567890123456;t.test:qvalue;unknown1:val;unknown2:1,foo=bar:;=,baz=qux
 x-datadog-origin: phpt-test
-x-datadog-tags: _dd.p.test=qvalue
+x-datadog-tags: _dd.p.tid=1234567890123456,_dd.p.test=qvalue
 bool(false)
 Done.
 No finished traces to be sent to the agent