feat(process-tags): signal service name source via svc.user/svc.auto (#3921)

Leiyks · bwoebi · web-flow · commit 18ca94641e5a · 2026-06-25T22:37:44.000+02:00
* feat(process-tags): signal service name source via svc.user/svc.auto Implements the PHP-tracer side of RFC "Signal Service Name Source via Process Tags". Surfaces one of two mutually-exclusive process tags so the backend can distinguish user-set vs tracer-auto-resolved service names: - svc.user:true — DD_SERVICE non-empty (env, INI, OTEL fallback, RC) - svc.auto:<name> — DD_SERVICE empty; tracer auto-resolved the default Per the RFC caveats, no conclusions are drawn from the absence of both. In ddtrace_serialize_span_to_rust_span's is_first_span block, the auto-resolved default name is read directly from the root span's property_service when its _dd.svc_src is absent (Service Override Source Attribution RFC: cleared svc_src ↔ service is the global default), avoiding a second pass through datadog_default_service_name(). Each span sees its own request's state — no FPM cross-request leak. datadog_sidecar_update_process_tags now also calls ddog_sidecar_session_set_default_service_name(transport, …): - Empty CharSlice → sidecar injects svc.user:true - Normalized default → sidecar injects svc.auto:<default> Injection happens at payload emission time in libdatadog (companion PR DataDog/libdatadog#2053), so telemetry / remote-config / runtime-info / stats payloads all see consistent svc.* tagging without baking it into the static process_tags string. - New CLI .phpt tests covering svc.user, svc.auto, OTEL fallback as user-defined, and ini_set-driven runtime mutation. - New web-SAPI test ProcessTagsWebTest::testSvcTagDoesNotLeakBetweenRequests proving the per-span design holds across FPM workers. - Existing process_tags.phpt / telemetry_process_tags.phpt updated to expect the appended svc.auto tag. * Apply suggestions from code review Co-authored-by: Bob Weinand <bobwei9@hotmail.com> * fix(svc_src): use datadog_convert_to_str + correct process_tags.phpt expectation - serializer.c: drop the temp zval and use datadog_convert_to_str directly (zend_string out, released by caller) per review. - process_tags.phpt: the test sets \$parent_span->service = 'test_service' manually, so the root span carries _dd.svc_src='m' (Service Override Source Attribution RFC); the per-span emission correctly skips svc.auto because the service isn't the global default. Remove the spurious svc.auto:process_tags.php from the expected output. --------- Co-authored-by: Bob Weinand <bobwei9@hotmail.com>
diff --git a/components-rs/sidecar.h b/components-rs/sidecar.h
@@ -227,6 +227,23 @@ ddog_MaybeError ddog_sidecar_session_set_config(struct ddog_SidecarTransport **t
 ddog_MaybeError ddog_sidecar_session_set_process_tags(struct ddog_SidecarTransport **transport,
                                                       const struct ddog_Vec_Tag *process_tags);
 
+/**
+ * Records the tracer's auto-resolved default service name for the session
+ * (process-bound; sidecar emits `svc.auto:<name>` when `DD_SERVICE` is not
+ * currently set for the active request). Pass an empty `CharSlice` to clear.
+ */
+ddog_MaybeError ddog_sidecar_session_set_default_service_name(struct ddog_SidecarTransport **transport,
+                                                              ddog_CharSlice default_service_name);
+
+/**
+ * Records whether `DD_SERVICE` is currently set for the session (per-request
+ * mutable; refresh on each RINIT). When `true` the sidecar emits
+ * `svc.user:true`; when `false` it falls back to the previously-recorded
+ * `svc.auto:<name>` (if any).
+ */
+ddog_MaybeError ddog_sidecar_session_set_user_service_defined(struct ddog_SidecarTransport **transport,
+                                                              bool is_user_defined);
+
 /**
  * Enqueues a telemetry log action to be processed internally.
  * Non-blocking. Logs might be dropped if the internal queue is full.
diff --git a/ext/sidecar.c b/ext/sidecar.c
@@ -153,6 +153,31 @@ void datadog_sidecar_update_process_tags(void) {
     }
 
     ddog_sidecar_session_set_process_tags(&DATADOG_G(sidecar), process_tags);
+
+    // Session-bound, process-stable: the tracer's auto-resolved default name.
+    zend_string *default_svc = datadog_default_service_name();
+    if (default_svc) {
+        const char *normalized = ddog_normalize_process_tag_value(dd_zend_string_to_CharSlice(default_svc));
+        if (normalized) {
+            datadog_ffi_try("Failed updating sidecar default service name",
+                ddog_sidecar_session_set_default_service_name(&DATADOG_G(sidecar),
+                    (ddog_CharSlice){ .ptr = normalized, .len = strlen(normalized) }));
+            ddog_free_normalized_tag_value(normalized);
+        }
+        zend_string_release(default_svc);
+    }
+
+    datadog_sidecar_refresh_user_service_defined();
+}
+
+void datadog_sidecar_refresh_user_service_defined(void) {
+    if (!DATADOG_G(sidecar)) {
+        return;
+    }
+    zend_string *dd_service = get_DD_SERVICE();
+    bool is_defined = dd_service && ZSTR_LEN(dd_service) > 0;
+    datadog_ffi_try("Failed updating sidecar user-service-defined flag",
+        ddog_sidecar_session_set_user_service_defined(&DATADOG_G(sidecar), is_defined));
 }
 
 static void datadog_sidecar_setup_thread_mode(void);
@@ -799,6 +824,10 @@ void datadog_sidecar_rinit(void) {
     }
 
     ddtrace_sidecar_submit_span_data_direct_defaults(&DATADOG_G(sidecar), NULL);
+
+    if (get_global_DD_EXPERIMENTAL_PROPAGATE_PROCESS_TAGS_ENABLED()) {
+        datadog_sidecar_refresh_user_service_defined();
+    }
 }
 
 void datadog_sidecar_rshutdown(void) {
diff --git a/ext/sidecar.h b/ext/sidecar.h
@@ -47,6 +47,7 @@ void datadog_sidecar_handle_fork(void);
 bool datadog_sidecar_should_enable(ddog_RemoteConfigFlags *flags);
 void datadog_sidecar_ensure_active(void);
 void datadog_sidecar_update_process_tags(void);
+void datadog_sidecar_refresh_user_service_defined(void);
 void datadog_sidecar_finalize(bool clear_id);
 void datadog_sidecar_shutdown(void);
 void datadog_force_new_instance_id(void);
diff --git a/libdatadog b/libdatadog
@@ -1 +1 @@
-Subproject commit cd90e50a5b067cf77a3e06641d838bc4c6b62aba
+Subproject commit 6a6d4a535e9875a7b012ce3f00eb6929649c3fb5
diff --git a/tests/Frameworks/Custom/Version_Autoloaded/src/SetServiceController.php b/tests/Frameworks/Custom/Version_Autoloaded/src/SetServiceController.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace App;
+
+class SetServiceController
+{
+    public function render()
+    {
+        ini_set('datadog.service', 'request-svc');
+        header('Content-type: text/plain; charset=utf-8');
+        echo 'service set';
+    }
+}
diff --git a/tests/Frameworks/Custom/Version_Autoloaded/src/routes.php b/tests/Frameworks/Custom/Version_Autoloaded/src/routes.php
@@ -2,6 +2,7 @@
 
 return function(FastRoute\RouteCollector $r) {
     $r->addRoute('GET', '/simple', '\App\SimpleController');
+    $r->addRoute('GET', '/set_service', '\App\SetServiceController');
     $r->addRoute('GET', '/simple_view', '\App\SimpleViewController');
     $r->addRoute('GET', '/error', '\App\ErrorController');
     $r->addRoute('GET', '/telemetry', '\App\TelemetryFlushController');
diff --git a/tests/Integrations/Custom/Autoloaded/ProcessTagsWebTest.php b/tests/Integrations/Custom/Autoloaded/ProcessTagsWebTest.php
@@ -65,4 +65,28 @@ public function testProcessTagsEnabledForWebSapi()
         );
         $this->assertEquals($tags['entrypoint.type'], 'script');
     }
+
+    /**
+     * Proves the per-span svc.* design has no static-state leak between
+     * requests served by the same FPM worker: request 1 calls
+     * ini_set('datadog.service', ...) and must report svc.user:true; request 2
+     * reuses the same worker but does not override the service, and must
+     * report svc.auto:<default> (not the leaked svc.user from request 1).
+     */
+    public function testSvcTagDoesNotLeakBetweenRequests()
+    {
+        $tracesUser = $this->tracesFromWebRequest(function () {
+            return $this->call(new RequestSpec(__FUNCTION__ . '_user', 'GET', '/set_service', []));
+        });
+        $userTags = $tracesUser[0][0]['meta']['_dd.tags.process'];
+        $this->assertStringContainsString('svc.user:true', $userTags);
+        $this->assertStringNotContainsString('svc.auto:', $userTags);
+
+        $tracesAuto = $this->tracesFromWebRequest(function () {
+            return $this->call(new RequestSpec(__FUNCTION__ . '_auto', 'GET', '/simple', []));
+        });
+        $autoTags = $tracesAuto[0][0]['meta']['_dd.tags.process'];
+        $this->assertStringNotContainsString('svc.user', $autoTags);
+        $this->assertStringContainsString('svc.auto:', $autoTags);
+    }
 }
diff --git a/tests/ext/svc_auto_tag_cli.phpt b/tests/ext/svc_auto_tag_cli.phpt
@@ -0,0 +1,23 @@
+--TEST--
+Process tags include svc.auto:<default> when DD_SERVICE is unset (CLI)
+--ENV--
+DD_EXPERIMENTAL_PROPAGATE_PROCESS_TAGS_ENABLED=1
+DD_TRACE_GENERATE_ROOT_SPAN=0
+DD_TRACE_AUTO_FLUSH_ENABLED=0
+--FILE--
+<?php
+$span = \DDTrace\start_span();
+$span->name = 'op';
+\DDTrace\close_span();
+
+$spans = dd_trace_serialize_closed_spans();
+$processTags = $spans[0]['meta']['_dd.tags.process'];
+
+echo "has svc.user: " . (strpos($processTags, 'svc.user') !== false ? 'YES' : 'NO') . "\n";
+echo "has svc.auto: " . (strpos($processTags, 'svc.auto:') !== false ? 'YES' : 'NO') . "\n";
+echo "auto value matches script: " . (strpos($processTags, 'svc.auto:svc_auto_tag_cli.php') !== false ? 'YES' : 'NO') . "\n";
+?>
+--EXPECT--
+has svc.user: NO
+has svc.auto: YES
+auto value matches script: YES
diff --git a/tests/ext/svc_auto_tag_otel.phpt b/tests/ext/svc_auto_tag_otel.phpt
@@ -0,0 +1,24 @@
+--TEST--
+OTEL_SERVICE_NAME counts as user-defined (emits svc.user:true)
+--ENV--
+DD_EXPERIMENTAL_PROPAGATE_PROCESS_TAGS_ENABLED=1
+OTEL_SERVICE_NAME=otel-app
+DD_TRACE_GENERATE_ROOT_SPAN=0
+DD_TRACE_AUTO_FLUSH_ENABLED=0
+--FILE--
+<?php
+$span = \DDTrace\start_span();
+$span->name = 'op';
+\DDTrace\close_span();
+
+$spans = dd_trace_serialize_closed_spans();
+$processTags = $spans[0]['meta']['_dd.tags.process'];
+
+echo "DD_SERVICE resolved to: " . ini_get('datadog.service') . "\n";
+echo "has svc.user:true: " . (strpos($processTags, 'svc.user:true') !== false ? 'YES' : 'NO') . "\n";
+echo "has svc.auto:   : " . (strpos($processTags, 'svc.auto:') !== false ? 'YES' : 'NO') . "\n";
+?>
+--EXPECT--
+DD_SERVICE resolved to: otel-app
+has svc.user:true: YES
+has svc.auto:   : NO
diff --git a/tests/ext/svc_runtime_change.phpt b/tests/ext/svc_runtime_change.phpt
@@ -0,0 +1,37 @@
+--TEST--
+Changing datadog.service at runtime recomputes svc.user/svc.auto process tags per-span
+--ENV--
+DD_EXPERIMENTAL_PROPAGATE_PROCESS_TAGS_ENABLED=1
+DD_TRACE_GENERATE_ROOT_SPAN=0
+DD_TRACE_AUTO_FLUSH_ENABLED=0
+--FILE--
+<?php
+function assert_tags($label) {
+    $spans = dd_trace_serialize_closed_spans();
+    $tags = $spans[0]['meta']['_dd.tags.process'];
+    $hasUser = strpos($tags, 'svc.user:true') !== false;
+    $hasAuto = strpos($tags, 'svc.auto:') !== false;
+    echo "$label svc.user=" . ($hasUser ? 'YES' : 'NO') . " svc.auto=" . ($hasAuto ? 'YES' : 'NO') . "\n";
+}
+
+$span1 = \DDTrace\start_span();
+$span1->name = 'before';
+\DDTrace\close_span();
+assert_tags('BEFORE  ');
+
+ini_set('datadog.service', 'changed-svc');
+$span2 = \DDTrace\start_span();
+$span2->name = 'after_set';
+\DDTrace\close_span();
+assert_tags('AFTER   ');
+
+ini_restore('datadog.service');
+$span3 = \DDTrace\start_span();
+$span3->name = 'after_restore';
+\DDTrace\close_span();
+assert_tags('REVERTED');
+?>
+--EXPECT--
+BEFORE   svc.user=NO svc.auto=YES
+AFTER    svc.user=YES svc.auto=NO
+REVERTED svc.user=NO svc.auto=YES
diff --git a/tests/ext/svc_user_tag.phpt b/tests/ext/svc_user_tag.phpt
@@ -0,0 +1,22 @@
+--TEST--
+Process tags include svc.user:true when DD_SERVICE is set
+--ENV--
+DD_EXPERIMENTAL_PROPAGATE_PROCESS_TAGS_ENABLED=1
+DD_SERVICE=my-app
+DD_TRACE_GENERATE_ROOT_SPAN=0
+DD_TRACE_AUTO_FLUSH_ENABLED=0
+--FILE--
+<?php
+$span = \DDTrace\start_span();
+$span->name = 'op';
+\DDTrace\close_span();
+
+$spans = dd_trace_serialize_closed_spans();
+$processTags = $spans[0]['meta']['_dd.tags.process'];
+
+echo "has svc.user:true: " . (strpos($processTags, 'svc.user:true') !== false ? 'YES' : 'NO') . "\n";
+echo "has svc.auto:   : " . (strpos($processTags, 'svc.auto:') !== false ? 'YES' : 'NO') . "\n";
+?>
+--EXPECT--
+has svc.user:true: YES
+has svc.auto:   : NO
diff --git a/tests/ext/telemetry/telemetry_process_tags.phpt b/tests/ext/telemetry/telemetry_process_tags.phpt
@@ -46,7 +46,7 @@ if ($i == 300) {
 ?>
 --EXPECTF--
 Included
-string(%d) "entrypoint.basedir:telemetry,entrypoint.name:telemetry_process_tags,entrypoint.type:script,entrypoint.workdir:%s,runtime.sapi:cli"
+string(%d) "entrypoint.basedir:telemetry,entrypoint.name:telemetry_process_tags,entrypoint.type:script,entrypoint.workdir:%s,runtime.sapi:cli,svc.auto:telemetry_process_tags.php"
 --CLEAN--
 <?php
 
diff --git a/tracer/serializer.c b/tracer/serializer.c
@@ -1575,7 +1575,42 @@ ddog_SpanBytes *ddtrace_serialize_span_to_rust_span(ddtrace_span_data *span, ddo
     if (is_first_span) {
         zend_string *process_tags = datadog_process_tags_get_serialized();
         if (ZSTR_LEN(process_tags)) {
-            ddog_add_str_span_meta_zstr(rust_span, "_dd.tags.process", process_tags);
+            const char *svc_tag_appendix = NULL;
+            const char *normalized_default = NULL;
+            zend_string *dd_service = get_DD_SERVICE();
+
+            if (dd_service && ZSTR_LEN(dd_service)) {
+                svc_tag_appendix = ",svc.user:true";
+            } else {
+                zend_array *root_meta = ddtrace_property_array(&span->root->property_meta);
+                if (!zend_hash_str_exists(root_meta, ZEND_STRL("_dd.svc_src"))) {
+                    zend_string *root_svc = datadog_convert_to_str(&span->root->property_service);
+                    if (ZSTR_LEN(root_svc)) {
+                        normalized_default = ddog_normalize_process_tag_value(dd_zend_string_to_CharSlice(root_svc));
+                    }
+                    zend_string_release(root_svc);
+                }
+            }
+
+            if (svc_tag_appendix || normalized_default) {
+                smart_str combined = {0};
+                smart_str_append(&combined, process_tags);
+                if (svc_tag_appendix) {
+                    smart_str_appends(&combined, svc_tag_appendix);
+                } else {
+                    smart_str_appends(&combined, ",svc.auto:");
+                    smart_str_appends(&combined, normalized_default);
+                }
+                smart_str_0(&combined);
+                ddog_add_str_span_meta_zstr(rust_span, "_dd.tags.process", combined.s);
+                smart_str_free(&combined);
+            } else {
+                ddog_add_str_span_meta_zstr(rust_span, "_dd.tags.process", process_tags);
+            }
+
+            if (normalized_default) {
+                ddog_free_normalized_tag_value(normalized_default);
+            }
         }
     }
 
