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

components-rs/sidecar.h

@@ -225,6 +225,14 @@ 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 default service name for the session. Empty = user-defined
+ * (sidecar emits `svc.user:true`); non-empty = auto-resolved with that name
+ * (sidecar emits `svc.auto:<name>`).
+ */
+ddog_MaybeError ddog_sidecar_session_set_default_service_name(struct ddog_SidecarTransport **transport,
+                                                              ddog_CharSlice default_service_name);
+
 /**
  * Enqueues a telemetry log action to be processed internally.
  * Non-blocking. Logs might be dropped if the internal queue is full.

ext/serializer.c

@@ -1578,7 +1578,40 @@ ddog_SpanBytes *ddtrace_serialize_span_to_rust_span(ddtrace_span_data *span, ddo
     if (is_first_span) {
         zend_string *process_tags = ddtrace_process_tags_get_serialized();
         if (ZSTR_LEN(process_tags)) {
-            ddog_add_str_span_meta_zstr(rust_span, "_dd.tags.process", process_tags);
+            // svc.* must be derived per span: process_tags are process-global but DD_SERVICE is request-local.
+            zend_string *dd_service = get_DD_SERVICE();
+            bool has_user_service = dd_service && ZSTR_LEN(dd_service) > 0;
+            zend_string *default_svc = NULL;
+            const char *svc_auto_normalized = NULL;
+            if (!has_user_service) {
+                default_svc = ddtrace_default_service_name();
+                if (default_svc) {
+                    svc_auto_normalized = ddog_normalize_process_tag_value((ddog_CharSlice){
+                        .ptr = ZSTR_VAL(default_svc), .len = ZSTR_LEN(default_svc)
+                    });
+                }
+            }
+            if (has_user_service || svc_auto_normalized) {
+                smart_str combined = {0};
+                smart_str_append(&combined, process_tags);
+                if (has_user_service) {
+                    smart_str_appends(&combined, ",svc.user:true");
+                } else {
+                    smart_str_appends(&combined, ",svc.auto:");
+                    smart_str_appends(&combined, svc_auto_normalized);
+                }
+                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 (svc_auto_normalized) {
+                ddog_free_normalized_tag_value(svc_auto_normalized);
+            }
+            if (default_svc) {
+                zend_string_release(default_svc);
+            }
         }
     }
 

ext/sidecar.c

@@ -7,6 +7,7 @@
 #include "ddtrace_export.h"
 #include "dogstatsd.h"
 #include "logging.h"
+#include "serializer.h"
 #include <components-rs/common.h>
 #include <components-rs/ddtrace.h>
 #include <components-rs/sidecar.h>
@@ -149,6 +150,27 @@ void ddtrace_sidecar_update_process_tags(void) {
     }
 
     ddog_sidecar_session_set_process_tags(&DDTRACE_G(sidecar), process_tags);
+
+    zend_string *dd_service = get_DD_SERVICE();
+    if (dd_service && ZSTR_LEN(dd_service) > 0) {
+        ddtrace_ffi_try("Failed updating sidecar default service name",
+            ddog_sidecar_session_set_default_service_name(&DDTRACE_G(sidecar),
+                DDOG_CHARSLICE_C("")));
+    } else {
+        zend_string *default_svc = ddtrace_default_service_name();
+        if (default_svc) {
+            const char *normalized = ddog_normalize_process_tag_value((ddog_CharSlice){
+                .ptr = ZSTR_VAL(default_svc), .len = ZSTR_LEN(default_svc)
+            });
+            if (normalized) {
+                ddtrace_ffi_try("Failed updating sidecar default service name",
+                    ddog_sidecar_session_set_default_service_name(&DDTRACE_G(sidecar),
+                        (ddog_CharSlice){ .ptr = normalized, .len = strlen(normalized) }));
+                ddog_free_normalized_tag_value(normalized);
+            }
+            zend_string_release(default_svc);
+        }
+    }
 }
 
 static ddog_SidecarTransport *dd_sidecar_connection_factory_ex(bool is_fork);
@@ -498,6 +520,8 @@ void ddtrace_sidecar_handle_fork(void) {
 
     if (DDTRACE_G(sidecar)) {
         ddtrace_sidecar_for_signal = DDTRACE_G(sidecar);
+        // Fresh post-fork session has no svc.* source — re-push it.
+        ddtrace_sidecar_update_process_tags();
     }
 #endif
 }

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';
+    }
+}

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');

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);
+    }
 }

tests/ext/process_tags.phpt

@@ -47,6 +47,6 @@ if (isset($spans[1]['meta']['_dd.process_tags'])) {
 ?>
 --EXPECTF--
 Process tags present in root span: YES
-Process tags: entrypoint.basedir:ext,entrypoint.name:process_tags,entrypoint.type:script,entrypoint.workdir:%s,runtime.sapi:cli
+Process tags: entrypoint.basedir:ext,entrypoint.name:process_tags,entrypoint.type:script,entrypoint.workdir:%s,runtime.sapi:cli,svc.auto:process_tags.php
 Keys sorted: YES
 Process tags present in child span: NO

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

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

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

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

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