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[PROF-14883] Publish thread context attribute keys at process start #576

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[PROF-14883] Publish thread context attribute keys at process start #576

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57 changes: 0 additions & 57 deletions ddprof-lib/src/main/cpp/context_api.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -18,15 +18,10 @@
#include "context.h"
#include "guards.h"
#include "otel_context.h"
#include "otel_process_ctx.h"
#include "profiler.h"
#include "thread.h"
#include <cstring>

// Reserved attribute index for local root span ID in OTEL attrs_data.
// Only used within this translation unit; not part of the public ContextApi header.
static const uint8_t LOCAL_ROOT_SPAN_ATTR_INDEX = 0;

/**
* Initialize context TLS for the current thread on first use.
* Must be called with signals blocked to prevent musl TLS deadlock:
Expand Down Expand Up @@ -71,55 +66,3 @@ Context ContextApi::snapshot() {
size_t numAttrs = Profiler::instance()->numContextAttributes();
return thrd->snapshotContext(numAttrs);
}

void ContextApi::registerAttributeKeys(const char** keys, int count) {
// Clip to DD_TAGS_CAPACITY: that is the actual sidecar slot limit and the
// maximum keyIndex accepted by ThreadContext.setContextAttribute.
int n = count < (int)DD_TAGS_CAPACITY ? count : (int)DD_TAGS_CAPACITY;

// Build NULL-terminated key array for the process context config.
// Index LOCAL_ROOT_SPAN_ATTR_INDEX (0) is reserved for local_root_span_id; user keys start at index 1.
// otel_process_ctx_publish copies all strings, so no strdup is needed.
const char* key_ptrs[DD_TAGS_CAPACITY + 2]; // +1 reserved, +1 null
key_ptrs[LOCAL_ROOT_SPAN_ATTR_INDEX] = "datadog.local_root_span_id";
for (int i = 0; i < n; i++) {
key_ptrs[i + 1] = keys[i];
}
key_ptrs[n + 1] = nullptr;

otel_thread_ctx_config_data config = {
.schema_version = "tlsdesc_v1_dev",
.attribute_key_map = key_ptrs,
};

#ifndef OTEL_PROCESS_CTX_NO_READ
otel_process_ctx_read_result read_result = otel_process_ctx_read();
if (read_result.success) {
otel_process_ctx_data data = {
.deployment_environment_name = read_result.data.deployment_environment_name,
.service_instance_id = read_result.data.service_instance_id,
.service_name = read_result.data.service_name,
.service_version = read_result.data.service_version,
.telemetry_sdk_language = read_result.data.telemetry_sdk_language,
.telemetry_sdk_version = read_result.data.telemetry_sdk_version,
.telemetry_sdk_name = read_result.data.telemetry_sdk_name,
.resource_attributes = read_result.data.resource_attributes,
.extra_attributes = read_result.data.extra_attributes,
.thread_ctx_config = &config,
};

otel_process_ctx_publish(&data);
otel_process_ctx_read_drop(&read_result);
}
#endif
}

void ContextApi::registerAttributeKeys(const std::vector<std::string>& keys) {
// Clip to DD_TAGS_CAPACITY before materializing C string pointers.
size_t n = keys.size() < DD_TAGS_CAPACITY ? keys.size() : DD_TAGS_CAPACITY;
const char* key_ptrs[DD_TAGS_CAPACITY];
for (size_t i = 0; i < n; i++) {
key_ptrs[i] = keys[i].c_str();
}
registerAttributeKeys(key_ptrs, (int)n);
}
19 changes: 0 additions & 19 deletions ddprof-lib/src/main/cpp/context_api.h
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Expand Up @@ -20,8 +20,6 @@
#include "arch.h"
#include "context.h"
#include <cstdint>
#include <string>
#include <vector>

class ProfiledThread;

Expand Down Expand Up @@ -69,23 +67,6 @@ class ContextApi {
* @return A Context struct representing the current thread's context
*/
static Context snapshot();

/**
* Register attribute key names and publish them in the process context.
* Must be called before setAttribute().
* Keys beyond DD_TAGS_CAPACITY are silently clipped.
*
* @param keys Array of key name strings
* @param count Number of keys (clipped to DD_TAGS_CAPACITY)
*/
static void registerAttributeKeys(const char** keys, int count);

/**
* std::vector overload of registerAttributeKeys, used from the C++ start
* path so that the attributes=... CLI argument auto-publishes the OTEP
* attribute_key_map without requiring an explicit Java-side call.
*/
static void registerAttributeKeys(const std::vector<std::string>& keys);
};

#endif /* _CONTEXT_API_H */
69 changes: 38 additions & 31 deletions ddprof-lib/src/main/cpp/javaApi.cpp
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Expand Up @@ -438,7 +438,8 @@ Java_com_datadoghq_profiler_OTelContext_setProcessCtx0(JNIEnv *env,
jstring runtime_id,
jstring service,
jstring version,
jstring tracer_version
jstring tracer_version,
jobjectArray attribute_keys
) {
JniString env_str(env, env_data);
JniString hostname_str(env, hostname);
Expand All @@ -449,6 +450,39 @@ Java_com_datadoghq_profiler_OTelContext_setProcessCtx0(JNIEnv *env,

const char *host_name_attrs[] = {"host.name", hostname_str.c_str(), NULL};

// Build the thread context attribute_key_map published alongside the process
// context: index 0 is the reserved datadog.local_root_span_id slot, followed by
// the caller-provided keys (clipped to DD_TAGS_CAPACITY)
int count = (attribute_keys != nullptr) ? env->GetArrayLength(attribute_keys) : 0;
int n = count < (int)DD_TAGS_CAPACITY ? count : (int)DD_TAGS_CAPACITY;
if (count > n) {
LOG_WARN("setProcessContext: %d attribute keys requested but capacity is %d; extra keys will be ignored",
count, (int)DD_TAGS_CAPACITY);
}

const char *key_ptrs[DD_TAGS_CAPACITY + 2]; // +1 reserved slot, +1 NULL terminator
JniString *jni_keys[DD_TAGS_CAPACITY];
int built = 0;
key_ptrs[0] = "datadog.local_root_span_id";
for (int i = 0; i < n; i++) {
jstring jstr = (jstring)env->GetObjectArrayElement(attribute_keys, i);
if (jstr == nullptr) {
// A null key would corrupt the index mapping; abort the publish.
for (int j = 0; j < built; j++) delete jni_keys[j];
Log::warn("setProcessContext: null attribute key at index %d; skipping publish", i);
return;
}
jni_keys[built] = new JniString(env, jstr);
key_ptrs[i + 1] = jni_keys[built]->c_str();
built++;
}
key_ptrs[n + 1] = nullptr;

otel_thread_ctx_config_data thread_ctx_config = {
.schema_version = "tlsdesc_v1_dev",
.attribute_key_map = key_ptrs,
};

otel_process_ctx_data data = {
.deployment_environment_name = env_str.c_str(),
.service_instance_id = runtime_id_str.c_str(),
Expand All @@ -459,13 +493,15 @@ Java_com_datadoghq_profiler_OTelContext_setProcessCtx0(JNIEnv *env,
.telemetry_sdk_name = "dd-trace-java",
.resource_attributes = host_name_attrs,
.extra_attributes = NULL,
.thread_ctx_config = NULL // Set later by ContextApi::registerAttributeKeys() when keys are known
.thread_ctx_config = &thread_ctx_config
};

otel_process_ctx_result result = otel_process_ctx_publish(&data);
if (!result.success) {
Log::warn("Failed to publish process context: %s", result.error_message);
}

for (int i = 0; i < built; i++) delete jni_keys[i];
}

extern "C" DLLEXPORT jobject JNICALL
Expand Down Expand Up @@ -599,35 +635,6 @@ Java_com_datadoghq_profiler_ThreadContext_registerConstant0(JNIEnv* env, jclass
return encoding == 0 ? -1 : (jint)encoding;
}

extern "C" DLLEXPORT void JNICALL
Java_com_datadoghq_profiler_OTelContext_registerAttributeKeys0(JNIEnv* env, jclass unused, jobjectArray keys) {
int count = (keys != nullptr) ? env->GetArrayLength(keys) : 0;
int n = count < (int)DD_TAGS_CAPACITY ? count : (int)DD_TAGS_CAPACITY;
if (count > n) {
LOG_WARN("registerAttributeKeys: %d keys requested but capacity is %d; extra keys will be ignored",
count, (int)DD_TAGS_CAPACITY);
}

const char* key_ptrs[DD_TAGS_CAPACITY];
JniString* jni_strings[DD_TAGS_CAPACITY];

for (int i = 0; i < n; i++) {
jstring jstr = (jstring)env->GetObjectArrayElement(keys, i);
if (jstr == nullptr) {
for (int j = 0; j < i; j++) delete jni_strings[j];
return;
}
jni_strings[i] = new JniString(env, jstr);
key_ptrs[i] = jni_strings[i]->c_str();
}

// Always call registerAttributeKeys even with n==0 so the reserved
// datadog.local_root_span_id key (index 0) is published in the process context.
ContextApi::registerAttributeKeys(key_ptrs, n);

for (int i = 0; i < n; i++) delete jni_strings[i];
}

// ---- test and debug utilities
extern "C" DLLEXPORT void JNICALL
Java_com_datadoghq_profiler_JavaProfiler_testlog(JNIEnv* env, jclass unused, jstring msg) {
Expand Down
4 changes: 0 additions & 4 deletions ddprof-lib/src/main/cpp/profiler.cpp
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Expand Up @@ -9,7 +9,6 @@
#include "asyncSampleMutex.h"
#include "mallocTracer.h"
#include "context.h"
#include "context_api.h"
#include "guards.h"
#include "common.h"
#include "counters.h"
Expand Down Expand Up @@ -1355,9 +1354,6 @@ Error Profiler::start(Arguments &args, bool reset) {
JfrMetadata::reset();
JfrMetadata::initialize(args._context_attributes);
_num_context_attributes = args._context_attributes.size();
// Initialize the OTel thread context so external profilers can decode
// the per-thread context, including custom attributes
ContextApi::registerAttributeKeys(args._context_attributes);
error = _jfr.start(args, reset);
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if (error) {
disableEngines();
Expand Down
57 changes: 15 additions & 42 deletions ddprof-lib/src/main/java/com/datadoghq/profiler/OTelContext.java
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Expand Up @@ -145,7 +145,7 @@ public OTelContext(String libLocation, String scratchDir, Consumer<Throwable> er
* Reads the currently published OpenTelemetry process context, if any.
*
* <p>This method attempts to read back the process context that was previously
* published via {@link #setProcessContext(String, String, String, String, String, String)}. This is
* published via {@link #setProcessContext(String, String, String, String, String, String, String[])}. This is
* primarily useful for debugging and testing purposes.
*
* <p><b>Platform Support:</b> Currently only supported on Linux. On other
Expand Down Expand Up @@ -193,7 +193,8 @@ public ProcessContext readProcessContext() {
* "instance-12345", // runtime-id
* "my-service", // service
* "1.0.0", // version
* "3.5.0" // tracer-version
* "3.5.0", // tracer-version
* new String[] {"http.route", "db.system"} // thread-context attribute keys
* );
* }</pre>
*
Expand All @@ -215,58 +216,30 @@ public ProcessContext readProcessContext() {
* @param tracerVersion the version of the tracer as defined by OpenTelemetry
* semantic conventions (telemetry.sdk.version). Must not be null.
* Examples: "3.5.0", "4.2.0"
* *
* @param attributeKeys the thread-context attribute key names whose per-thread
* values are recorded in the OTEP thread-local record (e.g.
* "http.route", "db.system"). Published in the process context's
* thread_ctx_config as the attribute_key_map, preceded by the
* reserved datadog.local_root_span_id slot. Must not be null
* (may be empty); keys beyond capacity are clipped. Order must
* match the indices used with
* {@link ThreadContext#setContextAttribute(int, String)}.
*
* @see <a href="https://opentelemetry.io/docs/specs/semconv/registry/attributes/service/">OpenTelemetry Service Attributes</a>
* @see <a href="https://opentelemetry.io/docs/specs/semconv/registry/attributes/deployment/">OpenTelemetry Deployment Attributes</a>
*/
public void setProcessContext(String env, String hostname, String runtimeId, String service, String version, String tracerVersion) {
public void setProcessContext(String env, String hostname, String runtimeId, String service, String version, String tracerVersion, String[] attributeKeys) {
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if (!libraryLoadResult.succeeded) {
return;
}
try {
lock.writeLock().lock();
setProcessCtx0(env, hostname, runtimeId, service, version, tracerVersion);
setProcessCtx0(env, hostname, runtimeId, service, version, tracerVersion, attributeKeys);
} finally {
lock.writeLock().unlock();
}
}

/**
* Registers attribute key names for the thread context.
*
* <p>These keys define the attribute_key_map in the process context's
* thread_ctx_config. In OTEL mode, attribute values set via
* {@link ThreadContext#setContextAttribute(int, String)} are encoded
* with the key index corresponding to position in this array.
*
* <p>Calling this method explicitly is <b>optional</b> when the profiler
* is started with the {@code attributes=...} argument (e.g.
* {@code execute("start,attributes=http.route;db.system,...")}); the
* native start path auto-registers those keys.
*
* <p>This method reads the currently published process context and
* republishes it with thread_ctx_config attached. It must therefore be
* called <b>after</b>
* {@link #setProcessContext(String, String, String, String, String, String)};
* if no process context has been published yet, the registration is a
* no-op for the process-level attribute_key_map (per-thread
* setContextAttribute writes still work). Conversely, calling
* setProcessContext after this method drops the previously published
* thread_ctx_config — re-register the keys after each setProcessContext
* if you need them to persist.
*
* <p>Must be called before any calls to setContextAttribute.
*
* @param keys Attribute key names (e.g. "http.route", "db.system")
*/
public void registerAttributeKeys(String... keys) {
if (!libraryLoadResult.succeeded) {
return;
}
registerAttributeKeys0(keys);
}

private static native void setProcessCtx0(String env, String hostname, String runtimeId, String service, String version, String tracerVersion);
private static native void setProcessCtx0(String env, String hostname, String runtimeId, String service, String version, String tracerVersion, String[] attributeKeys);
private static native ProcessContext readProcessCtx0();
private static native void registerAttributeKeys0(String[] keys);
}
2 changes: 0 additions & 2 deletions ...h/java/com/datadoghq/profiler/stresstest/scenarios/throughput/ThreadContextBenchmark.java
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Expand Up @@ -16,7 +16,6 @@
package com.datadoghq.profiler.stresstest.scenarios.throughput;

import com.datadoghq.profiler.JavaProfiler;
import com.datadoghq.profiler.OTelContext;
import com.datadoghq.profiler.ThreadContext;
import java.nio.file.Files;
import java.nio.file.Path;
Expand Down Expand Up @@ -64,7 +63,6 @@ public void setup() throws Exception {
profiler = JavaProfiler.getInstance();
Path jfr = Files.createTempFile("bench", ".jfr");
profiler.execute("start,cpu=10ms,attributes=http.route,jfr,file=" + jfr.toAbsolutePath());
OTelContext.getInstance().registerAttributeKeys("http.route");
}
}

Expand Down
9 changes: 0 additions & 9 deletions ddprof-test/src/test/java/com/datadoghq/profiler/context/OtelContextStorageModeTest.java
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Expand Up @@ -16,7 +16,6 @@
package com.datadoghq.profiler.context;

import com.datadoghq.profiler.JavaProfiler;
import com.datadoghq.profiler.OTelContext;
import com.datadoghq.profiler.ThreadContext;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeAll;
Expand Down Expand Up @@ -88,9 +87,6 @@ public void testOtelModeCustomAttributes() throws Exception {
profiler.execute(String.format("start,cpu=1ms,attributes=http.route;db.system,jfr,file=%s", jfrFile.toAbsolutePath()));
profilerStarted = true;

// Register attribute keys
OTelContext.getInstance().registerAttributeKeys("http.route", "db.system");

long localRootSpanId = 0x1111222233334444L;
long spanId = 0xAAAABBBBCCCCDDDDL;
profiler.setContext(localRootSpanId, spanId, 0L, 0x9999L);
Expand Down Expand Up @@ -121,8 +117,6 @@ public void testOtelModeAttributeOverflow() throws Exception {
profiler.execute(String.format("start,cpu=1ms,attributes=k0;k1;k2;k3;k4,jfr,file=%s", jfrFile.toAbsolutePath()));
profilerStarted = true;

OTelContext.getInstance().registerAttributeKeys("k0", "k1", "k2", "k3", "k4");

profiler.setContext(0x2L, 0x1L, 0L, 0x3L);

ThreadContext ctx = profiler.getThreadContext();
Expand Down Expand Up @@ -212,8 +206,6 @@ public void testSpanTransitionClearsAttributes() throws Exception {
profiler.execute(String.format("start,cpu=1ms,attributes=http.route,jfr,file=%s", jfrFile.toAbsolutePath()));
profilerStarted = true;

OTelContext.getInstance().registerAttributeKeys("http.route");

// Span A: set a custom attribute
profiler.setContext(0x1L, 0x1L, 0L, 0x1L);
ThreadContext ctx = profiler.getThreadContext();
Expand Down Expand Up @@ -256,7 +248,6 @@ public void testAttributeCacheIsolation() throws Exception {
Path jfrFile = Files.createTempFile("otel-attr-cache-iso", ".jfr");
profiler.execute(String.format("start,cpu=1ms,attributes=attr0,jfr,file=%s", jfrFile.toAbsolutePath()));
profilerStarted = true;
OTelContext.getInstance().registerAttributeKeys("attr0");

final String valueA = "FB"; // hashCode = 2236, slot 188
final String valueB = "Ea"; // hashCode = 2236, same slot
Expand Down
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