perf(config): cache sys getenv

ext/otel_config.c

@@ -20,22 +20,22 @@ static void report_otel_cfg_telemetry_invalid(const char *otel_cfg, const char *
     }
 }
 
-static bool get_otel_value(zai_str str, zai_env_buffer buf, bool pre_rinit) {
-    if (zai_getenv_ex(str, buf, pre_rinit) == ZAI_ENV_SUCCESS) {
-        return true;
-    }
+static bool get_otel_value(zai_str str, zai_env_buffer *buf, bool pre_rinit) {
+    if (!pre_rinit && zai_sapi_getenv(str, buf) == ZAI_ENV_SUCCESS) return true;
+    zai_option_str sys = zai_sys_getenv(str);
+    if (zai_option_str_is_some(sys)) { buf->ptr = sys.ptr; buf->len = sys.len; return true; }
 
     zval *cfg = cfg_get_entry(str.ptr, str.len);
     if (cfg) {
         if (Z_TYPE_P(cfg) == IS_ARRAY) {
             zval *val;
-            char *off = buf.ptr;
+            char *off = buf->ptr;
             ZEND_HASH_FOREACH_VAL(Z_ARR_P(cfg), val) {
                 if (Z_TYPE_P(val) == IS_STRING) {
-                    if (off - buf.ptr + Z_STRLEN_P(val) + 2 >= ZAI_ENV_MAX_BUFSIZ) {
+                    if (off - buf->ptr + Z_STRLEN_P(val) + 2 >= ZAI_ENV_MAX_BUFSIZ) {
                         return false;
                     }
-                    if (off != buf.ptr) {
+                    if (off != buf->ptr) {
                         *off++ = ',';
                     }
                     memcpy(off, Z_STRVAL_P(val), Z_STRLEN_P(val));
@@ -46,29 +46,30 @@ static bool get_otel_value(zai_str str, zai_env_buffer buf, bool pre_rinit) {
         } else if (Z_STRLEN_P(cfg) == 0 || Z_STRLEN_P(cfg) + 1 >= ZAI_ENV_MAX_BUFSIZ) {
             return false;
         } else {
-            memcpy(buf.ptr, Z_STRVAL_P(cfg), Z_STRLEN_P(cfg) + 1);
+            memcpy(buf->ptr, Z_STRVAL_P(cfg), Z_STRLEN_P(cfg) + 1);
         }
         return true;
     }
 
     return false;
 }
 
-static bool ddtrace_conf_otel_resource_attributes_special(const char *tag, int len, zai_env_buffer buf, bool pre_rinit) {
-    if (!get_otel_value((zai_str)ZAI_STRL("OTEL_RESOURCE_ATTRIBUTES"), buf, pre_rinit)) {
+static bool ddtrace_conf_otel_resource_attributes_special(const char *tag, int len, zai_env_buffer *buf, bool pre_rinit) {
+    ZAI_ENV_BUFFER_INIT(local, ZAI_ENV_MAX_BUFSIZ);
+    if (!get_otel_value((zai_str)ZAI_STRL("OTEL_RESOURCE_ATTRIBUTES"), &local, pre_rinit)) {
         return false;
     }
 
-    for (char *cur = buf.ptr, *key_start = cur; *cur; ++cur) {
+    for (char *cur = local.ptr, *key_start = cur; *cur; ++cur) {
         if (*cur == '=') {
             char *key_end = cur++;
             while (*cur && *cur != ',') {
                 ++cur;
             }
             if (key_end - key_start == len && memcmp(key_start, tag, len) == 0 && key_end[1]) {
                 size_t vallen = cur - (key_end + 1);
-                memcpy(buf.ptr, key_end + 1, vallen);
-                buf.ptr[vallen] = 0;
+                memcpy(buf->ptr, key_end + 1, vallen);
+                buf->ptr[vallen] = 0;
                 return true;
             }
             key_start = cur-- + 1;
@@ -78,92 +79,95 @@ static bool ddtrace_conf_otel_resource_attributes_special(const char *tag, int l
     return false;
 }
 
-bool ddtrace_conf_otel_resource_attributes_env(zai_env_buffer buf, bool pre_rinit) {
+bool ddtrace_conf_otel_resource_attributes_env(zai_env_buffer *buf, bool pre_rinit) {
     return ddtrace_conf_otel_resource_attributes_special(ZEND_STRL("deployment.environment"), buf, pre_rinit);
 }
 
-bool ddtrace_conf_otel_resource_attributes_version(zai_env_buffer buf, bool pre_rinit) {
+bool ddtrace_conf_otel_resource_attributes_version(zai_env_buffer *buf, bool pre_rinit) {
     return ddtrace_conf_otel_resource_attributes_special(ZEND_STRL("service.version"), buf, pre_rinit);
 }
 
-bool ddtrace_conf_otel_service_name(zai_env_buffer buf, bool pre_rinit) {
+bool ddtrace_conf_otel_service_name(zai_env_buffer *buf, bool pre_rinit) {
     return get_otel_value((zai_str)ZAI_STRL("OTEL_SERVICE_NAME"), buf, pre_rinit)
         || ddtrace_conf_otel_resource_attributes_special(ZEND_STRL("service.name"), buf, pre_rinit);
 }
 
-bool ddtrace_conf_otel_log_level(zai_env_buffer buf, bool pre_rinit) {
+bool ddtrace_conf_otel_log_level(zai_env_buffer *buf, bool pre_rinit) {
     return get_otel_value((zai_str)ZAI_STRL("OTEL_LOG_LEVEL"), buf, pre_rinit);
 }
 
-bool ddtrace_conf_otel_propagators(zai_env_buffer buf, bool pre_rinit) {
-    if (!get_otel_value((zai_str)ZAI_STRL("OTEL_PROPAGATORS"), buf, pre_rinit)) {
+bool ddtrace_conf_otel_propagators(zai_env_buffer *buf, bool pre_rinit) {
+    ZAI_ENV_BUFFER_INIT(local, ZAI_ENV_MAX_BUFSIZ);
+    if (!get_otel_value((zai_str)ZAI_STRL("OTEL_PROPAGATORS"), &local, pre_rinit)) {
         return false;
     }
-    char *off = (char *)zend_memnstr(buf.ptr, ZEND_STRL("b3"), buf.ptr + strlen(buf.ptr));
-    if (off && (!off[strlen("b3")] || off[strlen("b3")] == ',') && strlen(buf.ptr) < buf.len - 100) {
-        memmove(off + strlen("b3 single header"), off + strlen("b3"), buf.ptr + strlen(buf.ptr) - (off + strlen("b3")) + 1);
+    memcpy(buf->ptr, local.ptr, strlen(local.ptr) + 1);
+    char *off = (char *)zend_memnstr(buf->ptr, ZEND_STRL("b3"), buf->ptr + strlen(buf->ptr));
+    if (off && (!off[strlen("b3")] || off[strlen("b3")] == ',') && strlen(buf->ptr) < buf->len - 100) {
+        memmove(off + strlen("b3 single header"), off + strlen("b3"), buf->ptr + strlen(buf->ptr) - (off + strlen("b3")) + 1);
         memcpy(off, "b3 single header", strlen("b3 single header"));
     }
     return true;
 }
 
-bool ddtrace_conf_otel_sample_rate(zai_env_buffer buf, bool pre_rinit) {
+bool ddtrace_conf_otel_sample_rate(zai_env_buffer *buf, bool pre_rinit) {
     if (!get_otel_value((zai_str)ZAI_STRL("OTEL_TRACES_SAMPLER"), buf, pre_rinit)) {
         return false;
     }
 
-    if (strcmp(buf.ptr, "always_on") == 0 || strcmp(buf.ptr, "parentbased_always_on") == 0) {
-        memcpy(buf.ptr, ZEND_STRS("1"));
+    if (strcmp(buf->ptr, "always_on") == 0 || strcmp(buf->ptr, "parentbased_always_on") == 0) {
+        buf->ptr = "1"; buf->len = 1;
         return true;
     }
-    if (strcmp(buf.ptr, "always_off") == 0 || strcmp(buf.ptr, "parentbased_always_off") == 0) {
-        memcpy(buf.ptr, ZEND_STRS("0"));
+    if (strcmp(buf->ptr, "always_off") == 0 || strcmp(buf->ptr, "parentbased_always_off") == 0) {
+        buf->ptr = "0"; buf->len = 1;
         return true;
     }
-    if (strcmp(buf.ptr, "traceidratio") == 0 || strcmp(buf.ptr, "parentbased_traceidratio") == 0) {
+    if (strcmp(buf->ptr, "traceidratio") == 0 || strcmp(buf->ptr, "parentbased_traceidratio") == 0) {
         if (get_otel_value((zai_str)ZAI_STRL("OTEL_TRACES_SAMPLER_ARG"), buf, pre_rinit)) {
             return true;
         }
-        LOG_ONCE(WARN, "OTEL_TRACES_SAMPLER is %s, but is missing OTEL_TRACES_SAMPLER_ARG", buf.ptr);
+        LOG_ONCE(WARN, "OTEL_TRACES_SAMPLER is %s, but is missing OTEL_TRACES_SAMPLER_ARG", buf->ptr);
     } else {
-        LOG_ONCE(WARN, "OTEL_TRACES_SAMPLER has invalid value: %s", buf.ptr);
+        LOG_ONCE(WARN, "OTEL_TRACES_SAMPLER has invalid value: %s", buf->ptr);
     }
     report_otel_cfg_telemetry_invalid("otel_traces_sampler", "dd_trace_sample_rate", pre_rinit);
     return false;
 }
 
-bool ddtrace_conf_otel_traces_exporter(zai_env_buffer buf, bool pre_rinit) {
+bool ddtrace_conf_otel_traces_exporter(zai_env_buffer *buf, bool pre_rinit) {
     if (get_otel_value((zai_str)ZAI_STRL("OTEL_TRACES_EXPORTER"), buf, pre_rinit)) {
-        if (strcmp(buf.ptr, "none") == 0) {
-            memcpy(buf.ptr, ZEND_STRS("0"));
+        if (strcmp(buf->ptr, "none") == 0) {
+            buf->ptr = "0"; buf->len = 1;
             return true;
         }
-        LOG_ONCE(WARN, "OTEL_TRACES_EXPORTER has invalid value: %s", buf.ptr);
+        LOG_ONCE(WARN, "OTEL_TRACES_EXPORTER has invalid value: %s", buf->ptr);
         report_otel_cfg_telemetry_invalid("otel_traces_exporter", "dd_trace_enabled", pre_rinit);
     }
     return false;
 }
 
-bool ddtrace_conf_otel_metrics_exporter(zai_env_buffer buf, bool pre_rinit) {
+bool ddtrace_conf_otel_metrics_exporter(zai_env_buffer *buf, bool pre_rinit) {
     if (get_otel_value((zai_str)ZAI_STRL("OTEL_METRICS_EXPORTER"), buf, pre_rinit)) {
-        if (strcmp(buf.ptr, "none") == 0) {
-            memcpy(buf.ptr, ZEND_STRS("0"));
+        if (strcmp(buf->ptr, "none") == 0) {
+            buf->ptr = "0"; buf->len = 1;
             return true;
         }
-        LOG_ONCE(WARN, "OTEL_METRICS_EXPORTER has invalid value: %s", buf.ptr);
+        LOG_ONCE(WARN, "OTEL_METRICS_EXPORTER has invalid value: %s", buf->ptr);
         report_otel_cfg_telemetry_invalid("otel_metrics_exporter", "dd_integration_metrics_enabled", pre_rinit);
     }
     return false;
 }
 
-bool ddtrace_conf_otel_resource_attributes_tags(zai_env_buffer buf, bool pre_rinit) {
-    if (!get_otel_value((zai_str)ZAI_STRL("OTEL_RESOURCE_ATTRIBUTES"), buf, pre_rinit)) {
+bool ddtrace_conf_otel_resource_attributes_tags(zai_env_buffer *buf, bool pre_rinit) {
+    ZAI_ENV_BUFFER_INIT(local, ZAI_ENV_MAX_BUFSIZ);
+    if (!get_otel_value((zai_str)ZAI_STRL("OTEL_RESOURCE_ATTRIBUTES"), &local, pre_rinit)) {
         return false;
     }
 
-    char *out = buf.ptr;
+    char *out = buf->ptr;
     int tags = 0;
-    for (char *cur = buf.ptr, *key_start = cur; *cur; ++cur) {
+    for (char *cur = local.ptr, *key_start = cur; *cur; ++cur) {
         if (*cur == '=') {
             char *key = key_start, *key_end = cur++;
             while (*cur && *cur != ',') {
@@ -190,7 +194,7 @@ bool ddtrace_conf_otel_resource_attributes_tags(zai_env_buffer buf, bool pre_rin
             --cur;
         }
     }
-    if (out != buf.ptr) {
+    if (out != buf->ptr) {
         --out;
     }
     *out = 0;

ext/otel_config.h

@@ -3,14 +3,14 @@
 
 #include <env/env.h>
 
-bool ddtrace_conf_otel_resource_attributes_env(zai_env_buffer buf, bool pre_rinit);
-bool ddtrace_conf_otel_resource_attributes_version(zai_env_buffer buf, bool pre_rinit);
-bool ddtrace_conf_otel_service_name(zai_env_buffer buf, bool pre_rinit);
-bool ddtrace_conf_otel_log_level(zai_env_buffer buf, bool pre_rinit);
-bool ddtrace_conf_otel_propagators(zai_env_buffer buf, bool pre_rinit);
-bool ddtrace_conf_otel_sample_rate(zai_env_buffer buf, bool pre_rinit);
-bool ddtrace_conf_otel_traces_exporter(zai_env_buffer buf, bool pre_rinit);
-bool ddtrace_conf_otel_metrics_exporter(zai_env_buffer buf, bool pre_rinit);
-bool ddtrace_conf_otel_resource_attributes_tags(zai_env_buffer buf, bool pre_rinit);
+bool ddtrace_conf_otel_resource_attributes_env(zai_env_buffer *buf, bool pre_rinit);
+bool ddtrace_conf_otel_resource_attributes_version(zai_env_buffer *buf, bool pre_rinit);
+bool ddtrace_conf_otel_service_name(zai_env_buffer *buf, bool pre_rinit);
+bool ddtrace_conf_otel_log_level(zai_env_buffer *buf, bool pre_rinit);
+bool ddtrace_conf_otel_propagators(zai_env_buffer *buf, bool pre_rinit);
+bool ddtrace_conf_otel_sample_rate(zai_env_buffer *buf, bool pre_rinit);
+bool ddtrace_conf_otel_traces_exporter(zai_env_buffer *buf, bool pre_rinit);
+bool ddtrace_conf_otel_metrics_exporter(zai_env_buffer *buf, bool pre_rinit);
+bool ddtrace_conf_otel_resource_attributes_tags(zai_env_buffer *buf, bool pre_rinit);
 
 #endif // DD_OTEL_CONFIG_H

zend_abstract_interface/config/config.c

@@ -3,6 +3,7 @@
 #include <assert.h>
 #include <json/json.h>
 #include <main/php.h>
+#include <main/SAPI.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
@@ -12,11 +13,34 @@ HashTable zai_config_name_map = {0};
 uint16_t zai_config_memoized_entries_count = 0;
 zai_config_memoized_entry zai_config_memoized_entries[ZAI_CONFIG_ENTRIES_COUNT_MAX];
 
-static bool zai_config_get_env_value(zai_str name, zai_env_buffer buf) {
-    // TODO Handle other return codes
-    // We want to explicitly allow pre-RINIT access to env vars here. So that callers can have an early view at config.
-    // But in general allmost all configurations shall only be accessed after first RINIT. (the trivial getter will
-    return zai_getenv_ex(name, buf, true) == ZAI_ENV_SUCCESS;
+// Indexed [config_id][name_index]; NULL means not set.
+static char *zai_config_cached_sys_env[ZAI_CONFIG_ENTRIES_COUNT_MAX][ZAI_CONFIG_NAMES_COUNT_MAX];
+
+const char *zai_config_sys_env_cached(zai_config_id id, uint8_t name_index) {
+    return zai_config_cached_sys_env[id][name_index];
+}
+
+static void zai_config_cache_sys_env(void) {
+    for (zai_config_id i = 0; i < zai_config_memoized_entries_count; i++) {
+        zai_config_memoized_entry *m = &zai_config_memoized_entries[i];
+        for (uint8_t n = 0; n < m->names_count; n++) {
+            zai_str name = ZAI_STR_NEW(m->names[n].ptr, m->names[n].len);
+            zai_option_str val = zai_sys_getenv(name);
+            zai_config_cached_sys_env[i][n] = zai_option_str_is_some(val)
+                ? pestrdup(val.ptr, 1) : NULL;
+        }
+    }
+}
+
+static void zai_config_clear_sys_env_cache(void) {
+    for (zai_config_id i = 0; i < zai_config_memoized_entries_count; i++) {
+        for (uint8_t n = 0; n < zai_config_memoized_entries[i].names_count; n++) {
+            if (zai_config_cached_sys_env[i][n]) {
+                pefree(zai_config_cached_sys_env[i][n], 1);
+                zai_config_cached_sys_env[i][n] = NULL;
+            }
+        }
+    }
 }
 
 static inline void zai_config_process_env(zai_config_memoized_entry *memoized, zai_env_buffer buf, zai_option_str *value) {
@@ -31,7 +55,7 @@ static inline void zai_config_process_env(zai_config_memoized_entry *memoized, z
     }
 }
 
-static void zai_config_find_and_set_value(zai_config_memoized_entry *memoized, zai_config_id id) {
+static void zai_config_find_and_set_value(zai_config_memoized_entry *memoized, zai_config_id id, bool in_request) {
     // TODO Use less buffer space
     // TODO Make a more generic zai_string_buffer
     ZAI_ENV_BUFFER_INIT(buf, ZAI_ENV_MAX_BUFSIZ);
@@ -48,18 +72,34 @@ static void zai_config_find_and_set_value(zai_config_memoized_entry *memoized, z
             name_index = ZAI_CONFIG_ORIGIN_FLEET_STABLE;
             memoized->config_id = (zai_str) ZAI_STR_FROM_ZSTR(entry->config_id);
             break;
-        } else if (zai_config_get_env_value(name, buf)) {
-            zai_config_process_env(memoized, buf, &value);
-            break;
-        } else if (entry && entry->source == DDOG_LIBRARY_CONFIG_SOURCE_LOCAL_STABLE_CONFIG) {
+        } else {
+            // SAPI env (e.g. Apache SetEnv) takes priority over the sys env
+            // cache and must be checked here at first RINIT, not only in
+            // zai_config_ini_rinit. Code that runs between first_time_rinit
+            // and zai_config_ini_rinit--such as the signal handler setup that
+            // reads DD_TRACE_HEALTH_METRICS_ENABLED--relies on SAPI-provided
+            // values being present in the decoded config.
+            if (in_request && zai_sapi_getenv(name, &buf) == ZAI_ENV_SUCCESS) {
+                zai_config_process_env(memoized, buf, &value);
+                break;
+            }
+            const char *cached = zai_config_sys_env_cached(id, name_index);
+            if (cached) {
+                buf.ptr = (char *)cached;
+                buf.len = strlen(cached);
+                zai_config_process_env(memoized, buf, &value);
+                break;
+            }
+        }
+        if (entry && entry->source == DDOG_LIBRARY_CONFIG_SOURCE_LOCAL_STABLE_CONFIG) {
             strcpy(buf.ptr, ZSTR_VAL(entry->value));
             zai_config_process_env(memoized, buf, &value);
             name_index = ZAI_CONFIG_ORIGIN_LOCAL_STABLE;
             memoized->config_id = (zai_str) ZAI_STR_FROM_ZSTR(entry->config_id);
             break;
         }
     }
-    if (!value.len && memoized->env_config_fallback && memoized->env_config_fallback(buf, true)) {
+    if (!value.len && memoized->env_config_fallback && memoized->env_config_fallback(&buf, true)) {
         zai_config_process_env(memoized, buf, &value);
         name_index = ZAI_CONFIG_ORIGIN_MODIFIED;
     }
@@ -153,6 +193,7 @@ bool zai_config_minit(zai_config_entry entries[], size_t entries_count, zai_conf
 #if PHP_VERSION_ID >= 70300 && PHP_VERSION_ID < 70400
     zai_persistent_new_interned_string = zend_new_interned_string;
 #endif
+    zai_config_cache_sys_env();
     return true;
 }
 
@@ -164,11 +205,13 @@ static void zai_config_dtor_memoized_zvals(void) {
 
 void zai_config_mshutdown(void) {
     zai_config_dtor_memoized_zvals();
+    zai_config_memoized_entries_count = 0;
     if (zai_config_name_map.nTableSize) {
         zend_hash_destroy(&zai_config_name_map);
     }
     zai_config_ini_mshutdown();
     zai_config_stable_file_mshutdown();
+    zai_config_clear_sys_env_cache();
 }
 
 void zai_config_runtime_config_ctor(void);
@@ -237,9 +280,16 @@ void zai_config_first_time_rinit(bool in_request) {
     (void)in_request;
 #endif
 
+    // Non-CLI SAPIs (CGI/FPM/mod_php) may inject env vars before the first
+    // request, so refresh the cache to pick them up.
+    if (in_request && strcmp(sapi_module.name, "cli") != 0) {
+        zai_config_clear_sys_env_cache();
+        zai_config_cache_sys_env();
+    }
+
     for (uint16_t i = 0; i < zai_config_memoized_entries_count; i++) {
         zai_config_memoized_entry *memoized = &zai_config_memoized_entries[i];
-        zai_config_find_and_set_value(memoized, i);
+        zai_config_find_and_set_value(memoized, i, in_request);
 #if PHP_VERSION_ID >= 70300
         zai_config_intern_zval(&memoized->decoded_value);
 #else

zend_abstract_interface/config/config.h

@@ -110,6 +110,9 @@ zval *zai_config_get_value(zai_config_id id);
 
 bool zai_config_get_id_by_name(zai_str name, zai_config_id *id);
 
+// Returns NULL if not set; persistent allocation, must not be freed.
+const char *zai_config_sys_env_cached(zai_config_id id, uint8_t name_index);
+
 // Adds name to name<->id mapping. Id may be present multiple times.
 void zai_config_register_config_id(zai_config_name *name, zai_config_id id);