Nginx OTel module.
This commit is contained in:
Pavel Pautov
dplotnikov-f5
parent
a0389d8296
commit
3430e85c34
8 changed files with 1042 additions and 0 deletions
452
src/http_module.cpp
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452
src/http_module.cpp
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@ -0,0 +1,452 @@
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extern "C" {
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#include <ngx_config.h>
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#include <ngx_core.h>
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#include <ngx_http.h>
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}
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#include "str_view.hpp"
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#include "trace_context.hpp"
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#include "batch_exporter.hpp"
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extern ngx_module_t gHttpModule;
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namespace {
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struct MainConf {
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ngx_str_t endpoint;
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ngx_msec_t interval;
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size_t batchSize;
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size_t batchCount;
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ngx_str_t serviceName;
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};
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struct LocationConf {
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ngx_http_complex_value_t* trace;
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};
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char* setExporter(ngx_conf_t* cf, ngx_command_t* cmd, void* conf);
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ngx_command_t gCommands[] = {
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{ ngx_string("otel_exporter"),
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NGX_HTTP_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_NOARGS,
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setExporter,
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NGX_HTTP_MAIN_CONF_OFFSET },
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{ ngx_string("otel_service_name"),
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NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1,
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ngx_conf_set_str_slot,
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NGX_HTTP_MAIN_CONF_OFFSET,
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offsetof(MainConf, serviceName) },
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{ ngx_string("otel_trace"),
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NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
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ngx_http_set_complex_value_slot,
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NGX_HTTP_LOC_CONF_OFFSET,
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offsetof(LocationConf, trace) },
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ngx_null_command
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};
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ngx_command_t gExporterCommands[] = {
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{ ngx_string("endpoint"),
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NGX_CONF_TAKE1,
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ngx_conf_set_str_slot,
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0,
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offsetof(MainConf, endpoint) },
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{ ngx_string("interval"),
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NGX_CONF_TAKE1,
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ngx_conf_set_msec_slot,
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0,
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offsetof(MainConf, interval) },
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{ ngx_string("batch_size"),
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NGX_CONF_TAKE1,
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ngx_conf_set_size_slot,
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0,
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offsetof(MainConf, batchSize) },
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{ ngx_string("batch_count"),
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NGX_CONF_TAKE1,
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ngx_conf_set_size_slot,
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0,
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offsetof(MainConf, batchCount) },
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ngx_null_command
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};
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std::unique_ptr<BatchExporter> gExporter;
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StrView toStrView(ngx_str_t str)
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{
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return StrView((char*)str.data, str.len);
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}
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ngx_int_t onRequestStart(ngx_http_request_t* r)
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{
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// don't let internal redirects to override sampling decision
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if (r->internal) {
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return NGX_DECLINED;
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}
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bool sampled = false;
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auto lcf = (LocationConf*)ngx_http_get_module_loc_conf(r, gHttpModule);
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if (lcf->trace != NULL) {
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ngx_str_t trace;
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if (ngx_http_complex_value(r, lcf->trace, &trace) != NGX_OK) {
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return NGX_ERROR;
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}
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sampled = toStrView(trace) == "on";
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}
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if (sampled) {
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ngx_http_set_ctx(r, &gHttpModule, gHttpModule);
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}
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return NGX_DECLINED;
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}
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StrView getServerName(ngx_http_request_t* r)
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{
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auto cscf = (ngx_http_core_srv_conf_t*)
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ngx_http_get_module_srv_conf(r, ngx_http_core_module);
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auto name = cscf->server_name;
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if (name.len == 0) {
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name = r->headers_in.server;
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}
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return toStrView(name);
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}
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void addDefaultAttrs(BatchExporter::Span& span, ngx_http_request_t* r)
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{
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// based on trace semantic conventions for HTTP from 1.16.0 OTel spec
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span.add("http.method", toStrView(r->method_name));
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span.add("http.target", toStrView(r->unparsed_uri));
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auto clcf = (ngx_http_core_loc_conf_t*)
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ngx_http_get_module_loc_conf(r, ngx_http_core_module);
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if (clcf->name.len) {
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span.add("http.route", toStrView(clcf->name));
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}
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span.add("http.scheme", r->connection->ssl ? "https" : "http");
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auto protocol = toStrView(r->http_protocol);
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if (protocol.size() > 5) { // "HTTP/"
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span.add("http.flavor", protocol.substr(5));
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}
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if (r->headers_in.user_agent) {
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span.add("http.user_agent", toStrView(r->headers_in.user_agent->value));
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}
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auto received = r->headers_in.content_length_n;
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span.add("http.request_content_length", received > 0 ? received : 0);
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auto sent = r->connection->sent - (off_t)r->header_size;
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span.add("http.response_content_length", sent > 0 ? sent : 0);
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auto status = r->err_status ? r->err_status : r->headers_out.status;
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if (status) {
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span.add("http.status_code", status);
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if (status >= 500) {
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span.setError();
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}
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}
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span.add("net.host.name", getServerName(r));
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if (ngx_connection_local_sockaddr(r->connection, NULL, 0) == NGX_OK) {
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auto port = ngx_inet_get_port(r->connection->local_sockaddr);
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auto defaultPort = r->connection->ssl ? 443 : 80;
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if (port != defaultPort) {
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span.add("net.host.port", port);
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}
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}
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span.add("net.sock.peer.addr", toStrView(r->connection->addr_text));
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span.add("net.sock.peer.port", ngx_inet_get_port(r->connection->sockaddr));
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}
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ngx_int_t onRequestEnd(ngx_http_request_t* r)
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{
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if (!ngx_http_get_module_ctx(r, gHttpModule)) {
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return NGX_DECLINED;
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}
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auto clcf = (ngx_http_core_loc_conf_t*)ngx_http_get_module_loc_conf(
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r, ngx_http_core_module);
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auto now = ngx_timeofday();
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auto toNanoSec = [](time_t sec, ngx_msec_t msec) -> uint64_t {
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return (sec * 1000 + msec) * 1000000;
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};
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try {
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BatchExporter::SpanInfo info{
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toStrView(clcf->name), TraceContext::generate(true), {},
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toNanoSec(r->start_sec, r->start_msec),
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toNanoSec(now->sec, now->msec)};
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bool ok = gExporter->add(info, [r](BatchExporter::Span& span) {
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addDefaultAttrs(span, r);
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});
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if (!ok) {
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static size_t dropped = 0;
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static time_t lastLog = 0;
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++dropped;
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if (lastLog != ngx_time()) {
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lastLog = ngx_time();
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ngx_log_error(NGX_LOG_NOTICE, r->connection->log, 0,
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"OTel dropped records: %uz", dropped);
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}
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}
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} catch (const std::exception& e) {
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ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
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"OTel failed to add span: %s", e.what());
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return NGX_ERROR;
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}
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return NGX_DECLINED;
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}
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ngx_int_t initModule(ngx_conf_t* cf)
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{
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auto cmcf = (ngx_http_core_main_conf_t*)ngx_http_conf_get_module_main_conf(
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cf, ngx_http_core_module);
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auto h = (ngx_http_handler_pt*)ngx_array_push(
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&cmcf->phases[NGX_HTTP_REWRITE_PHASE].handlers);
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if (h == NULL) {
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return NGX_ERROR;
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}
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*h = onRequestStart;
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h = (ngx_http_handler_pt*)ngx_array_push(
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&cmcf->phases[NGX_HTTP_LOG_PHASE].handlers);
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if (h == NULL) {
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return NGX_ERROR;
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}
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*h = onRequestEnd;
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return NGX_OK;
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}
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ngx_int_t initWorkerProcess(ngx_cycle_t* cycle)
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{
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auto mcf = (MainConf*)ngx_http_cycle_get_module_main_conf(
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cycle, gHttpModule);
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try {
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gExporter.reset(new BatchExporter(
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toStrView(mcf->endpoint),
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mcf->batchSize,
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mcf->batchCount,
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toStrView(mcf->serviceName)));
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} catch (const std::exception& e) {
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ngx_log_error(NGX_LOG_CRIT, cycle->log, 0,
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"OTel worker init error: %s", e.what());
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return NGX_ERROR;
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}
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static ngx_connection_t dummy;
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static ngx_event_t flushEvent;
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flushEvent.data = &dummy;
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flushEvent.log = cycle->log;
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flushEvent.cancelable = 1;
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flushEvent.handler = [](ngx_event_t* ev) {
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try {
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gExporter->flush();
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} catch (const std::exception& e) {
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ngx_log_error(NGX_LOG_CRIT, ev->log, 0,
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"OTel flush error: %s", e.what());
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}
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auto mcf = (MainConf*)ngx_http_cycle_get_module_main_conf(
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ngx_cycle, gHttpModule);
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ngx_add_timer(ev, mcf->interval);
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};
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ngx_add_timer(&flushEvent, mcf->interval);
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return NGX_OK;
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}
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void exitWorkerProcess(ngx_cycle_t* cycle)
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{
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try {
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gExporter->flush();
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} catch (const std::exception& e) {
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ngx_log_error(NGX_LOG_CRIT, cycle->log, 0,
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"OTel flush error: %s", e.what());
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}
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gExporter.reset();
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}
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char* setExporter(ngx_conf_t* cf, ngx_command_t* cmd, void* conf)
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{
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auto mcf = (MainConf*)conf;
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if (mcf->endpoint.len) {
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return (char*)"is duplicate";
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}
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auto cfCopy = *cf;
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cfCopy.handler = [](ngx_conf_t* cf, ngx_command_t*, void*) {
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auto name = (ngx_str_t*)cf->args->elts;
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for (auto cmd = gExporterCommands; cmd->name.len; cmd++) {
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if (ngx_strcmp(name->data, cmd->name.data) != 0) {
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continue;
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}
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if (cf->args->nelts != 2) {
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ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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"invalid number of arguments in \"%V\" "
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"directive of \"otel_exporter\"", name);
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return (char*)NGX_CONF_ERROR;
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}
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auto rv = cmd->set(cf, cmd, cf->handler_conf);
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if (rv == NGX_CONF_OK) {
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return rv;
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}
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if (rv != NGX_CONF_ERROR) {
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ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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"\"%V\" directive of \"otel_exporter\" %s", name, rv);
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}
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return (char*)NGX_CONF_ERROR;
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}
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ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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"unknown directive \"%V\" in \"otel_exporter\"", name);
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return (char*)NGX_CONF_ERROR;
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};
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cfCopy.handler_conf = mcf;
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auto rv = ngx_conf_parse(&cfCopy, NULL);
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if (rv != NGX_CONF_OK) {
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return rv;
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}
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if (mcf->endpoint.len == 0) {
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ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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"\"otel_exporter\" requires \"endpoint\"");
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return (char*)NGX_CONF_ERROR;
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}
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return NGX_CONF_OK;
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}
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void* createMainConf(ngx_conf_t* cf)
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{
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auto mcf = (MainConf*)ngx_pcalloc(cf->pool, sizeof(MainConf));
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if (mcf == NULL) {
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return NULL;
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}
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mcf->interval = NGX_CONF_UNSET_MSEC;
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mcf->batchSize = NGX_CONF_UNSET_SIZE;
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mcf->batchCount = NGX_CONF_UNSET_SIZE;
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return mcf;
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}
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char* initMainConf(ngx_conf_t* cf, void* conf)
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{
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auto mcf = (MainConf*)conf;
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if (mcf->endpoint.len == 0) {
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ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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"\"otel_exporter\" block is missing");
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return (char*)NGX_CONF_ERROR;
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}
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ngx_conf_init_msec_value(mcf->interval, 5000);
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ngx_conf_init_size_value(mcf->batchSize, 512);
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ngx_conf_init_size_value(mcf->batchCount, 4);
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if (mcf->serviceName.data == NULL) {
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mcf->serviceName = ngx_string("unknown_service:nginx");
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}
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return NGX_CONF_OK;
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}
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void* createLocationConf(ngx_conf_t* cf)
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{
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auto conf = (LocationConf*)ngx_pcalloc(cf->pool, sizeof(LocationConf));
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if (conf == NULL) {
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return NULL;
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}
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conf->trace = (ngx_http_complex_value_t*)NGX_CONF_UNSET_PTR;
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return conf;
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}
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char* mergeLocationConf(ngx_conf_t* cf, void* parent, void* child)
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{
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auto prev = (LocationConf*)parent;
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auto conf = (LocationConf*)child;
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ngx_conf_merge_ptr_value(conf->trace, prev->trace, NULL);
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return NGX_CONF_OK;
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}
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ngx_http_module_t gHttpModuleCtx = {
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NULL, /* preconfiguration */
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initModule, /* postconfiguration */
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createMainConf, /* create main configuration */
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initMainConf, /* init main configuration */
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NULL, /* create server configuration */
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NULL, /* merge server configuration */
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createLocationConf, /* create location configuration */
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mergeLocationConf /* merge location configuration */
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};
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}
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ngx_module_t gHttpModule = {
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NGX_MODULE_V1,
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&gHttpModuleCtx, /* module context */
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gCommands, /* module directives */
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NGX_HTTP_MODULE, /* module type */
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NULL, /* init master */
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NULL, /* init module */
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initWorkerProcess, /* init process */
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NULL, /* init thread */
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NULL, /* exit thread */
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exitWorkerProcess, /* exit process */
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NULL, /* exit master */
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NGX_MODULE_V1_PADDING
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};
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