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Support custom resource attributes (fix #32).
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Now attributes can be set with "otel_resource_attr" directive, e.g.
    otel_resource_attr my.name "my value";
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@p-pautov
p-pautov committed Nov 13, 2024
1 parent 1074d02 commit b5c8cd8
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Showing 2 changed files with 79 additions and 25 deletions.
11 changes: 7 additions & 4 deletions src/batch_exporter.hpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -112,17 +112,20 @@ class BatchExporter {
};

BatchExporter(StrView target,
size_t batchSize, size_t batchCount, StrView serviceName) :
size_t batchSize, size_t batchCount,
const std::map<StrView, StrView>& resourceAttrs) :
batchSize(batchSize), client(std::string(target))
{
free.reserve(batchCount);
while (batchCount-- > 0) {
free.emplace_back();
auto resourceSpans = free.back().add_resource_spans();

auto attr = resourceSpans->mutable_resource()->add_attributes();
attr->set_key("service.name");
attr->mutable_value()->set_string_value(std::string(serviceName));
for (auto& attr : resourceAttrs) {
auto kv = resourceSpans->mutable_resource()->add_attributes();
kv->set_key(std::string(attr.first));
kv->mutable_value()->set_string_value(std::string(attr.second));
}

auto scopeSpans = resourceSpans->add_scope_spans();
scopeSpans->mutable_scope()->set_name("nginx");
Expand Down
93 changes: 72 additions & 21 deletions src/http_module.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@ struct OtelCtx {
TraceContext current;
};

struct MainConf {
struct MainConfBase {
ngx_str_t endpoint;
ngx_msec_t interval;
size_t batchSize;
Expand All @@ -24,6 +24,10 @@ struct MainConf {
ngx_str_t serviceName;
};

struct MainConf : MainConfBase {
std::map<StrView, StrView> resourceAttrs;
};

struct SpanAttr {
ngx_str_t name;
ngx_http_complex_value_t value;
Expand All @@ -38,6 +42,7 @@ struct LocationConf {
};

char* setExporter(ngx_conf_t* cf, ngx_command_t* cmd, void* conf);
char* addResourceAttr(ngx_conf_t* cf, ngx_command_t* cmd, void* conf);
char* addSpanAttr(ngx_conf_t* cf, ngx_command_t* cmd, void* conf);

namespace Propagation {
Expand All @@ -59,14 +64,17 @@ ngx_command_t gCommands[] = {

{ ngx_string("otel_exporter"),
NGX_HTTP_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_NOARGS,
setExporter,
NGX_HTTP_MAIN_CONF_OFFSET },
setExporter },

{ ngx_string("otel_resource_attr"),
NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE2,
addResourceAttr },

{ ngx_string("otel_service_name"),
NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1,
ngx_conf_set_str_slot,
NGX_HTTP_MAIN_CONF_OFFSET,
offsetof(MainConf, serviceName) },
offsetof(MainConfBase, serviceName) },

{ ngx_string("otel_trace"),
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
Expand Down Expand Up @@ -101,25 +109,25 @@ ngx_command_t gExporterCommands[] = {
NGX_CONF_TAKE1,
ngx_conf_set_str_slot,
0,
offsetof(MainConf, endpoint) },
offsetof(MainConfBase, endpoint) },

{ ngx_string("interval"),
NGX_CONF_TAKE1,
ngx_conf_set_msec_slot,
0,
offsetof(MainConf, interval) },
offsetof(MainConfBase, interval) },

{ ngx_string("batch_size"),
NGX_CONF_TAKE1,
ngx_conf_set_size_slot,
0,
offsetof(MainConf, batchSize) },
offsetof(MainConfBase, batchSize) },

{ ngx_string("batch_count"),
NGX_CONF_TAKE1,
ngx_conf_set_size_slot,
0,
offsetof(MainConf, batchCount) },
offsetof(MainConfBase, batchCount) },

ngx_null_command
};
Expand All @@ -136,6 +144,18 @@ ngx_str_t toNgxStr(StrView str)
return ngx_str_t{str.size(), (u_char*)str.data()};
}

MainConf* getMainConf(ngx_conf_t* cf)
{
return static_cast<MainConf*>(
(MainConfBase*)ngx_http_conf_get_module_main_conf(cf, gHttpModule));
}

MainConf* getMainConf(ngx_cycle_t* cycle)
{
return static_cast<MainConf*>(
(MainConfBase*)ngx_http_cycle_get_module_main_conf(cycle, gHttpModule));
}

LocationConf* getLocationConf(ngx_http_request_t* r)
{
return (LocationConf*)ngx_http_get_module_loc_conf(r, gHttpModule);
Expand Down Expand Up @@ -527,8 +547,7 @@ ngx_int_t initModule(ngx_conf_t* cf)

ngx_int_t initWorkerProcess(ngx_cycle_t* cycle)
{
auto mcf = (MainConf*)ngx_http_cycle_get_module_main_conf(
cycle, gHttpModule);
auto mcf = getMainConf(cycle);

// no 'http' or 'otel_exporter' blocks
if (mcf == NULL || mcf->endpoint.len == 0) {
Expand All @@ -540,7 +559,7 @@ ngx_int_t initWorkerProcess(ngx_cycle_t* cycle)
toStrView(mcf->endpoint),
mcf->batchSize,
mcf->batchCount,
toStrView(mcf->serviceName)));
mcf->resourceAttrs));
} catch (const std::exception& e) {
ngx_log_error(NGX_LOG_CRIT, cycle->log, 0,
"OTel worker init error: %s", e.what());
Expand All @@ -561,8 +580,7 @@ ngx_int_t initWorkerProcess(ngx_cycle_t* cycle)
"OTel flush error: %s", e.what());
}

auto mcf = (MainConf*)ngx_http_cycle_get_module_main_conf(
ngx_cycle, gHttpModule);
auto mcf = getMainConf((ngx_cycle_t*)ngx_cycle);

ngx_add_timer(ev, mcf->interval);
};
Expand Down Expand Up @@ -590,7 +608,7 @@ void exitWorkerProcess(ngx_cycle_t* cycle)

char* setExporter(ngx_conf_t* cf, ngx_command_t* cmd, void* conf)
{
auto mcf = (MainConf*)conf;
auto mcf = getMainConf(cf);

if (mcf->endpoint.len) {
return (char*)"is duplicate";
Expand Down Expand Up @@ -649,31 +667,64 @@ char* setExporter(ngx_conf_t* cf, ngx_command_t* cmd, void* conf)
return NGX_CONF_OK;
}

char* addResourceAttr(ngx_conf_t* cf, ngx_command_t* cmd, void* conf)
{
auto mcf = getMainConf(cf);

try {
auto args = (ngx_str_t*)cf->args->elts;
mcf->resourceAttrs[toStrView(args[1])] = toStrView(args[2]);
} catch (const std::exception& e) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "OTel: %s", e.what());
return (char*)NGX_CONF_ERROR;
}

return NGX_CONF_OK;
}

void* createMainConf(ngx_conf_t* cf)
{
auto mcf = (MainConf*)ngx_pcalloc(cf->pool, sizeof(MainConf));
if (mcf == NULL) {
auto cln = ngx_pool_cleanup_add(cf->pool, sizeof(MainConf));
if (cln == NULL) {
return NULL;
}

MainConf* mcf;
try {
mcf = new (cln->data) MainConf{};
} catch (const std::exception& e) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "OTel: %s", e.what());
return NULL;
}

cln->handler = [](void* data) {
((MainConf*)data)->~MainConf();
};

mcf->interval = NGX_CONF_UNSET_MSEC;
mcf->batchSize = NGX_CONF_UNSET_SIZE;
mcf->batchCount = NGX_CONF_UNSET_SIZE;

return mcf;
return static_cast<MainConfBase*>(mcf);
}

char* initMainConf(ngx_conf_t* cf, void* conf)
{
auto mcf = (MainConf*)conf;


ngx_conf_init_msec_value(mcf->interval, 5000);
ngx_conf_init_size_value(mcf->batchSize, 512);
ngx_conf_init_size_value(mcf->batchCount, 4);

if (mcf->serviceName.data == NULL) {
mcf->serviceName = ngx_string("unknown_service:nginx");
try {
if (mcf->serviceName.data == NULL) {
mcf->resourceAttrs.emplace("service.name", "unknown_service:nginx");
} else {
mcf->resourceAttrs["service.name"] = toStrView(mcf->serviceName);
}
} catch (const std::exception& e) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "OTel: %s", e.what());
return (char*)NGX_CONF_ERROR;
}

return NGX_CONF_OK;
Expand Down Expand Up @@ -811,7 +862,7 @@ char* mergeLocationConf(ngx_conf_t* cf, void* parent, void* child)
conf->spanAttrs = prev->spanAttrs;
}

auto mcf = (MainConf*)ngx_http_conf_get_module_main_conf(cf, gHttpModule);
auto mcf = getMainConf(cf);

if (mcf->endpoint.len == 0 && conf->trace) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
Expand Down

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