esp_opentelemetry_sdk

ESP wrapper for SDK of OpenTelemetry C++ Client.

What is OpenTelemetry?

OpenTelemetry is a collection of APIs, SDKs, and tools. Use it to instrument, generate, collect, and export telemetry data (metrics, logs, and traces) to help you analyze your software’s performance and behavior.

How to use

idf.py add-dependency albkharisov/esp_opentelemetry_sdk && \
idf.py add-dependency albkharisov/esp_opentelemetry_api

If you go another way and clone git-repo - don't forget to fetch submodules.

Description

This part provides an SDK for defining your exporters to send collected data. Data is collected via API-part OpenTelemetry data.

Operation specifics

Code inside can spawn new threads as it uses libstdc++, and ESP-IDF supports pthread. But not much: 1-2 depending on what you use. Also code uses thread_local storages so it can affect stack size of all threads. If you have tight byte-to-byte stack size keep this in mind.

Size consumption

Approximate flash consumption for example-like instrumented code (1 log/span/metric API + ostream exporters) will take:

• Compiled for debug(-Og) + exceptions takes ~560 KB
• Compiled for size (-Os) + exceptions takes ~340 KB
• Compiled for size (-Os) + no exceptions takes ~250 KB

Of course this should be considered a minimum size, as it will increase as you instrument your code.

Examples

Initializing metrics ostream exporter:

#include "opentelemetry/sdk/metrics/export/periodic_exporting_metric_reader.h"
#include "opentelemetry/sdk/metrics/meter_provider.h"
#include "opentelemetry/sdk/metrics/metric_reader.h"
#include "opentelemetry/sdk/metrics/push_metric_exporter.h"
#include "opentelemetry/exporters/ostream/metric_exporter.h"
#include "opentelemetry/metrics/meter_provider.h"
#include "opentelemetry/metrics/provider.h"


namespace metrics_api = opentelemetry::metrics;
namespace metric_sdk = opentelemetry::sdk::metrics;


void initMetric() {
    auto options = metric_sdk::PeriodicExportingMetricReaderOptions{
        .export_interval_millis = std::chrono::milliseconds(20000),
        .export_timeout_millis = std::chrono::milliseconds(10000),
    };

    std::unique_ptr<metric_sdk::PushMetricExporter> exporter{
        new opentelemetry::exporter::metrics::OStreamMetricExporter};
    std::unique_ptr<metric_sdk::MetricReader> reader{
        new metric_sdk::PeriodicExportingMetricReader(std::move(exporter), options)};

    auto provider = std::shared_ptr<metrics_api::MeterProvider>(new metric_sdk::MeterProvider());
    auto p = std::static_pointer_cast<metric_sdk::MeterProvider>(provider);
    p->AddMetricReader(std::move(reader));

    std::shared_ptr<opentelemetry::metrics::MeterProvider> api_provider(std::move(provider));
    metrics_api::Provider::SetMeterProvider(api_provider);
}

Initializing logs + traces ostream exporters:

#include "opentelemetry/exporters/ostream/log_record_exporter.h"
#include "opentelemetry/logs/logger_provider.h"
#include "opentelemetry/logs/provider.h"
#include "opentelemetry/sdk/logs/exporter.h"
#include "opentelemetry/sdk/logs/logger_provider.h"
#include "opentelemetry/sdk/logs/logger_provider_factory.h"
#include "opentelemetry/sdk/logs/simple_log_record_processor_factory.h"

#include "opentelemetry/exporters/ostream/span_exporter_factory.h"
#include "opentelemetry/sdk/trace/simple_processor_factory.h"
#include "opentelemetry/sdk/trace/tracer_provider.h"
#include "opentelemetry/sdk/trace/tracer_provider_factory.h"
#include "opentelemetry/trace/provider.h"
#include "opentelemetry/trace/tracer_provider.h"

namespace logs_api = opentelemetry::logs;
namespace logs_sdk = opentelemetry::sdk::logs;
namespace logs_exporter = opentelemetry::exporter::logs;

namespace trace_api = opentelemetry::trace;
namespace trace_sdk = opentelemetry::sdk::trace;
namespace trace_exporter = opentelemetry::exporter::trace;

void initTracer() {
    // Create ostream span exporter instance
    auto exporter = trace_exporter::OStreamSpanExporterFactory::Create();
    auto processor = trace_sdk::SimpleSpanProcessorFactory::Create(std::move(exporter));

    std::shared_ptr<opentelemetry::sdk::trace::TracerProvider> sdk_provider =
        trace_sdk::TracerProviderFactory::Create(std::move(processor));

    // Set the global trace provider
    const std::shared_ptr<trace_api::TracerProvider> &api_provider = sdk_provider;
    trace_api::Provider::SetTracerProvider(api_provider);
}

void initLogger() {
    // Create ostream log exporter instance
    auto exporter =
        std::unique_ptr<logs_sdk::LogRecordExporter>(new logs_exporter::OStreamLogRecordExporter);
    auto processor = logs_sdk::SimpleLogRecordProcessorFactory::Create(std::move(exporter));

    std::shared_ptr<opentelemetry::sdk::logs::LoggerProvider> sdk_provider(
        logs_sdk::LoggerProviderFactory::Create(std::move(processor)));

    // Set the global logger provider
    const std::shared_ptr<logs_api::LoggerProvider> &api_provider = sdk_provider;
    logs_api::Provider::SetLoggerProvider(api_provider);
}

Full original examples are here.