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Add labels to metrics #3

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Merged
proffalken merged 2 commits into from
Jul 30, 2025
Merged

Add labels to metrics #3

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2fbc8a3
Add labels to metrics
proffalken Jul 30, 2025
8ab0867
Histograms and Counters now work!
proffalken Jul 30, 2025
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128 changes: 101 additions & 27 deletions include/OtelMetrics.h
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Original file line number Diff line number Diff line change
Expand Up @@ -7,52 +7,99 @@

namespace OTel {

// — a single, shared ResourceConfig for all metrics —
static inline OTelResourceConfig& defaultMetricResource() {
static OTelResourceConfig rc;
return rc; // <-- returns a reference, not a temporary
}

struct Metrics {
/// Call once in setup() to stamp service attributes on all metrics
static void begin(const String& serviceName,
const String& serviceNamespace,
const String& instanceId,
const String& version = "") {
auto& rc = defaultMetricResource();
rc.setAttribute("service.name", serviceName);
rc.setAttribute("service.namespace", serviceNamespace);
rc.setAttribute("service.instance.id", instanceId);
if (!version.isEmpty()) {
rc.setAttribute("service.version", version);
}
}
};

class OTelMetricBase {
protected:
String name;
String unit;
OTelResourceConfig config;
OTelResourceConfig& config = OTel::defaultMetricResource();
//OTelResourceConfig config;

public:
OTelMetricBase(String metricName, String metricUnit = "")
: name(metricName), unit(metricUnit), config(getDefaultResource()) {}

void setAttribute(const String &key, const String &value) {
config.setAttribute(key, value);
}
// ctor must initialize config from the ref‑returning function
OTelMetricBase(const String& metricName,
const String& metricUnit)
: name(metricName),
unit(metricUnit),
config(OTel::defaultMetricResource()) // <-- now an lvalue reference
{}
};

#include <ArduinoJson.h>
#include "OtelDefaults.h" // provides OTelResourceConfig
#include "OtelSender.h" // provides OTelSender::sendJson()

class OTelGauge : public OTelMetricBase {
public:
using OTelMetricBase::OTelMetricBase;

void set(float value) {
// elastic, heap‑backed document—no need to pick static vs dynamic.
JsonDocument doc;

JsonObject resourceMetric = doc["resourceMetrics"].add<JsonObject>();
// ── resourceMetrics → [ { … } ]
JsonArray resourceMetrics = doc["resourceMetrics"].to<JsonArray>();
JsonObject resourceMetric = resourceMetrics.add<JsonObject>();

// └─ resource
JsonObject resource = resourceMetric["resource"].to<JsonObject>();
config.addResourceAttributes(resource);

JsonObject scopeMetric = resourceMetric["scopeMetrics"].add<JsonObject>();
// ── scopeMetrics → [ { … } ]
JsonArray scopeMetrics = resourceMetric["scopeMetrics"].to<JsonArray>();
JsonObject scopeMetric = scopeMetrics.add<JsonObject>();

// └─ scope
JsonObject scope = scopeMetric["scope"].to<JsonObject>();
scope["name"] = "otel-embedded";
scope["name"] = "otel-embedded";
scope["version"] = "0.1.0";

JsonObject metric = scopeMetric["metrics"].add<JsonObject>();
// └─ metrics → [ { … } ]
JsonArray metrics = scopeMetric["metrics"].to<JsonArray>();
JsonObject metric = metrics.add<JsonObject>();
metric["name"] = name;
metric["unit"] = unit;
metric["type"] = "gauge";

JsonObject gauge = metric["gauge"].to<JsonObject>();
JsonObject dp = gauge["dataPoints"].add<JsonObject>();
// └─ gauge.dataPoints → [ { … } ]
JsonObject gauge = metric["gauge"].to<JsonObject>();
JsonArray dataPoints = gauge["dataPoints"].to<JsonArray>();
JsonObject dp = dataPoints.add<JsonObject>();

// ├─ attach the same resource labels on each point
config.addResourceAttributes(dp);

// ├─ timestamp & value
dp["timeUnixNano"] = nowUnixNano();
dp["asDouble"] = value;
dp["asDouble"] = value;

// send it off
OTelSender::sendJson("/v1/metrics", doc);
}
};


class OTelCounter : public OTelMetricBase {
private:
float count = 0;
Expand Down Expand Up @@ -97,51 +144,78 @@ class OTelHistogram : public OTelMetricBase {
using OTelMetricBase::OTelMetricBase;

void record(double value) {
// no size parameters, use the new JsonDocument
// 1) Build the top‐level JSON document
JsonDocument doc;

// resourceMetrics → array
// ── resourceMetrics → [ { … } ]
JsonArray resourceMetrics = doc["resourceMetrics"].to<JsonArray>();
JsonObject resourceMetric = resourceMetrics.add<JsonObject>();

// resource + attributes
// └─ resource
JsonObject resource = resourceMetric["resource"].to<JsonObject>();
config.addResourceAttributes(resource);

// scopeMetrics → array
// ── scopeMetrics → [ { … } ]
JsonArray scopeMetrics = resourceMetric["scopeMetrics"].to<JsonArray>();
JsonObject scopeMetric = scopeMetrics.add<JsonObject>();

// scope
// └─ scope
JsonObject scope = scopeMetric["scope"].to<JsonObject>();
scope["name"] = "otel-embedded";
scope["version"] = "0.1.0";

// metrics → array
// └─ metrics → [ { … } ]
JsonArray metrics = scopeMetric["metrics"].to<JsonArray>();
JsonObject metric = metrics.add<JsonObject>();
metric["name"] = name;
metric["unit"] = unit;
metric["type"] = "histogram";

// histogram object
// └─ histogram
JsonObject histogram = metric["histogram"].to<JsonObject>();
histogram["aggregationTemporality"] = 2;
histogram["aggregationTemporality"] = 2; // DELTA = 2

// dataPoints → array
// └─ dataPoints → [ { … } ]
JsonArray dataPoints = histogram["dataPoints"].to<JsonArray>();
JsonObject dp = dataPoints.add<JsonObject>();

// attach resource attrs, timestamp, and value
// ├─ shared resource labels
config.addResourceAttributes(dp);
dp["timeUnixNano"] = nowUnixNano();
dp["asDouble"] = value;

// ship it off
// ├─ timestamp, count, sum
dp["timeUnixNano"] = nowUnixNano();
dp["count"] = 1;
dp["sum"] = value;

// ├─ explicitBounds (define your buckets here)
static const double explicitBounds[] = {100.0, 200.0, 500.0, 1000.0};
static const size_t B = sizeof(explicitBounds) / sizeof(*explicitBounds);
JsonArray boundsArr = dp["explicitBounds"].to<JsonArray>();
for (size_t i = 0; i < B; ++i) {
boundsArr.add(explicitBounds[i]);
}

// └─ bucketCounts (one slot per boundary + underflow/overflow)
JsonArray countsArr = dp["bucketCounts"].to<JsonArray>();
// find which bucket this value falls into
size_t bucketIdx = B; // overflow by default
for (size_t i = 0; i < B; ++i) {
if (value <= explicitBounds[i]) {
bucketIdx = i;
break;
}
}
// emit counts: exactly one '1' in the right bucket, zero elsewhere
for (size_t i = 0; i <= B; ++i) {
countsArr.add(i == bucketIdx ? 1 : 0);
}

// 2) Send it
OTelSender::sendJson("/v1/metrics", doc);
}
};


} // namespace OTel

#endif
Expand Down