Bug/blocking calls

README.md

@@ -16,6 +16,12 @@ All examples assume use of the Arduino framework under PlatformIO, and that you
 
 The example code shows how to do this with the `time` library and NTP.
 
+### Concurrency and performance
+
+Where supported (RP2040 and *some* ESP32 boards), the code to process and send the data is moved to the second core of the device.
+
+This removes any blocking code and ensures that the HTTP POST call does not interfere with the main loop.
+
 ---
 
 ## 🚀 Installation with PlatformIO
@@ -173,15 +179,18 @@ Override defaults in `OtelDefaults.h` or via `-D` flags:
 | ------------------------ | ------------------ | ----------------------------------------------- |
 | `WIFI_SSID`              | `"default"`        | Wi‑Fi SSID                                      |
 | `WIFI_PASS`              | `"default"`        | Wi‑Fi password                                  |
-| `OTEL_COLLECTOR_HOST`    | `"http://…:4318"`  | OTLP HTTP endpoint                              |
-| `OTEL_COLLECTOR_PORT`    | `4318`             | OTLP HTTP port                                  |
+| `OTEL_COLLECTOR_BASE_URL`| `Null`             | The base URL (http://192.168.8.10:4318) of the otel collector |
 | `OTEL_SERVICE_NAME`      | `"demo_service"`   | Name of your service                            |
 | `OTEL_SERVICE_NAMESPACE` | `"demo_namespace"` | Service namespace                               |
 | `OTEL_SERVICE_VERSION`   | `"v1.0.0"`         | Semantic version                                |
 | `OTEL_SERVICE_INSTANCE`  | `"instance-1"`     | Unique instance ID                              |
 | `OTEL_DEPLOY_ENV`        | `"dev"`            | Deployment environment (e.g. `prod`, `staging`) |
+| `OTEL_WORKER_BURST`      | `16`               | The number of telemetry messages to process at a time |
+| `OTEL_WORKER_SLEEP_MS`   | `0`                | How long to sleep between processing messages (0 is instant) |
+| `OTEL_QUEUE_CAPACITY`    | `128`              | The maximum number of telemetry messages we can store before we start to drop data |
 | `DEBUG`                  | `Null`             | Print verbose messages including OTEL Payload to the serial port       |
 
+
 ---
 
 ## 🤝 Contributing

include/OtelSender.h

@@ -1,20 +1,77 @@
-#ifndef OTEL_SENDER_H
-#define OTEL_SENDER_H
-
+#pragma once
+#include <Arduino.h>
 #include <ArduinoJson.h>
+#include <atomic>
+
+// Optional compile-time on/off switch for all network sends.
+// You can set -DOTEL_SEND_ENABLE=0 in platformio.ini for latency tests.
+#ifndef OTEL_SEND_ENABLE
+#define OTEL_SEND_ENABLE 1
+#endif
+
+#ifndef OTEL_WORKER_BURST
+#define OTEL_WORKER_BURST 8
+#endif
+
+#ifndef OTEL_WORKER_SLEEP_MS
+#define OTEL_WORKER_SLEEP_MS 0
+#endif
+
+#ifndef OTEL_QUEUE_CAPACITY
+#define OTEL_QUEUE_CAPACITY 128
+#endif
+// Base URL of your OTLP/HTTP collector (no trailing slash), e.g. "http://192.168.8.50:4318"
+// You can override this via build_flags: -DOTEL_COLLECTOR_BASE_URL="\"http://…:4318\""
+#ifndef OTEL_COLLECTOR_BASE_URL
+#define OTEL_COLLECTOR_BASE_URL "http://192.168.8.50:4318"
+#endif
 
-#ifndef OTEL_COLLECTOR_HOST
-#define OTEL_COLLECTOR_HOST "http://192.168.8.10:4318"
+// Internal queue capacity for async sender on RP2040.
+// Keep small to bound RAM; increase if you see drops.
+#ifndef OTEL_QUEUE_CAPACITY
+#define OTEL_QUEUE_CAPACITY 16
 #endif
 
-namespace OTel {
+struct OTelQueuedItem {
+  const char* path;   // "/v1/logs", "/v1/traces", "/v1/metrics"
+  String payload;     // serialized JSON
+};
 
 class OTelSender {
 public:
+  // Main API: called by logger/tracer/metrics to send serialized JSON to OTLP/HTTP
   static void sendJson(const char* path, JsonDocument& doc);
-};
 
-} // namespace OTel
+  // Start the RP2040 core-1 worker (no-op on non-RP2040). Call once after Wi-Fi is ready.
+  static void beginAsyncWorker();
+
+  // Diagnostics (published via your health metrics if you like)
+  static uint32_t droppedCount();   // number of items dropped due to full queue
+  static bool     queueIsHealthy(); // worker started?
+
+private:
+  // ---------- SPSC ring buffer (core0 producer -> core1 consumer) ----------
+  static constexpr size_t QCAP = OTEL_QUEUE_CAPACITY;
+  static OTelQueuedItem q_[QCAP];
+  static std::atomic<size_t> head_;   // producer writes
+  static std::atomic<size_t> tail_;   // consumer writes
+  static std::atomic<uint32_t> drops_;
+  static std::atomic<bool>    worker_started_;
 
+  static bool enqueue_(const char* path, String&& payload);
+  static bool dequeue_(OTelQueuedItem& out);
+
+  // ---------- Worker ----------
+  static void pumpOnce_();   // send one item if present
+  static void workerLoop_(); // runs on core 1 (RP2040)
+  static void launchWorkerOnce_();
+
+  // ---------- Utilities ----------
+  static String fullUrl_(const char* path); // build collector URL + path
+
+  // inside class OTelSender (near the bottom)
+#ifdef ARDUINO_ARCH_RP2040
+  friend void otel_worker_entry();
 #endif
+};
 

library.json

@@ -1,6 +1,6 @@
 {
   "name": "otel-embedded-cpp",
-  "version": "1.0.1",
+  "version": "1.0.2",
   "description": "OpenTelemetry logging, tracing, and metrics for embedded C++ devices (ESP32, RP2040 Pico W, ESP8266).",
   "keywords": [
     "OpenTelemetry",
@@ -16,7 +16,7 @@
   ],
   "authors": [
     {
-      "name": "Your Name",
+      "name": "Matthew Macdonald-Wallace",
       "maintainer": true
     }
   ],

platformio.ini

@@ -15,8 +15,7 @@ lib_deps =
 build_flags =
   -DWIFI_SSID=\"${sysenv.WIFI_SSID}\"
   -DWIFI_PASS=\"${sysenv.WIFI_PASS}\"
-  -DOTEL_COLLECTOR_HOST=\"${sysenv.OTEL_COLLECTOR_HOST}\"
-  -DOTEL_COLLECTOR_PORT=${sysenv.OTEL_COLLECTOR_PORT}
+  -DOTEL_COLLECTOR_BASE_URL="\"http://192.168.8.10:4318\""
   -DOTEL_SERVICE_NAME=\"${sysenv.OTEL_SERVICE_NAME}\"
   -DOTEL_SERVICE_NAMESPACE=\"${sysenv.OTEL_SERVICE_NAMESPACE}\"
   -DOTEL_SERVICE_VERSION=\"${sysenv.OTEL_SERVICE_VERSION}\"
@@ -37,8 +36,7 @@ lib_deps =
 build_flags =
   -DWIFI_SSID=\"${sysenv.WIFI_SSID}\"
   -DWIFI_PASS=\"${sysenv.WIFI_PASS}\"
-  -DOTEL_COLLECTOR_HOST=\"${sysenv.OTEL_COLLECTOR_HOST}\"
-  -DOTEL_COLLECTOR_PORT=${sysenv.OTEL_COLLECTOR_PORT}
+  -DOTEL_COLLECTOR_BASE_URL="\"http://192.168.8.10:4318\""
   -DOTEL_SERVICE_NAME=\"${sysenv.OTEL_SERVICE_NAME}\"
   -DOTEL_SERVICE_NAMESPACE=\"${sysenv.OTEL_SERVICE_NAMESPACE}\"
   -DOTEL_SERVICE_VERSION=\"${sysenv.OTEL_SERVICE_VERSION}\"
@@ -59,10 +57,9 @@ lib_deps =
 build_flags =
   -DWIFI_SSID=\"${sysenv.WIFI_SSID}\"
   -DWIFI_PASS=\"${sysenv.WIFI_PASS}\"
-  -DOTEL_COLLECTOR_HOST=\"${sysenv.OTEL_COLLECTOR_HOST}\"
-  -DOTEL_COLLECTOR_PORT=${sysenv.OTEL_COLLECTOR_PORT}
+  -DOTEL_COLLECTOR_BASE_URL="\"http://192.168.8.10:4318\""
   -DOTEL_SERVICE_NAME=\"${sysenv.OTEL_SERVICE_NAME}\"
   -DOTEL_SERVICE_NAMESPACE=\"${sysenv.OTEL_SERVICE_NAMESPACE}\"
   -DOTEL_SERVICE_VERSION=\"${sysenv.OTEL_SERVICE_VERSION}\"
-  -DOTEL_SERVICE_INSTANCE=\"${sysenv.OTEL_SERVICE_INSTANCE}\"
-  -DOTEL_DEPLOY_ENV=\"${sysenv.OTEL_DEPLOY_ENV}\"
+  -DOTEL_SERVICE_INSTANCE=\"esp8266\"
+  -DOTEL_DEPLOY_ENV=\"esp8266\"