Logging framework first pass

README.md

@@ -95,6 +95,37 @@ void loop() {
 }
 ```
 
+## Using the logging API
+
+As an addon to the Ubsub API, there is also a simple logging API
+to help you send out log messages to ubsub (in additional to serial/stdout).
+
+### Configuration
+```
+ULOG_DISABLE        Disable all logging if defined (macro to nothing)
+ULOG_BUF_SIZE       Override default buffer size (default: 512)
+ULOG_TOPIC          Override topic to write log messages to (default: "log")
+ULOG_SERIAL         Enable serial output (or stdout if unix)
+ULOG_DEBUG          If defined, will enable UDEBUG macro output
+```
+
+### Example
+```cpp
+#include "ubsub_log.h"
+
+void setup() {
+  initUbsubLogger("id", "key");
+
+  // If you already have an ubsub instance:
+  // initUbsubLogger(&ubsub);
+
+  ULOG("hi there %s", "name");
+  UWARN("...");
+  UERROR("...");
+  UDEBUG("...");
+}
+```
+
 # API
 
 ## Ubsub(const char* deviceId, const char* deviceKey)

examples/unix/main.cpp

@@ -1,6 +1,7 @@
 #include <iostream>
 #include <unistd.h>
 #include "../../src/ubsub.h"
+#include "../../src/ubsub_log.h"
 
 void myMethod(const char* arg) {
   std::cout << "RECEIVED: " << arg << std::endl;
@@ -13,8 +14,12 @@ int main() {
   if (!client.connect(2)) {
     std::cout << "Failed to connect" << std::endl;
   }
+  initUbsubLogger(&client);
+  // setLoggerDeviceId("test");
   // client.enableAutoRetry(false);
 
+  UINFO("Welcome to the logging test!");
+
   client.listenToTopic("testy", myMethod);
 
   client.publishEvent("Byg2kKB3SZ", "HJ3ytS3SW", "Hi there");
@@ -27,6 +32,8 @@ int main() {
   client.watchVariable("other", &test);
   client.watchVariable("var", &test); // Any time this value changes, an event will be emitted
 
+  UWARN("Done with watch %d", test);
+
   while(true) {
     test++;
     client.processEvents();

src/ubsub_log.h

@@ -0,0 +1,114 @@
+/**
+Ubsub log wrapper to send log events to ubsub (or other sources)
+
+Configuration:
+ULOG_DISABLE        Disable all logging if defined (macro to nothing)
+ULOG_BUF_SIZE       Override default buffer size (default: 512)
+ULOG_TOPIC          Override topic to write log messages to (default: "log")
+ULOG_SERIAL         Enable serial output (or stdout if unix)
+ULOG_DEBUG          If defined, will enable UDEBUG macro output
+**/
+
+#ifndef ubsub_log_h
+#define ubsub_log_h
+
+#ifndef ULOG_DISABLE
+
+  #if (!ARDUINO || PARTICLE)
+    #include <iostream>
+    #include <stdio.h>
+    #include <stdarg.h>
+  #else
+    #warning Logs are enabled on IoT device, may consume extra string memory!
+    #include <Arduino.h>
+  #endif
+  #include <string.h>
+  #include "ubsub.h"
+  #include "minijson.h"
+
+  #ifndef ULOG_BUF_SIZE
+  #define ULOG_BUF_SIZE 512
+  #endif
+
+  #ifndef ULOG_TOPIC
+  #define ULOG_TOPIC "log"
+  #endif
+
+  static const char* _deviceId = NULL;
+  static Ubsub* _conn = NULL;
+
+  void initUbsubLogger(const char *deviceId, const char *deviceKey) {
+    if (_conn == NULL) {
+      _conn = new Ubsub(deviceId, deviceKey);
+      _conn->enableAutoRetry(false);
+      _conn->connect();
+    }
+  }
+  void initUbsubLogger(Ubsub* conn) {
+    _conn = conn;
+  }
+  void setLoggerDeviceId(const char* deviceId) {
+    _deviceId = strdup(deviceId);
+  }
+  void shutdownLogger() {
+    if (_conn != NULL) {
+      delete _conn;
+      _conn = NULL;
+    }
+  }
+
+  static void writeULog(const char* level, const char* filename, int line, const char* msg, ...) {
+    static char logbuf[ULOG_BUF_SIZE];
+    va_list argptr;
+    va_start(argptr, msg);
+    vsnprintf(logbuf, sizeof(logbuf), msg, argptr);
+    va_end(argptr);
+
+    #ifdef ULOG_SERIAL
+      #if ARDUINO || PARTICLE
+        Serial.printf("[%s] (%s:%d) %s\n", level, filename, line, logbuf);
+        Serial.flush();
+      #else
+        std::cerr << "[" << level << "] (" << filename << ":" << line << ") " << logbuf << std::endl;
+      #endif
+    #endif
+
+    if (_conn != NULL) {
+      char jsonBuf[ULOG_BUF_SIZE]; // Buffer on stack
+      MiniJsonBuilder json(jsonBuf, ULOG_BUF_SIZE);
+      json.open()
+        .write("level", level)
+        .write("filename", filename)
+        .write("line", line)
+        .write("msg", logbuf);
+      if (_deviceId != NULL) {
+        json.write("device", _deviceId);
+      }
+      json.close();
+
+      _conn->callFunction(ULOG_TOPIC, json.c_str());
+    }
+  }
+
+  #define UINFO(msg, ...)  writeULog("INFO", __FILE__, __LINE__, msg, ## __VA_ARGS__)
+  #define UWARN(msg, ...)  writeULog("WARN", __FILE__, __LINE__, msg, ## __VA_ARGS__)
+  #define UERROR(msg, ...) writeULog("ERROR", __FILE__, __LINE__, msg, ## __VA_ARGS__)
+  #ifdef ULOG_DEBUG
+    #define UDEBUG(msg, ...) writeULog("DEBUG", __FILE__, __LINE__, msg, ## __VA_ARGS__)
+  #else
+    #define UDEBUG(msg, ...)
+  #endif
+
+#else
+  // Ubsub log disabled, nullify log statements
+  #define initUbsubLogger
+  #define setLoggerDeviceId
+  #define shutdownLogger
+
+  #define UINFO(msg, ...)
+  #define UWARN(msg, ...)
+  #define UERROR(msg, ...)
+  #define UDEBUG(msg, ...)
+#endif
+
+#endif