feat(task): Add espp::task::run_on_core_non_blocking static method (#331)

Author: finger563

components/task/example/main/task_example.cpp

@@ -530,6 +530,29 @@ extern "C" void app_main(void) {
     //! [run on core example]
   }
 
+  {
+    //! [run on core nonblocking example]
+    logger.info("espp::task::run_on_core non-blocking example: main thread core ID: {}",
+                xPortGetCoreID());
+    // NOTE: in these examples, because we're logging with libfmt in the
+    // function to be run, we need a little more than the default 2k stack size,
+    // so we're using 3k.
+
+    // test running a function which takes a while to complete
+    auto task_fn = []() -> void {
+      fmt::print("[{0}] Task running on core {0}\n", xPortGetCoreID());
+      std::this_thread::sleep_for(1s);
+      fmt::print("[{0}] Task done!\n", xPortGetCoreID());
+    };
+    espp::task::run_on_core_non_blocking(task_fn, 0, 3 * 1024);
+    espp::task::run_on_core_non_blocking(task_fn, 1);
+    fmt::print("Started tasks on cores 0 and 1\n");
+
+    // sleep for a bit to let the tasks run
+    std::this_thread::sleep_for(2s);
+    //! [run on core nonblocking example]
+  }
+
   logger.info("Task example complete!");
 
   while (true) {

components/task/include/run_on_core.hpp

@@ -82,6 +82,46 @@ static auto run_on_core(const auto &f, int core_id, size_t stack_size_bytes = 20
     }
   }
 }
+
+/// Run the given function on the specific core without blocking the calling thread
+/// @details This function will run the given function on the specified core,
+///          without blocking the calling thread / context. A new thread is
+///          spawned for the function even if the requested core is the same as
+///          the core on which the calling thread is running.
+/// @param f The function to run
+/// @param core_id The core to run the function on
+/// @param stack_size_bytes The stack size to allocate for the function
+/// @param priority The priority of the task
+/// @note This function is only available on ESP32
+/// @note If you provide a core_id < 0, the thread will not be pinned to any
+///       specific core, instead the scheduler will decide which core to run
+///       the thread on
+/// @note If you provide a core_id >= configNUM_CORES, the function will run on
+///       the last core
+static void run_on_core_non_blocking(const auto &f, int core_id, size_t stack_size_bytes = 2048,
+                                     size_t priority = 5) {
+  // Otherwise run the function on the desired core
+  if (core_id > configNUM_CORES - 1) {
+    // If the core id is larger than the number of cores, run on the last core
+    core_id = configNUM_CORES - 1;
+  }
+  auto thread_config = esp_pthread_get_default_config();
+  thread_config.thread_name = "run_on_core_thread";
+  if (core_id >= 0)
+    thread_config.pin_to_core = core_id;
+  thread_config.stack_size = stack_size_bytes;
+  thread_config.prio = priority;
+  // this will set the config for the next created thread
+  auto err = esp_pthread_set_cfg(&thread_config);
+  if (err != ESP_OK) {
+    // failed to set the config, can't create the thread; simply run the function
+    // on the current core
+    f();
+    return;
+  }
+  auto thread = std::thread(f);
+  thread.detach();
+}
 #endif
 } // namespace task
 } // namespace espp

components/task/include/task.hpp

@@ -44,6 +44,8 @@ namespace espp {
  *
  * \section run_on_core_ex1 Run on Core Example
  * \snippet task_example.cpp run on core example
+ * \section run_on_core_ex2 Run on Core (Non-Blocking) Example
+ * \snippet task_example.cpp run on core nonblocking example
  */
 class Task : public espp::BaseComponent {
 public: