refactor(profiling): split upload function

Author: KowalskiThomas

libdd-profiling-ffi/src/exporter.rs

@@ -222,8 +222,38 @@ unsafe fn parse_json(
     }
 }
 
+/// Initializes the tokio runtime for the exporter.
+///
+/// This function creates the tokio runtime used by `ddog_prof_Exporter_send_blocking`.
+/// It can be called ahead of time to ensure the runtime is ready before sending.
+///
+/// # Thread Affinity
+///
+/// **Important**: The runtime has thread affinity. This function should be called from
+/// the same thread that will later call `ddog_prof_Exporter_send_blocking`.
+///
+/// # Arguments
+/// * `exporter` - Borrows the exporter.
+///
+/// # Safety
+/// The `exporter` must point to a valid ProfileExporter that has not been dropped.
+#[no_mangle]
+#[must_use]
+#[named]
+pub unsafe extern "C" fn ddog_prof_Exporter_init_runtime(
+    mut exporter: *mut Handle<ProfileExporter>,
+) -> VoidResult {
+    wrap_with_void_ffi_result!({
+        let exporter = exporter.to_inner_mut()?;
+        exporter.init_runtime()?
+    })
+}
+
 /// Builds a request and sends it, returning the HttpStatus.
 ///
+/// Note: If the runtime has not been initialized via `ddog_prof_Exporter_init_runtime`,
+/// it will be lazily initialized on first call.
+///
 /// # Arguments
 /// * `exporter` - Borrows the exporter.
 /// * `profile` - Takes ownership of the profile.

libdd-profiling/src/exporter/profile_exporter.rs

@@ -152,6 +152,26 @@ impl ProfileExporter {
     /// - Using the async [`send`] method directly from within a tokio runtime
     ///
     /// [`send`]: ProfileExporter::send
+    /// Initializes the tokio runtime for blocking operations.
+    ///
+    /// This method lazily creates a single-threaded tokio runtime. It can be called
+    /// before `send_blocking` to ensure the runtime is ready ahead of time.
+    ///
+    /// # Thread Affinity
+    ///
+    /// **Important**: The runtime uses `new_current_thread()`, which has thread affinity.
+    /// This method should be called from the same thread that will later call `send_blocking`.
+    pub fn init_runtime(&mut self) -> anyhow::Result<()> {
+        if self.runtime.is_none() {
+            self.runtime = Some(
+                tokio::runtime::Builder::new_current_thread()
+                    .enable_all()
+                    .build()?,
+            );
+        }
+        Ok(())
+    }
+
     #[allow(clippy::too_many_arguments)]
     pub fn send_blocking(
         &mut self,
@@ -163,13 +183,7 @@ impl ProfileExporter {
         process_tags: Option<&str>,
         cancel: Option<&CancellationToken>,
     ) -> anyhow::Result<reqwest::StatusCode> {
-        if self.runtime.is_none() {
-            self.runtime = Some(
-                tokio::runtime::Builder::new_current_thread()
-                    .enable_all()
-                    .build()?,
-            );
-        }
+        self.init_runtime()?;
 
         Ok(self
             .runtime