feat: OpenTelemetry Tracing API and Exporting (#26710)

Initial import of OTEL code supporting tracing. Metrics soon to come.
Implements APIs for https://jsr.io/@deno/otel so that code using
OpenTelemetry.js just works tm.

There is still a lot of work to do with configuration and adding
built-in tracing to core APIs, which will come in followup PRs.

---------

Co-authored-by: Luca Casonato <hello@lcas.dev>

3 files changed, 689 insertions, 0 deletions

diff --git a/runtime/ops/mod.rs b/runtime/ops/mod.rs
index 67065b901..c2e402f33 100644
--- a/runtime/ops/mod.rs
+++ b/runtime/ops/mod.rs
@@ -4,6 +4,7 @@ pub mod bootstrap;
 pub mod fs_events;
 pub mod http;
 pub mod os;
+pub mod otel;
 pub mod permissions;
 pub mod process;
 pub mod runtime;
diff --git a/runtime/ops/os/mod.rs b/runtime/ops/os/mod.rs
index 9bee9d823..790962f38 100644
--- a/runtime/ops/os/mod.rs
+++ b/runtime/ops/os/mod.rs
@@ -186,6 +186,8 @@ fn op_get_exit_code(state: &mut OpState) -> i32 {
 
 #[op2(fast)]
 fn op_exit(state: &mut OpState) {
+  crate::ops::otel::otel_drop_state(state);
+
   let code = state.borrow::<ExitCode>().get();
   std::process::exit(code)
 }
diff --git a/runtime/ops/otel.rs b/runtime/ops/otel.rs
new file mode 100644
index 000000000..6a4750acc
--- /dev/null
+++ b/runtime/ops/otel.rs
@@ -0,0 +1,686 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+
+use crate::tokio_util::create_basic_runtime;
+use deno_core::anyhow::anyhow;
+use deno_core::anyhow::{self};
+use deno_core::futures::channel::mpsc;
+use deno_core::futures::channel::mpsc::UnboundedSender;
+use deno_core::futures::future::BoxFuture;
+use deno_core::futures::stream;
+use deno_core::futures::Stream;
+use deno_core::futures::StreamExt;
+use deno_core::op2;
+use deno_core::v8;
+use deno_core::OpState;
+use once_cell::sync::Lazy;
+use opentelemetry::logs::Severity;
+use opentelemetry::trace::SpanContext;
+use opentelemetry::trace::SpanId;
+use opentelemetry::trace::SpanKind;
+use opentelemetry::trace::Status as SpanStatus;
+use opentelemetry::trace::TraceFlags;
+use opentelemetry::trace::TraceId;
+use opentelemetry::InstrumentationScope;
+use opentelemetry::Key;
+use opentelemetry::KeyValue;
+use opentelemetry::StringValue;
+use opentelemetry::Value;
+use opentelemetry_otlp::HttpExporterBuilder;
+use opentelemetry_otlp::Protocol;
+use opentelemetry_otlp::WithExportConfig;
+use opentelemetry_otlp::WithHttpConfig;
+use opentelemetry_sdk::export::trace::SpanData;
+use opentelemetry_sdk::logs::BatchLogProcessor;
+use opentelemetry_sdk::logs::LogProcessor as LogProcessorTrait;
+use opentelemetry_sdk::logs::LogRecord;
+use opentelemetry_sdk::trace::BatchSpanProcessor;
+use opentelemetry_sdk::trace::SpanProcessor as SpanProcessorTrait;
+use opentelemetry_sdk::Resource;
+use opentelemetry_semantic_conventions::resource::PROCESS_RUNTIME_NAME;
+use opentelemetry_semantic_conventions::resource::PROCESS_RUNTIME_VERSION;
+use opentelemetry_semantic_conventions::resource::TELEMETRY_SDK_LANGUAGE;
+use opentelemetry_semantic_conventions::resource::TELEMETRY_SDK_NAME;
+use opentelemetry_semantic_conventions::resource::TELEMETRY_SDK_VERSION;
+use serde::Deserialize;
+use serde::Serialize;
+use std::borrow::Cow;
+use std::env;
+use std::fmt::Debug;
+use std::pin::Pin;
+use std::task::Context;
+use std::task::Poll;
+use std::thread;
+use std::time::Duration;
+use std::time::SystemTime;
+
+type SpanProcessor = BatchSpanProcessor<OtelSharedRuntime>;
+type LogProcessor = BatchLogProcessor<OtelSharedRuntime>;
+
+deno_core::extension!(
+  deno_otel,
+  ops = [op_otel_log, op_otel_span_start, op_otel_span_continue, op_otel_span_attribute, op_otel_span_attribute2, op_otel_span_attribute3, op_otel_span_flush],
+  options = {
+    otel_config: Option<OtelConfig>, // `None` means OpenTelemetry is disabled.
+  },
+  state = |state, options| {
+    if let Some(otel_config) = options.otel_config {
+      otel_create_globals(otel_config, state).unwrap();
+    }
+  }
+);
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct OtelConfig {
+  pub runtime_name: Cow<'static, str>,
+  pub runtime_version: Cow<'static, str>,
+  pub console: OtelConsoleConfig,
+}
+
+#[derive(Debug, Clone, Copy, Serialize, Deserialize)]
+#[repr(u8)]
+pub enum OtelConsoleConfig {
+  Ignore = 0,
+  Capture = 1,
+  Replace = 2,
+}
+
+impl Default for OtelConfig {
+  fn default() -> Self {
+    Self {
+      runtime_name: Cow::Borrowed(env!("CARGO_PKG_NAME")),
+      runtime_version: Cow::Borrowed(env!("CARGO_PKG_VERSION")),
+      console: OtelConsoleConfig::Capture,
+    }
+  }
+}
+
+static OTEL_SHARED_RUNTIME_SPAWN_TASK_TX: Lazy<
+  UnboundedSender<BoxFuture<'static, ()>>,
+> = Lazy::new(otel_create_shared_runtime);
+
+fn otel_create_shared_runtime() -> UnboundedSender<BoxFuture<'static, ()>> {
+  let (spawn_task_tx, mut spawn_task_rx) =
+    mpsc::unbounded::<BoxFuture<'static, ()>>();
+
+  thread::spawn(move || {
+    let rt = create_basic_runtime();
+    rt.block_on(async move {
+      while let Some(task) = spawn_task_rx.next().await {
+        tokio::spawn(task);
+      }
+    });
+  });
+
+  spawn_task_tx
+}
+
+#[derive(Clone, Copy)]
+struct OtelSharedRuntime;
+
+impl hyper::rt::Executor<BoxFuture<'static, ()>> for OtelSharedRuntime {
+  fn execute(&self, fut: BoxFuture<'static, ()>) {
+    (*OTEL_SHARED_RUNTIME_SPAWN_TASK_TX)
+      .unbounded_send(fut)
+      .expect("failed to send task to shared OpenTelemetry runtime");
+  }
+}
+
+impl opentelemetry_sdk::runtime::Runtime for OtelSharedRuntime {
+  type Interval = Pin<Box<dyn Stream<Item = ()> + Send + 'static>>;
+  type Delay = Pin<Box<tokio::time::Sleep>>;
+
+  fn interval(&self, period: Duration) -> Self::Interval {
+    stream::repeat(())
+      .then(move |_| tokio::time::sleep(period))
+      .boxed()
+  }
+
+  fn spawn(&self, future: BoxFuture<'static, ()>) {
+    (*OTEL_SHARED_RUNTIME_SPAWN_TASK_TX)
+      .unbounded_send(future)
+      .expect("failed to send task to shared OpenTelemetry runtime");
+  }
+
+  fn delay(&self, duration: Duration) -> Self::Delay {
+    Box::pin(tokio::time::sleep(duration))
+  }
+}
+
+impl opentelemetry_sdk::runtime::RuntimeChannel for OtelSharedRuntime {
+  type Receiver<T: Debug + Send> = BatchMessageChannelReceiver<T>;
+  type Sender<T: Debug + Send> = BatchMessageChannelSender<T>;
+
+  fn batch_message_channel<T: Debug + Send>(
+    &self,
+    capacity: usize,
+  ) -> (Self::Sender<T>, Self::Receiver<T>) {
+    let (batch_tx, batch_rx) = tokio::sync::mpsc::channel::<T>(capacity);
+    (batch_tx.into(), batch_rx.into())
+  }
+}
+
+#[derive(Debug)]
+pub struct BatchMessageChannelSender<T: Send> {
+  sender: tokio::sync::mpsc::Sender<T>,
+}
+
+impl<T: Send> From<tokio::sync::mpsc::Sender<T>>
+  for BatchMessageChannelSender<T>
+{
+  fn from(sender: tokio::sync::mpsc::Sender<T>) -> Self {
+    Self { sender }
+  }
+}
+
+impl<T: Send> opentelemetry_sdk::runtime::TrySend
+  for BatchMessageChannelSender<T>
+{
+  type Message = T;
+
+  fn try_send(
+    &self,
+    item: Self::Message,
+  ) -> Result<(), opentelemetry_sdk::runtime::TrySendError> {
+    self.sender.try_send(item).map_err(|err| match err {
+      tokio::sync::mpsc::error::TrySendError::Full(_) => {
+        opentelemetry_sdk::runtime::TrySendError::ChannelFull
+      }
+      tokio::sync::mpsc::error::TrySendError::Closed(_) => {
+        opentelemetry_sdk::runtime::TrySendError::ChannelClosed
+      }
+    })
+  }
+}
+
+pub struct BatchMessageChannelReceiver<T> {
+  receiver: tokio::sync::mpsc::Receiver<T>,
+}
+
+impl<T> From<tokio::sync::mpsc::Receiver<T>>
+  for BatchMessageChannelReceiver<T>
+{
+  fn from(receiver: tokio::sync::mpsc::Receiver<T>) -> Self {
+    Self { receiver }
+  }
+}
+
+impl<T> Stream for BatchMessageChannelReceiver<T> {
+  type Item = T;
+
+  fn poll_next(
+    mut self: Pin<&mut Self>,
+    cx: &mut Context<'_>,
+  ) -> Poll<Option<Self::Item>> {
+    self.receiver.poll_recv(cx)
+  }
+}
+
+mod hyper_client {
+  use http_body_util::BodyExt;
+  use http_body_util::Full;
+  use hyper::body::Body as HttpBody;
+  use hyper::body::Frame;
+  use hyper_util::client::legacy::connect::HttpConnector;
+  use hyper_util::client::legacy::Client;
+  use opentelemetry_http::Bytes;
+  use opentelemetry_http::HttpError;
+  use opentelemetry_http::Request;
+  use opentelemetry_http::Response;
+  use opentelemetry_http::ResponseExt;
+  use std::fmt::Debug;
+  use std::pin::Pin;
+  use std::task::Poll;
+  use std::task::{self};
+
+  use super::OtelSharedRuntime;
+
+  // same as opentelemetry_http::HyperClient except it uses OtelSharedRuntime
+  #[derive(Debug, Clone)]
+  pub struct HyperClient {
+    inner: Client<HttpConnector, Body>,
+  }
+
+  impl HyperClient {
+    pub fn new() -> Self {
+      Self {
+        inner: Client::builder(OtelSharedRuntime).build(HttpConnector::new()),
+      }
+    }
+  }
+
+  #[async_trait::async_trait]
+  impl opentelemetry_http::HttpClient for HyperClient {
+    async fn send(
+      &self,
+      request: Request<Vec<u8>>,
+    ) -> Result<Response<Bytes>, HttpError> {
+      let (parts, body) = request.into_parts();
+      let request = Request::from_parts(parts, Body(Full::from(body)));
+      let mut response = self.inner.request(request).await?;
+      let headers = std::mem::take(response.headers_mut());
+
+      let mut http_response = Response::builder()
+        .status(response.status())
+        .body(response.into_body().collect().await?.to_bytes())?;
+      *http_response.headers_mut() = headers;
+
+      Ok(http_response.error_for_status()?)
+    }
+  }
+
+  #[pin_project::pin_project]
+  pub struct Body(#[pin] Full<Bytes>);
+
+  impl HttpBody for Body {
+    type Data = Bytes;
+    type Error = Box<dyn std::error::Error + Send + Sync + 'static>;
+
+    #[inline]
+    fn poll_frame(
+      self: Pin<&mut Self>,
+      cx: &mut task::Context<'_>,
+    ) -> Poll<Option<Result<Frame<Self::Data>, Self::Error>>> {
+      self.project().0.poll_frame(cx).map_err(Into::into)
+    }
+
+    #[inline]
+    fn is_end_stream(&self) -> bool {
+      self.0.is_end_stream()
+    }
+
+    #[inline]
+    fn size_hint(&self) -> hyper::body::SizeHint {
+      self.0.size_hint()
+    }
+  }
+}
+
+fn otel_create_globals(
+  config: OtelConfig,
+  op_state: &mut OpState,
+) -> anyhow::Result<()> {
+  // Parse the `OTEL_EXPORTER_OTLP_PROTOCOL` variable. The opentelemetry_*
+  // crates don't do this automatically.
+  // TODO(piscisaureus): enable GRPC support.
+  let protocol = match env::var("OTEL_EXPORTER_OTLP_PROTOCOL").as_deref() {
+    Ok("http/protobuf") => Protocol::HttpBinary,
+    Ok("http/json") => Protocol::HttpJson,
+    Ok("") | Err(env::VarError::NotPresent) => {
+      return Ok(());
+    }
+    Ok(protocol) => {
+      return Err(anyhow!(
+        "Env var OTEL_EXPORTER_OTLP_PROTOCOL specifies an unsupported protocol: {}",
+        protocol
+      ));
+    }
+    Err(err) => {
+      return Err(anyhow!(
+        "Failed to read env var OTEL_EXPORTER_OTLP_PROTOCOL: {}",
+        err
+      ))
+    }
+  };
+
+  // Define the resource attributes that will be attached to all log records.
+  // These attributes are sourced as follows (in order of precedence):
+  //   * The `service.name` attribute from the `OTEL_SERVICE_NAME` env var.
+  //   * Additional attributes from the `OTEL_RESOURCE_ATTRIBUTES` env var.
+  //   * Default attribute values defined here.
+  // TODO(piscisaureus): add more default attributes (e.g. script path).
+  let mut resource = Resource::default();
+
+  // Add the runtime name and version to the resource attributes. Also override
+  // the `telemetry.sdk` attributes to include the Deno runtime.
+  resource = resource.merge(&Resource::new(vec![
+    KeyValue::new(PROCESS_RUNTIME_NAME, config.runtime_name),
+    KeyValue::new(PROCESS_RUNTIME_VERSION, config.runtime_version.clone()),
+    KeyValue::new(
+      TELEMETRY_SDK_LANGUAGE,
+      format!(
+        "deno-{}",
+        resource.get(Key::new(TELEMETRY_SDK_LANGUAGE)).unwrap()
+      ),
+    ),
+    KeyValue::new(
+      TELEMETRY_SDK_NAME,
+      format!(
+        "deno-{}",
+        resource.get(Key::new(TELEMETRY_SDK_NAME)).unwrap()
+      ),
+    ),
+    KeyValue::new(
+      TELEMETRY_SDK_VERSION,
+      format!(
+        "{}-{}",
+        config.runtime_version,
+        resource.get(Key::new(TELEMETRY_SDK_VERSION)).unwrap()
+      ),
+    ),
+  ]));
+
+  // The OTLP endpoint is automatically picked up from the
+  // `OTEL_EXPORTER_OTLP_ENDPOINT` environment variable. Additional headers can
+  // be specified using `OTEL_EXPORTER_OTLP_HEADERS`.
+
+  let client = hyper_client::HyperClient::new();
+
+  let span_exporter = HttpExporterBuilder::default()
+    .with_http_client(client.clone())
+    .with_protocol(protocol)
+    .build_span_exporter()?;
+  let mut span_processor =
+    BatchSpanProcessor::builder(span_exporter, OtelSharedRuntime).build();
+  span_processor.set_resource(&resource);
+  op_state.put::<SpanProcessor>(span_processor);
+
+  let log_exporter = HttpExporterBuilder::default()
+    .with_http_client(client)
+    .with_protocol(protocol)
+    .build_log_exporter()?;
+  let log_processor =
+    BatchLogProcessor::builder(log_exporter, OtelSharedRuntime).build();
+  log_processor.set_resource(&resource);
+  op_state.put::<LogProcessor>(log_processor);
+
+  Ok(())
+}
+
+/// This function is called by the runtime whenever it is about to call
+/// `os::process::exit()`, to ensure that all OpenTelemetry logs are properly
+/// flushed before the process terminates.
+pub fn otel_drop_state(state: &mut OpState) {
+  if let Some(processor) = state.try_take::<SpanProcessor>() {
+    let _ = processor.force_flush();
+    drop(processor);
+  }
+  if let Some(processor) = state.try_take::<LogProcessor>() {
+    let _ = processor.force_flush();
+    drop(processor);
+  }
+}
+
+#[op2(fast)]
+fn op_otel_log(
+  state: &mut OpState,
+  #[string] message: String,
+  #[smi] level: i32,
+  #[string] trace_id: &str,
+  #[string] span_id: &str,
+  #[smi] trace_flags: u8,
+) {
+  let Some(logger) = state.try_borrow::<LogProcessor>() else {
+    log::error!("op_otel_log: OpenTelemetry Logger not available");
+    return;
+  };
+
+  // Convert the integer log level that ext/console uses to the corresponding
+  // OpenTelemetry log severity.
+  let severity = match level {
+    ..=0 => Severity::Debug,
+    1 => Severity::Info,
+    2 => Severity::Warn,
+    3.. => Severity::Error,
+  };
+
+  let mut log_record = LogRecord::default();
+
+  log_record.observed_timestamp = Some(SystemTime::now());
+  log_record.body = Some(message.into());
+  log_record.severity_number = Some(severity);
+  log_record.severity_text = Some(severity.name());
+  if let (Ok(trace_id), Ok(span_id)) =
+    (TraceId::from_hex(trace_id), SpanId::from_hex(span_id))
+  {
+    let span_context = SpanContext::new(
+      trace_id,
+      span_id,
+      TraceFlags::new(trace_flags),
+      false,
+      Default::default(),
+    );
+    log_record.trace_context = Some((&span_context).into());
+  }
+  logger.emit(
+    &mut log_record,
+    &InstrumentationScope::builder("deno").build(),
+  );
+}
+
+struct TemporarySpan(SpanData);
+
+#[allow(clippy::too_many_arguments)]
+#[op2(fast)]
+fn op_otel_span_start<'s>(
+  scope: &mut v8::HandleScope<'s>,
+  state: &mut OpState,
+  trace_id: v8::Local<'s, v8::Value>,
+  span_id: v8::Local<'s, v8::Value>,
+  parent_span_id: v8::Local<'s, v8::Value>,
+  #[smi] span_kind: u8,
+  name: v8::Local<'s, v8::Value>,
+  start_time: f64,
+  end_time: f64,
+) -> Result<(), anyhow::Error> {
+  if let Some(temporary_span) = state.try_take::<TemporarySpan>() {
+    let Some(span_processor) = state.try_borrow::<SpanProcessor>() else {
+      return Ok(());
+    };
+    span_processor.on_end(temporary_span.0);
+  };
+
+  let trace_id = {
+    let x = v8::ValueView::new(scope, trace_id.try_cast()?);
+    match x.data() {
+      v8::ValueViewData::OneByte(bytes) => {
+        TraceId::from_hex(&String::from_utf8_lossy(bytes))?
+      }
+      _ => return Err(anyhow!("invalid trace_id")),
+    }
+  };
+
+  let span_id = {
+    let x = v8::ValueView::new(scope, span_id.try_cast()?);
+    match x.data() {
+      v8::ValueViewData::OneByte(bytes) => {
+        SpanId::from_hex(&String::from_utf8_lossy(bytes))?
+      }
+      _ => return Err(anyhow!("invalid span_id")),
+    }
+  };
+
+  let parent_span_id = {
+    let x = v8::ValueView::new(scope, parent_span_id.try_cast()?);
+    match x.data() {
+      v8::ValueViewData::OneByte(bytes) => {
+        let s = String::from_utf8_lossy(bytes);
+        if s.is_empty() {
+          SpanId::INVALID
+        } else {
+          SpanId::from_hex(&s)?
+        }
+      }
+      _ => return Err(anyhow!("invalid parent_span_id")),
+    }
+  };
+
+  let name = {
+    let x = v8::ValueView::new(scope, name.try_cast()?);
+    match x.data() {
+      v8::ValueViewData::OneByte(bytes) => {
+        String::from_utf8_lossy(bytes).into_owned()
+      }
+      v8::ValueViewData::TwoByte(bytes) => String::from_utf16_lossy(bytes),
+    }
+  };
+
+  let temporary_span = TemporarySpan(SpanData {
+    span_context: SpanContext::new(
+      trace_id,
+      span_id,
+      TraceFlags::SAMPLED,
+      false,
+      Default::default(),
+    ),
+    parent_span_id,
+    span_kind: match span_kind {
+      0 => SpanKind::Internal,
+      1 => SpanKind::Server,
+      2 => SpanKind::Client,
+      3 => SpanKind::Producer,
+      4 => SpanKind::Consumer,
+      _ => return Err(anyhow!("invalid span kind")),
+    },
+    name: Cow::Owned(name),
+    start_time: SystemTime::UNIX_EPOCH
+      .checked_add(std::time::Duration::from_secs_f64(start_time))
+      .ok_or_else(|| anyhow!("invalid start time"))?,
+    end_time: SystemTime::UNIX_EPOCH
+      .checked_add(std::time::Duration::from_secs_f64(end_time))
+      .ok_or_else(|| anyhow!("invalid start time"))?,
+    attributes: Vec::new(),
+    dropped_attributes_count: 0,
+    events: Default::default(),
+    links: Default::default(),
+    status: SpanStatus::Unset,
+    instrumentation_scope: InstrumentationScope::builder("deno").build(),
+  });
+  state.put(temporary_span);
+
+  Ok(())
+}
+
+#[op2(fast)]
+fn op_otel_span_continue(
+  state: &mut OpState,
+  #[smi] status: u8,
+  #[string] error_description: Cow<'_, str>,
+) {
+  if let Some(temporary_span) = state.try_borrow_mut::<TemporarySpan>() {
+    temporary_span.0.status = match status {
+      0 => SpanStatus::Unset,
+      1 => SpanStatus::Ok,
+      2 => SpanStatus::Error {
+        description: Cow::Owned(error_description.into_owned()),
+      },
+      _ => return,
+    };
+  }
+}
+
+macro_rules! attr {
+  ($scope:ident, $temporary_span:ident, $name:ident, $value:ident) => {
+    let name = if let Ok(name) = $name.try_cast() {
+      let view = v8::ValueView::new($scope, name);
+      match view.data() {
+        v8::ValueViewData::OneByte(bytes) => {
+          Some(String::from_utf8_lossy(bytes).into_owned())
+        }
+        v8::ValueViewData::TwoByte(bytes) => {
+          Some(String::from_utf16_lossy(bytes))
+        }
+      }
+    } else {
+      None
+    };
+    let value = if let Ok(string) = $value.try_cast::<v8::String>() {
+      Some(Value::String(StringValue::from({
+        let x = v8::ValueView::new($scope, string);
+        match x.data() {
+          v8::ValueViewData::OneByte(bytes) => {
+            String::from_utf8_lossy(bytes).into_owned()
+          }
+          v8::ValueViewData::TwoByte(bytes) => String::from_utf16_lossy(bytes),
+        }
+      })))
+    } else if let Ok(number) = $value.try_cast::<v8::Number>() {
+      Some(Value::F64(number.value()))
+    } else if let Ok(boolean) = $value.try_cast::<v8::Boolean>() {
+      Some(Value::Bool(boolean.is_true()))
+    } else if let Ok(bigint) = $value.try_cast::<v8::BigInt>() {
+      let (i64_value, _lossless) = bigint.i64_value();
+      Some(Value::I64(i64_value))
+    } else {
+      None
+    };
+    if let (Some(name), Some(value)) = (name, value) {
+      $temporary_span
+        .0
+        .attributes
+        .push(KeyValue::new(name, value));
+    } else {
+      $temporary_span.0.dropped_attributes_count += 1;
+    }
+  };
+}
+
+#[op2(fast)]
+fn op_otel_span_attribute<'s>(
+  scope: &mut v8::HandleScope<'s>,
+  state: &mut OpState,
+  #[smi] capacity: u32,
+  key: v8::Local<'s, v8::Value>,
+  value: v8::Local<'s, v8::Value>,
+) {
+  if let Some(temporary_span) = state.try_borrow_mut::<TemporarySpan>() {
+    temporary_span.0.attributes.reserve_exact(
+      (capacity as usize) - temporary_span.0.attributes.capacity(),
+    );
+    attr!(scope, temporary_span, key, value);
+  }
+}
+
+#[op2(fast)]
+fn op_otel_span_attribute2<'s>(
+  scope: &mut v8::HandleScope<'s>,
+  state: &mut OpState,
+  #[smi] capacity: u32,
+  key1: v8::Local<'s, v8::Value>,
+  value1: v8::Local<'s, v8::Value>,
+  key2: v8::Local<'s, v8::Value>,
+  value2: v8::Local<'s, v8::Value>,
+) {
+  if let Some(temporary_span) = state.try_borrow_mut::<TemporarySpan>() {
+    temporary_span.0.attributes.reserve_exact(
+      (capacity as usize) - temporary_span.0.attributes.capacity(),
+    );
+    attr!(scope, temporary_span, key1, value1);
+    attr!(scope, temporary_span, key2, value2);
+  }
+}
+
+#[allow(clippy::too_many_arguments)]
+#[op2(fast)]
+fn op_otel_span_attribute3<'s>(
+  scope: &mut v8::HandleScope<'s>,
+  state: &mut OpState,
+  #[smi] capacity: u32,
+  key1: v8::Local<'s, v8::Value>,
+  value1: v8::Local<'s, v8::Value>,
+  key2: v8::Local<'s, v8::Value>,
+  value2: v8::Local<'s, v8::Value>,
+  key3: v8::Local<'s, v8::Value>,
+  value3: v8::Local<'s, v8::Value>,
+) {
+  if let Some(temporary_span) = state.try_borrow_mut::<TemporarySpan>() {
+    temporary_span.0.attributes.reserve_exact(
+      (capacity as usize) - temporary_span.0.attributes.capacity(),
+    );
+    attr!(scope, temporary_span, key1, value1);
+    attr!(scope, temporary_span, key2, value2);
+    attr!(scope, temporary_span, key3, value3);
+  }
+}
+
+#[op2(fast)]
+fn op_otel_span_flush(state: &mut OpState) {
+  let Some(temporary_span) = state.try_take::<TemporarySpan>() else {
+    return;
+  };
+
+  let Some(span_processor) = state.try_borrow::<SpanProcessor>() else {
+    return;
+  };
+
+  span_processor.on_end(temporary_span.0);
+}