feat: introduce rust_tracing integration (#3717)

Introduce a new integration that allows traces to descend into code in Rust native extensions by hooking into Rust's popular `tracing` framework. it relies on the Rust native extension using [`pyo3-python-tracing-subscriber`](https://crates.io/crates/pyo3-python-tracing-subscriber), a crate i recently published under Sentry, to expose a way for the Python SDK to hook into `tracing`.

in this screenshot, the transaction was started in Python but the rest of the span tree reflects the structure and performance of a naive fibonacci generator in Rust: https://github.com/user-attachments/assets/ae2caff6-1842-45d0-a604-2f3b6305f330

---------

Co-authored-by: Anton Pirker <[email protected]>

sentry_sdk/integrations/rust_tracing.py

@@ -0,0 +1,274 @@
+"""
+This integration ingests tracing data from native extensions written in Rust.
+
+Using it requires additional setup on the Rust side to accept a
+`RustTracingLayer` Python object and register it with the `tracing-subscriber`
+using an adapter from the `pyo3-python-tracing-subscriber` crate. For example:
+```rust
+#[pyfunction]
+pub fn initialize_tracing(py_impl: Bound<'_, PyAny>) {
+    tracing_subscriber::registry()
+        .with(pyo3_python_tracing_subscriber::PythonCallbackLayerBridge::new(py_impl))
+        .init();
+}
+```
+
+Usage in Python would then look like:
+```
+sentry_sdk.init(
+    dsn=sentry_dsn,
+    integrations=[
+        RustTracingIntegration(
+            "demo_rust_extension",
+            demo_rust_extension.initialize_tracing,
+            event_type_mapping=event_type_mapping,
+        )
+    ],
+)
+```
+
+Each native extension requires its own integration.
+"""
+
+import json
+from enum import Enum, auto
+from typing import Any, Callable, Dict, Tuple, Optional
+
+import sentry_sdk
+from sentry_sdk.integrations import Integration
+from sentry_sdk.scope import should_send_default_pii
+from sentry_sdk.tracing import Span as SentrySpan
+from sentry_sdk.utils import SENSITIVE_DATA_SUBSTITUTE
+
+TraceState = Optional[Tuple[Optional[SentrySpan], SentrySpan]]
+
+
+class RustTracingLevel(Enum):
+    Trace: str = "TRACE"
+    Debug: str = "DEBUG"
+    Info: str = "INFO"
+    Warn: str = "WARN"
+    Error: str = "ERROR"
+
+
+class EventTypeMapping(Enum):
+    Ignore = auto()
+    Exc = auto()
+    Breadcrumb = auto()
+    Event = auto()
+
+
+def tracing_level_to_sentry_level(level):
+    # type: (str) -> sentry_sdk._types.LogLevelStr
+    level = RustTracingLevel(level)
+    if level in (RustTracingLevel.Trace, RustTracingLevel.Debug):
+        return "debug"
+    elif level == RustTracingLevel.Info:
+        return "info"
+    elif level == RustTracingLevel.Warn:
+        return "warning"
+    elif level == RustTracingLevel.Error:
+        return "error"
+    else:
+        # Better this than crashing
+        return "info"
+
+
+def extract_contexts(event: Dict[str, Any]) -> Dict[str, Any]:
+    metadata = event.get("metadata", {})
+    contexts = {}
+
+    location = {}
+    for field in ["module_path", "file", "line"]:
+        if field in metadata:
+            location[field] = metadata[field]
+    if len(location) > 0:
+        contexts["rust_tracing_location"] = location
+
+    fields = {}
+    for field in metadata.get("fields", []):
+        fields[field] = event.get(field)
+    if len(fields) > 0:
+        contexts["rust_tracing_fields"] = fields
+
+    return contexts
+
+
+def process_event(event: Dict[str, Any]) -> None:
+    metadata = event.get("metadata", {})
+
+    logger = metadata.get("target")
+    level = tracing_level_to_sentry_level(metadata.get("level"))
+    message = event.get("message")  # type: sentry_sdk._types.Any
+    contexts = extract_contexts(event)
+
+    sentry_event = {
+        "logger": logger,
+        "level": level,
+        "message": message,
+        "contexts": contexts,
+    }  # type: sentry_sdk._types.Event
+
+    sentry_sdk.capture_event(sentry_event)
+
+
+def process_exception(event: Dict[str, Any]) -> None:
+    process_event(event)
+
+
+def process_breadcrumb(event: Dict[str, Any]) -> None:
+    level = tracing_level_to_sentry_level(event.get("metadata", {}).get("level"))
+    message = event.get("message")
+
+    sentry_sdk.add_breadcrumb(level=level, message=message)
+
+
+def default_span_filter(metadata: Dict[str, Any]) -> bool:
+    return RustTracingLevel(metadata.get("level")) in (
+        RustTracingLevel.Error,
+        RustTracingLevel.Warn,
+        RustTracingLevel.Info,
+    )
+
+
+def default_event_type_mapping(metadata: Dict[str, Any]) -> EventTypeMapping:
+    level = RustTracingLevel(metadata.get("level"))
+    if level == RustTracingLevel.Error:
+        return EventTypeMapping.Exc
+    elif level in (RustTracingLevel.Warn, RustTracingLevel.Info):
+        return EventTypeMapping.Breadcrumb
+    elif level in (RustTracingLevel.Debug, RustTracingLevel.Trace):
+        return EventTypeMapping.Ignore
+    else:
+        return EventTypeMapping.Ignore
+
+
+class RustTracingLayer:
+    def __init__(
+        self,
+        origin: str,
+        event_type_mapping: Callable[
+            [Dict[str, Any]], EventTypeMapping
+        ] = default_event_type_mapping,
+        span_filter: Callable[[Dict[str, Any]], bool] = default_span_filter,
+        send_sensitive_data: Optional[bool] = None,
+    ):
+        self.origin = origin
+        self.event_type_mapping = event_type_mapping
+        self.span_filter = span_filter
+        self.send_sensitive_data = send_sensitive_data
+
+    def on_event(self, event: str, _span_state: TraceState) -> None:
+        deserialized_event = json.loads(event)
+        metadata = deserialized_event.get("metadata", {})
+
+        event_type = self.event_type_mapping(metadata)
+        if event_type == EventTypeMapping.Ignore:
+            return
+        elif event_type == EventTypeMapping.Exc:
+            process_exception(deserialized_event)
+        elif event_type == EventTypeMapping.Breadcrumb:
+            process_breadcrumb(deserialized_event)
+        elif event_type == EventTypeMapping.Event:
+            process_event(deserialized_event)
+
+    def on_new_span(self, attrs: str, span_id: str) -> TraceState:
+        attrs = json.loads(attrs)
+        metadata = attrs.get("metadata", {})
+
+        if not self.span_filter(metadata):
+            return None
+
+        module_path = metadata.get("module_path")
+        name = metadata.get("name")
+        message = attrs.get("message")
+
+        if message is not None:
+            sentry_span_name = message
+        elif module_path is not None and name is not None:
+            sentry_span_name = f"{module_path}::{name}"  # noqa: E231
+        elif name is not None:
+            sentry_span_name = name
+        else:
+            sentry_span_name = "<unknown>"
+
+        kwargs = {
+            "op": "function",
+            "name": sentry_span_name,
+            "origin": self.origin,
+        }
+
+        scope = sentry_sdk.get_current_scope()
+        parent_sentry_span = scope.span
+        if parent_sentry_span:
+            sentry_span = parent_sentry_span.start_child(**kwargs)
+        else:
+            sentry_span = scope.start_span(**kwargs)
+
+        fields = metadata.get("fields", [])
+        for field in fields:
+            sentry_span.set_data(field, attrs.get(field))
+
+        scope.span = sentry_span
+        return (parent_sentry_span, sentry_span)
+
+    def on_close(self, span_id: str, span_state: TraceState) -> None:
+        if span_state is None:
+            return
+
+        parent_sentry_span, sentry_span = span_state
+        sentry_span.finish()
+        sentry_sdk.get_current_scope().span = parent_sentry_span
+
+    def on_record(self, span_id: str, values: str, span_state: TraceState) -> None:
+        if span_state is None:
+            return
+        _parent_sentry_span, sentry_span = span_state
+
+        send_sensitive_data = (
+            should_send_default_pii()
+            if self.send_sensitive_data is None
+            else self.send_sensitive_data
+        )
+
+        deserialized_values = json.loads(values)
+        for key, value in deserialized_values.items():
+            if send_sensitive_data:
+                sentry_span.set_data(key, value)
+            else:
+                sentry_span.set_data(key, SENSITIVE_DATA_SUBSTITUTE)
+
+
+class RustTracingIntegration(Integration):
+    """
+    Ingests tracing data from a Rust native extension's `tracing` instrumentation.
+
+    If a project uses more than one Rust native extension, each one will need
+    its own instance of `RustTracingIntegration` with an initializer function
+    specific to that extension.
+
+    Since all of the setup for this integration requires instance-specific state
+    which is not available in `setup_once()`, setup instead happens in `__init__()`.
+    """
+
+    def __init__(
+        self,
+        identifier: str,
+        initializer: Callable[[RustTracingLayer], None],
+        event_type_mapping: Callable[
+            [Dict[str, Any]], EventTypeMapping
+        ] = default_event_type_mapping,
+        span_filter: Callable[[Dict[str, Any]], bool] = default_span_filter,
+        send_sensitive_data: Optional[bool] = None,
+    ):
+        self.identifier = identifier
+        origin = f"auto.function.rust_tracing.{identifier}"
+        self.tracing_layer = RustTracingLayer(
+            origin, event_type_mapping, span_filter, send_sensitive_data
+        )
+
+        initializer(self.tracing_layer)
+
+    @staticmethod
+    def setup_once() -> None:
+        pass