Use SeededRandomIdGenerator by default to prevent interference from…

… `random.seed` (#457)

logfire/_internal/config.py

@@ -46,7 +46,7 @@
 from opentelemetry.sdk.resources import Resource
 from opentelemetry.sdk.trace import SpanProcessor, TracerProvider as SDKTracerProvider
 from opentelemetry.sdk.trace.export import BatchSpanProcessor, SimpleSpanProcessor
-from opentelemetry.sdk.trace.id_generator import IdGenerator, RandomIdGenerator
+from opentelemetry.sdk.trace.id_generator import IdGenerator
 from opentelemetry.sdk.trace.sampling import ParentBasedTraceIdRatio, Sampler
 from opentelemetry.semconv.resource import ResourceAttributes
 from rich.console import Console
@@ -83,7 +83,14 @@
 from .scrubbing import NOOP_SCRUBBER, BaseScrubber, Scrubber, ScrubbingOptions
 from .stack_info import warn_at_user_stacklevel
 from .tracer import PendingSpanProcessor, ProxyTracerProvider
-from .utils import UnexpectedResponse, ensure_data_dir_exists, get_version, read_toml_file, suppress_instrumentation
+from .utils import (
+    SeededRandomIdGenerator,
+    UnexpectedResponse,
+    ensure_data_dir_exists,
+    get_version,
+    read_toml_file,
+    suppress_instrumentation,
+)
 
 if TYPE_CHECKING:
     from .main import FastLogfireSpan, LogfireSpan
@@ -136,8 +143,11 @@ class AdvancedOptions:
     base_url: str = 'https://logfire-api.pydantic.dev'
     """Root URL for the Logfire API."""
 
-    id_generator: IdGenerator = dataclasses.field(default_factory=RandomIdGenerator)
-    """Generator for trace and span IDs."""
+    id_generator: IdGenerator = dataclasses.field(default_factory=lambda: SeededRandomIdGenerator(None))
+    """Generator for trace and span IDs.
+
+    The default generates random IDs and is unaffected by calls to `random.seed()`.
+    """
 
     ns_timestamp_generator: Callable[[], int] = time.time_ns
     """Generator for nanosecond start and end timestamps of spans."""

logfire/_internal/utils.py

@@ -4,15 +4,18 @@
 import json
 import logging
 import os
+import random
 import sys
 from contextlib import contextmanager
+from dataclasses import dataclass
 from pathlib import Path
 from types import TracebackType
 from typing import TYPE_CHECKING, Any, Dict, List, Mapping, Sequence, Tuple, TypedDict, TypeVar, Union
 
 from opentelemetry import context, trace as trace_api
 from opentelemetry.sdk.resources import Resource
 from opentelemetry.sdk.trace import Event, ReadableSpan
+from opentelemetry.sdk.trace.id_generator import IdGenerator
 from opentelemetry.sdk.util.instrumentation import InstrumentationScope
 from opentelemetry.trace.status import Status
 from opentelemetry.util import types as otel_types
@@ -348,3 +351,33 @@ def maybe_capture_server_headers(capture: bool):
 
 def is_asgi_send_receive_span_name(name: str) -> bool:
     return name.endswith((' http send', ' http receive', ' websocket send', ' websocket receive'))
+
+
+@dataclass(repr=True)
+class SeededRandomIdGenerator(IdGenerator):
+    """Generate random span/trace IDs from a seed for deterministic tests.
+
+    Similar to RandomIdGenerator from OpenTelemetry, but with a seed.
+    Set the seed to None for non-deterministic randomness.
+    In that case the difference from RandomIdGenerator is that it's not affected by `random.seed(...)`.
+
+    Trace IDs are 128-bit integers.
+    Span IDs are 64-bit integers.
+    """
+
+    seed: int | None = 0
+
+    def __post_init__(self) -> None:
+        self.random = random.Random(self.seed)
+
+    def generate_span_id(self) -> int:
+        span_id = self.random.getrandbits(64)
+        while span_id == trace_api.INVALID_SPAN_ID:  # pragma: no cover
+            span_id = self.random.getrandbits(64)
+        return span_id
+
+    def generate_trace_id(self) -> int:
+        trace_id = self.random.getrandbits(128)
+        while trace_id == trace_api.INVALID_TRACE_ID:  # pragma: no cover
+            trace_id = self.random.getrandbits(128)
+        return trace_id

logfire/testing.py

@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import random
 from dataclasses import dataclass
 
 import pytest
@@ -14,6 +13,7 @@
 
 from ._internal.constants import ONE_SECOND_IN_NANOSECONDS
 from ._internal.exporters.test import TestExporter
+from ._internal.utils import SeededRandomIdGenerator
 
 __all__ = [
     'capfire',
@@ -56,28 +56,6 @@ def generate_trace_id(self) -> int:
         return self.trace_id_counter
 
 
-@dataclass(repr=True)
-class SeededRandomIdGenerator(IdGenerator):
-    """Generate random span/trace IDs from a random seed for deterministic tests.
-
-    Trace IDs are 64-bit integers.
-    Span IDs are 32-bit integers.
-    """
-
-    seed: int = 0
-
-    def __post_init__(self) -> None:
-        self.random = random.Random(self.seed)
-
-    def generate_span_id(self) -> int:
-        """Generates a random span id."""
-        return self.random.getrandbits(64)
-
-    def generate_trace_id(self) -> int:
-        """Generates a random trace id."""
-        return self.random.getrandbits(128)
-
-
 # Making this a dataclass causes errors in the process pool end-to-end tests
 class TimeGenerator:
     """Generate incrementing timestamps for testing.