feat(config): add resource and propagator creation from declarative config

CHANGELOG.md

@@ -12,6 +12,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- `opentelemetry-sdk`: Add `create_resource` and `create_propagator`/`configure_propagator` to declarative file configuration, enabling Resource and propagator instantiation from config files without reading env vars
+  ([#4979](https://github.com/open-telemetry/opentelemetry-python/pull/4979))
 - `opentelemetry-sdk`: Add file configuration support with YAML/JSON loading, environment variable substitution, and schema validation against the vendored OTel config JSON schema
   ([#4898](https://github.com/open-telemetry/opentelemetry-python/pull/4898))
 - Fix intermittent CI failures in `getting-started` and `tracecontext` jobs caused by GitHub git CDN SHA propagation lag by installing contrib packages from the already-checked-out local copy instead of a second git clone

opentelemetry-sdk/src/opentelemetry/sdk/_configuration/_exceptions.py

@@ -0,0 +1,25 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+class ConfigurationError(Exception):
+    """Raised when configuration loading, parsing, validation, or instantiation fails.
+
+    This includes errors from:
+    - File not found or inaccessible
+    - Invalid YAML/JSON syntax
+    - Schema validation failures
+    - Environment variable substitution errors
+    - Missing required SDK extensions (e.g., propagator packages not installed)
+    """

opentelemetry-sdk/src/opentelemetry/sdk/_configuration/_propagator.py

@@ -0,0 +1,125 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+import logging
+from typing import Optional
+
+from opentelemetry.baggage.propagation import W3CBaggagePropagator
+from opentelemetry.propagate import set_global_textmap
+from opentelemetry.propagators.composite import CompositePropagator
+from opentelemetry.propagators.textmap import TextMapPropagator
+from opentelemetry.sdk._configuration._exceptions import ConfigurationError
+from opentelemetry.sdk._configuration.models import (
+    Propagator as PropagatorConfig,
+)
+from opentelemetry.sdk._configuration.models import (
+    TextMapPropagator as TextMapPropagatorConfig,
+)
+from opentelemetry.trace.propagation.tracecontext import (
+    TraceContextTextMapPropagator,
+)
+from opentelemetry.util._importlib_metadata import entry_points
+
+_logger = logging.getLogger(__name__)
+
+
+def _load_entry_point_propagator(name: str) -> TextMapPropagator:
+    """Load a propagator by name from the opentelemetry_propagator entry point group."""
+    try:
+        eps = list(entry_points(group="opentelemetry_propagator", name=name))
+        if not eps:
+            raise ConfigurationError(
+                f"Propagator '{name}' not found. "
+                "It may not be installed or may be misspelled."
+            )
+        return eps[0].load()()
+    except ConfigurationError:
+        raise
+    except Exception as exc:
+        raise ConfigurationError(
+            f"Failed to load propagator '{name}': {exc}"
+        ) from exc
+
+
+def _propagators_from_textmap_config(
+    config: TextMapPropagatorConfig,
+) -> list[TextMapPropagator]:
+    """Resolve a single TextMapPropagator config entry to a list of propagators."""
+    result: list[TextMapPropagator] = []
+    if config.tracecontext is not None:
+        result.append(TraceContextTextMapPropagator())
+    if config.baggage is not None:
+        result.append(W3CBaggagePropagator())
+    if config.b3 is not None:
+        result.append(_load_entry_point_propagator("b3"))
+    if config.b3multi is not None:
+        result.append(_load_entry_point_propagator("b3multi"))
+    return result
+
+
+def create_propagator(
+    config: Optional[PropagatorConfig],
+) -> CompositePropagator:
+    """Create a CompositePropagator from declarative config.
+
+    If config is None or has no propagators defined, returns an empty
+    CompositePropagator (no-op), ensuring "what you see is what you get"
+    semantics — the env-var-based default propagators are not used.
+
+    Args:
+        config: Propagator config from the parsed config file, or None.
+
+    Returns:
+        A CompositePropagator wrapping all configured propagators.
+    """
+    if config is None:
+        return CompositePropagator([])
+
+    propagators: list[TextMapPropagator] = []
+    seen_types: set[type] = set()
+
+    def _add_deduped(propagator: TextMapPropagator) -> None:
+        if type(propagator) not in seen_types:
+            seen_types.add(type(propagator))
+            propagators.append(propagator)
+
+    # Process structured composite list
+    if config.composite:
+        for entry in config.composite:
+            for propagator in _propagators_from_textmap_config(entry):
+                _add_deduped(propagator)
+
+    # Process composite_list (comma-separated propagator names via entry_points)
+    if config.composite_list:
+        for name in config.composite_list.split(","):
+            name = name.strip()
+            if not name or name.lower() == "none":
+                continue
+            _add_deduped(_load_entry_point_propagator(name))
+
+    return CompositePropagator(propagators)
+
+
+def configure_propagator(config: Optional[PropagatorConfig]) -> None:
+    """Configure the global text map propagator from declarative config.
+
+    Always calls set_global_textmap to override any defaults (including the
+    env-var-based tracecontext+baggage default set by the SDK).
+
+    Args:
+        config: Propagator config from the parsed config file, or None.
+    """
+    set_global_textmap(create_propagator(config))

opentelemetry-sdk/src/opentelemetry/sdk/_configuration/_resource.py

@@ -0,0 +1,150 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+import logging
+from typing import Optional
+from urllib import parse
+
+from opentelemetry.sdk._configuration.models import (
+    AttributeNameValue,
+    AttributeType,
+)
+from opentelemetry.sdk._configuration.models import Resource as ResourceConfig
+from opentelemetry.sdk.resources import (
+    _OPENTELEMETRY_SDK_VERSION,
+    SERVICE_NAME,
+    TELEMETRY_SDK_LANGUAGE,
+    TELEMETRY_SDK_NAME,
+    TELEMETRY_SDK_VERSION,
+    Resource,
+)
+
+_logger = logging.getLogger(__name__)
+
+# Dispatch table for scalar type coercions
+_SCALAR_COERCIONS = {
+    AttributeType.string: str,
+    AttributeType.int: int,
+    AttributeType.double: float,
+}
+
+# Dispatch table for array type coercions
+_ARRAY_COERCIONS = {
+    AttributeType.string_array: str,
+    AttributeType.bool_array: bool,
+    AttributeType.int_array: int,
+    AttributeType.double_array: float,
+}
+
+
+def _coerce_bool(value: object) -> bool:
+    if isinstance(value, str):
+        return value.lower() not in ("false", "0", "")
+    return bool(value)
+
+
+def _coerce_attribute_value(attr: AttributeNameValue) -> object:
+    """Coerce an attribute value to the correct Python type based on AttributeType."""
+    value = attr.value
+    attr_type = attr.type
+
+    if attr_type is None:
+        return value
+    if attr_type == AttributeType.bool:
+        return _coerce_bool(value)
+    scalar_coercer = _SCALAR_COERCIONS.get(attr_type)
+    if scalar_coercer is not None:
+        return scalar_coercer(value)  # type: ignore[arg-type]
+    array_coercer = _ARRAY_COERCIONS.get(attr_type)
+    if array_coercer is not None:
+        return [array_coercer(item) for item in value]  # type: ignore[union-attr,arg-type]
+    return value
+
+
+def _parse_attributes_list(attributes_list: str) -> dict[str, str]:
+    """Parse a comma-separated key=value string into a dict.
+
+    Format is the same as OTEL_RESOURCE_ATTRIBUTES: key=value,key=value
+    Values are always strings (no type coercion).
+    """
+    result: dict[str, str] = {}
+    for item in attributes_list.split(","):
+        item = item.strip()
+        if not item:
+            continue
+        if "=" not in item:
+            _logger.warning(
+                "Invalid resource attribute pair in attributes_list: %s",
+                item,
+            )
+            continue
+        key, value = item.split("=", maxsplit=1)
+        result[key.strip()] = parse.unquote(value.strip())
+    return result
+
+
+def _sdk_default_attributes() -> dict[str, str]:
+    """Return the SDK telemetry attributes (equivalent to Java's Resource.getDefault())."""
+    return {
+        TELEMETRY_SDK_LANGUAGE: "python",
+        TELEMETRY_SDK_NAME: "opentelemetry",
+        TELEMETRY_SDK_VERSION: _OPENTELEMETRY_SDK_VERSION,
+    }
+
+
+def create_resource(config: Optional[ResourceConfig]) -> Resource:
+    """Create an SDK Resource from declarative config.
+
+    Does NOT read OTEL_RESOURCE_ATTRIBUTES or run any resource detectors.
+    Starts from SDK telemetry defaults (telemetry.sdk.*) and merges config
+    attributes on top, matching Java SDK behavior.
+
+    Args:
+        config: Resource config from the parsed config file, or None.
+
+    Returns:
+        A Resource with SDK defaults merged with any config-specified attributes.
+    """
+    base = Resource(_sdk_default_attributes())
+
+    if config is None:
+        service_resource = Resource({SERVICE_NAME: "unknown_service"})
+        return base.merge(service_resource)
+
+    # Build attributes from config.attributes list
+    config_attrs: dict[str, object] = {}
+    if config.attributes:
+        for attr in config.attributes:
+            config_attrs[attr.name] = _coerce_attribute_value(attr)
+
+    # Parse attributes_list (key=value,key=value string format)
+    if config.attributes_list:
+        list_attrs = _parse_attributes_list(config.attributes_list)
+        # attributes_list entries do not override explicit attributes
+        for attr_key, attr_val in list_attrs.items():
+            if attr_key not in config_attrs:
+                config_attrs[attr_key] = attr_val
+
+    schema_url = config.schema_url
+
+    config_resource = Resource(config_attrs, schema_url)  # type: ignore[arg-type]
+    result = base.merge(config_resource)
+
+    # Add default service.name if not specified (matches Java SDK behavior)
+    if not result.attributes.get(SERVICE_NAME):
+        result = result.merge(Resource({SERVICE_NAME: "unknown_service"}))
+
+    return result

opentelemetry-sdk/src/opentelemetry/sdk/_configuration/file/__init__.py

@@ -24,6 +24,11 @@
     '1.0'
 """
 
+from opentelemetry.sdk._configuration._propagator import (
+    configure_propagator,
+    create_propagator,
+)
+from opentelemetry.sdk._configuration._resource import create_resource
 from opentelemetry.sdk._configuration.file._env_substitution import (
     EnvSubstitutionError,
     substitute_env_vars,
@@ -38,4 +43,7 @@
     "substitute_env_vars",
     "ConfigurationError",
     "EnvSubstitutionError",
+    "create_resource",
+    "create_propagator",
+    "configure_propagator",
 ]

opentelemetry-sdk/src/opentelemetry/sdk/_configuration/file/_loader.py

@@ -20,6 +20,7 @@
 from pathlib import Path
 from typing import Any
 
+from opentelemetry.sdk._configuration._exceptions import ConfigurationError
 from opentelemetry.sdk._configuration.file._env_substitution import (
     substitute_env_vars,
 )
@@ -59,15 +60,8 @@ def _get_schema() -> dict:
 _logger = logging.getLogger(__name__)
 
 
-class ConfigurationError(Exception):
-    """Raised when configuration file loading, parsing, or validation fails.
-
-    This includes errors from:
-    - File not found or inaccessible
-    - Invalid YAML/JSON syntax
-    - Schema validation failures
-    - Environment variable substitution errors
-    """
+# Re-export for backwards compatibility
+__all__ = ["ConfigurationError", "load_config_file"]
 
 
 def load_config_file(file_path: str) -> OpenTelemetryConfiguration: