oss_25_declarative_config_configprovider_create

[ocelotl]

Declarative config: add a stateless create(model)->providers alongside configure_sdk(), plus a ConfigProvider/ConfigProperties view over the .instrumentation node (Linear OSS-25, finding L8).

Branch / worktree: oss_25_declarative_config_configprovider_create

Linear issue: https://linear.app/dash0/issue/OSS-25/l8-declarative-config-no-configproviderconfigproperties-api-no-pure

[ocelotl]

🔒 Internal (dash0) — not for upstream.

• Linear: https://linear.app/dash0/issue/OSS-25/l8-declarative-config-no-configproviderconfigproperties-api-no-pure (finding L8)
• Slug/branch/worktree: oss_25_declarative_config_configprovider_create
• Commit: 1834b27a8 · PR: oss_25_declarative_config_configprovider_create #45
• Validation: opentelemetry-configuration suite 392 passed; scope package + changelog.
• Reviewer notes: (1) rewrote 3 pre-existing TestConfigureSdk tests that asserted the old per-signal configure_* delegation (globals are now set directly inside configure_sdk via create()). (2) touches _sdk.py — same-package overlap with OSS-24/PR oss_24_declarative_config_present_null_defaults #34 and OSS-26/PR oss_26_declarative_config_env_substitution #36; merge sequentially.

[ocelotl]

📣 Public-facing draft — to be opened upstream in open-telemetry/opentelemetry-python. No internal references; copy verbatim.

Title: Declarative config: add stateless create(model) and ConfigProvider/ConfigProperties for instrumentation config

The opentelemetry-configuration package exposes only the global-mutating configure_sdk() (src/opentelemetry/configuration/_sdk.py). There is no way to build the SDK providers from a parsed model without installing them as process globals, and no read view over the parsed instrumentation node for instrumentation libraries.

Two gaps versus the specification:

1. No pure builder. configure_sdk() both builds and installs globals, so embedders/tests cannot obtain providers without side effects. The spec's sdk.md and Java's DeclarativeConfiguration separate parse() (YAML → model) from create(model) (model → providers).
2. No ConfigProvider / ConfigProperties. configuration/api.md (Stable) defines a ConfigProvider returning a ConfigProperties read view over the .instrumentation node, with type-safe accessors (string/bool/int/double, sub-config, lists, key set) returning null on missing key / type mismatch (Java: DeclarativeConfigProperties). Python exposes neither.

Proposed fix

Add a pure create(model) -> providers that returns built providers without mutating globals, and have configure_sdk() reuse it (create + set globals). Add a ConfigProperties typed read view over the parsed instrumentation node and a global ConfigProvider that makes it retrievable.