Changelog

All notable changes, new features, architectural improvements, and deprecations in the Ginboot Framework are documented here.

[Unreleased]

ginboot.New() reads telemetry.enabled and installs tracing, metrics, request IDs and trace-correlated logging, before any route is registered.
Previously the block was parsed and ignored: telemetry only ran if an application called telemetry.Setup and telemetry.Instrument by hand.
Requires a blank import, which is what compiles the plugin in and lets it register itself:
```
import _ "github.com/klass-lk/ginboot/telemetry"
```
Applications that do not import it are unaffected and still do not carry the OpenTelemetry SDK. Configuration that asks for telemetry the binary cannot provide now says so at startup instead of staying silent.

OTEL_EXPORTER_OTLP_ENDPOINT — or the signal-specific ..._TRACES_/_METRICS_/_LOGS_ENDPOINT — turns instrumentation on by itself.
This is for deployments that ship a compiled binary and no config file, where ginboot.yml is not there to be read and telemetry.enabled would be false however the repository has it.
OTEL_SDK_DISABLED=true beats both signals, for a service whose environment names a collector it should not talk to.

Sampling was hardcoded to AlwaysSample, which silently overrode OTEL_TRACES_SAMPLER and OTEL_TRACES_SAMPLER_ARG. A service turning the ratio down to shed load stayed at full volume.
Unset, the SDK now defaults to parentbased_always_on: the same volume as before, but an upstream caller's decision not to sample is respected rather than overridden.

Middleware installed a second time doubled every span, log line and metric for the life of the process. An application that both imports the plugin and calls Instrument itself would have done exactly that.
The first caller wins; later ones do nothing.

Drains buffered telemetry where a process ends deliberately. Not useful on a runtime that is suspended rather than stopped, such as AWS Lambda.

Lambda freezes the execution environment the moment a handler returns, and an export's wall-clock deadline keeps running while it is frozen. A fast handler therefore lost all of its telemetry to context deadline exceeded, not merely some of it.
runtime/lambda now registers as a Lambda internal extension and drains telemetry in the window between the response going out and the environment freezing. Nothing to configure.
Responses are not delayed — Lambda returns the response before extensions finish — but the drain is inside the billed invocation. Bound it with GINBOOT_TELEMETRY_FLUSH_TIMEOUT (default 2s) and watch PostRuntimeExtensionsDuration.
HTTP servers are unaffected: the machinery lives in runtime/lambda, is inert unless AWS_LAMBDA_RUNTIME_API is set, and does not register at all when no telemetry is compiled in. A failed registration leaves the function serving exactly as before.

Introduced unified YAML configuration parsing (ginboot.yml, application.yml, ginboot.yaml, application.yaml).
Config structure supporting server, services, db, and telemetry sections.
Access server configuration anywhere via server.Config().

Automatically loads .env, .env.local, and .env.development files into process environment variables without needing third-party loader boilerplate in main.go.
Added support for 4 environment variable injection syntaxes inside YAML config files:
- ${VAR:default}
- ${VAR}
- env(VAR, default)
- $VAR

Added high-level service communication methods to ginboot.Context:
- ctx.CallService("service-name", path, payload, &response) (synchronous request-reply)
- ctx.CallServiceAsync("service-name", path, payload) (non-blocking fire-and-forget)
Implemented ConfigServiceResolver supporting dynamic endpoint resolution via SERVICE_<NAME>_URL environment variables and Ginboot Cloud UI environment injection.
Automatic OpenTelemetry W3C trace context header propagation (traceparent, tracestate) across downstream service calls.

Added generic .air.toml configuration generator (EnsureAirConfig).
Ginboot applications running in debug mode automatically ensure .air.toml is created in the project root watching .go, .yml, .yaml, and .env files for seamless live hot-reloading.