fix(grpc): resilient SwooleGrpcTransport — mutex, retry, reconnect and PHP 8.2 compat

[lucas-angeli-gimenes]

Description

Fixes three production bugs in SwooleGrpcTransport reported via error logs, plus a suite of structural improvements identified during code review.

Bug fixes

Error	Root cause	Fix
Broken pipe — batch lost	Stale HTTP/2 connection not detected; no retry	Retry loop on send failure (attemptSend): reset client + reconnect up to maxRetries
Creation of dynamic property ... deprecated — recv aborted	Swoole sets $serverLastStreamId dynamically; Hyperf's ErrorExceptionHandler converts E_DEPRECATED → ErrorException	@$client->recv() suppresses the notice before Hyperf's handler sees it
Race condition — concurrent coroutines corrupt shared $client	No synchronisation on send()	Channel(1) as a coroutine-safe mutex; shutdown() closes the channel to unblock waiting coroutines without deadlock

Recv failures are not retried intentionally: once send() succeeds, delivery is uncertain and retrying DELTA metric exports risks duplication.

Structural improvements

• retryDelay / maxRetries now wired from factory → transport constructor (previously silently discarded)
• Endpoint fallback (http://localhost:4317) added to Trace and Metric gRPC factories
• 'application/x-protobuf' string literals replaced with ContentTypes::PROTOBUF constant
• getClient() now closes stale (disconnected) clients before reconnecting
• resetClient() closes the socket before nulling the reference (avoids leaking dead sockets)
• Compression type validated in factory — prevents compressed_flag=1 with uncompressed payload
• grpc-status cast to int before comparison (more robust against whitespace / non-conformant servers)
• attemptSend extracted into doRequest to reduce cyclomatic complexity below PHPMD threshold
• gRPC framing comment added to packMessage

Also in this PR

• feat(shutdown): flush OTel on AfterHandle / AfterExecute events so CLI commands flush spans on exit
• style: fix method ordering in ChannelBatchSpanProcessor per PHP-CS-Fixer rule

Type of change

• Bug fix
• Performance/Refactor

Checklist

• Title follows Conventional Commits
• Tests added/updated
• composer test passes locally (184 tests, 461 assertions)
• Documentation updated (README/Docs)
• No breaking changes

Related issues

#23

[Copilot]

Pull request overview

Improves reliability and PHP 8.2 compatibility of the Swoole-based OTLP gRPC transport, and ensures telemetry is flushed on CLI shutdown events.

Changes:

• Add coroutine-safe send serialization plus retry/reconnect logic to SwooleGrpcTransport, and wire retryDelay/maxRetries through the factory.
• Add default OTLP gRPC endpoints in trace/metric factories and replace protobuf content-type string literals with ContentTypes::PROTOBUF.
• Flush/shutdown OTel providers on CLI command lifecycle events, plus associated unit test updates.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/Transport/SwooleGrpcTransport.php	Adds mutex-based serialization and retry/reconnect logic; refactors request execution.
src/Transport/SwooleGrpcTransportFactory.php	Validates compression type and forwards retry parameters to the transport.
src/Listener/OtelShutdownListener.php	Extends listener to CLI command events to trigger provider shutdown/flush.
src/SpanProcessor/ChannelBatchSpanProcessor.php	Reorders methods to satisfy style/tooling rules.
src/Factory/Trace/Exporter/OtlpGrpcTraceExporterFactory.php	Adds default endpoint fallback and uses ContentTypes::PROTOBUF.
src/Factory/Metric/Exporter/OtlpGrpcMetricExporterFactory.php	Adds default endpoint fallback and uses ContentTypes::PROTOBUF.
src/Factory/Log/Exporter/OtlpGrpcLogExporterFactory.php	Uses ContentTypes::PROTOBUF (and already applies default endpoint fallback).
tests/Unit/Transport/SwooleGrpcTransportFactoryTest.php	Adds coverage for retry parameter wiring and unsupported compression validation.
tests/Unit/Listener/OtelShutdownListenerTest.php	Updates expected listened events to include CLI command lifecycle events.
tests/Unit/Factory/Trace/Exporter/OtlpGrpcTraceExporterFactoryTest.php	Adds test ensuring factory works with default endpoint when options are empty.
tests/Unit/Factory/Metric/Exporter/OtlpGrpcMetricExporterFactoryTest.php	Adds test ensuring factory works with default endpoint when options are empty.

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[Copilot]

retryDelay/maxRetries are now forwarded into the transport, but there’s no validation that they’re non-negative. A negative maxRetries will cause the retry loop to never run (no send attempt), and a negative retryDelay could lead to confusing behavior. Consider validating (and rejecting) negative values here before constructing the transport.

[Copilot]

The retry loop condition for ($attempt = 0; $attempt <= $this->maxRetries; ++$attempt) will execute zero times if maxRetries is negative, resulting in an immediate Unknown transport error after retries without any send attempt. Consider normalizing maxRetries to >= 0 (e.g., in the constructor) or throwing on invalid values to avoid silent misconfiguration.

[Copilot]

Subscribing to both AfterHandle and AfterExecute means process() will run twice for a single CLI command in environments where both events are dispatched, causing duplicate shutdown attempts. Consider guarding so shutdown runs only once (e.g., track a local shutdownCalled flag) or subscribe to only one of these events if possible.