LiquidRazor POSIX Runtime

liquidrazor/posix-runtime is a small PHP 8.3+ library that provides POSIX runtime primitives for isolated worker execution.

It is transport-agnostic process-control infrastructure for the LiquidRazor micro-kernel lifecycle. It does not implement HTTP, CLI, queue, gRPC, routing, DI, logging, scheduling, or daemon management.

Requirements

• PHP 8.3+
• ext-posix
• ext-pcntl

Missing required extensions are treated as runtime failures. The library does not silently degrade to PID-only supervision.

What It Ships

Current public surface:

• immutable value objects under include/Value
• enums under include/Enum
• typed exceptions under include/Exception
• public contracts under include/Contract
• a thin public facade: LiquidRazor\PosixRuntime\PosixRuntime

Current runtime behavior:

• worker identity generation
• worker process metadata before and after fork
• centralized POSIX/PCNTL adapter boundary
• raw wait-status interpretation
• signal handler registration
• pending-signal dispatch
• child execution wrapping
• parent-side worker supervision
• graceful shutdown requests
• forced termination escalation

What It Does Not Ship

This library does not implement:

• transport kernels
• framework bootstrapping
• event manager infrastructure
• process event catalogs
• service containers
• schedulers
• external process-manager replacement behavior

Higher-level kernels are expected to plug into the runtime lifecycle exposed here.

Public API

The main entry point is LiquidRazor\PosixRuntime\PosixRuntime.

It currently exposes:

• capabilityStatus(): RuntimeCapabilityStatus
• assertAvailable(): void
• run(WorkerExecutionRequest $request): SupervisionResult
• shutdown(WorkerProcessMetadata $metadata, ShutdownRequest $request): SupervisionResult

Typical value types involved in public calls:

• WorkerId
• WorkerIdentity
• ProcessId
• WorkerProcessMetadata
• WorkerExecutionRequest
• WorkerExecutionResult
• WorkerExitStatus
• ShutdownRequest
• SupervisionResult

Example

<?php

declare(strict_types=1);

use LiquidRazor\PosixRuntime\Include\Value\ProcessId;
use LiquidRazor\PosixRuntime\Include\Value\WorkerExecutionRequest;
use LiquidRazor\PosixRuntime\Include\Value\WorkerId;
use LiquidRazor\PosixRuntime\Include\Value\WorkerIdentity;
use LiquidRazor\PosixRuntime\Include\Value\WorkerProcessMetadata;
use LiquidRazor\PosixRuntime\PosixRuntime;

$runtime = new PosixRuntime();

$request = new WorkerExecutionRequest(
    WorkerProcessMetadata::prepare(
        new WorkerIdentity(new WorkerId('example-worker'), 'example-worker'),
        new ProcessId(posix_getpid()),
    ),
    static fn (): int => 0,
);

$result = $runtime->run($request);

SupervisionResult contains:

• the final WorkerExecutionResult
• an optional ShutdownRequest
• a forcedTermination flag

Lifecycle Model

The implemented lifecycle is:

Parent prepares worker metadata
Parent forks worker

Parent path:
    receive child PID
    supervise with waitpid()
    dispatch pending signals
    interpret final status
    return structured result

Child path:
    install child-local signal handlers
    execute callback
    exit with explicit code

The runtime currently models these worker states:

• Prepared
• Spawned
• Running
• Finished
• Crashed
• ShutdownRequested
• Terminated
• ForcedTermination

Termination reasons are modeled separately:

• Completed
• NonZeroExit
• Signal
• ShutdownRequested
• ForcedTermination
• Crash

Signal Handling

The runtime currently supports explicit registration and dispatch of:

• SIGTERM
• SIGINT
• SIGQUIT when supported by the platform
• SIGCHLD

Signal behavior is explicit:

• handlers are registered through dedicated services
• pending signals are dispatched deliberately
• child-local termination handlers re-signal with the default handler so parent supervision sees signal termination correctly

Supervision And Shutdown

Parent-side supervision is driven by waitpid() through the adapter layer.

Implemented outcomes include:

• successful completion
• non-zero exit
• signal termination
• shutdown-requested completion
• forced termination

Shutdown coordination currently supports:

1. send graceful signal
2. wait until timeout
3. escalate to forced signal when required

Failure Model

The library uses typed exceptions for meaningful runtime failures, including:

• MissingPosixExtension
• MissingPcntlExtension
• RuntimeUnavailable
• ForkFailed
• SignalRegistrationFailed
• InvalidWorkerStateTransition
• WorkerExecutionFailed
• WorkerCrashed
• WorkerTerminatedBySignal
• WaitOperationFailed
• ShutdownTimeoutExceeded
• ForcedTerminationFailed

Structured results are used for normal process outcomes. Exceptions are reserved for unavailable runtime capabilities or failed control operations.

Directory Layout

include/
  Contract/
  Enum/
  Exception/
  Value/

lib/
  Runtime/
  Signal/
  Supervision/

src/
  PosixRuntime.php

tests/

Dependency direction is strict:

include <- lib <- src

Testing

The current PHPUnit suite covers:

• value-model invariants
• capability detection
• adapter failure mapping
• exit-status interpretation
• signal registration and dispatch
• spawn and child execution
• parent-side supervision
• graceful shutdown
• forced termination escalation
• public facade wiring

Process tests skip cleanly when POSIX support is unavailable and include defensive child cleanup to avoid zombie processes.

License

MIT