Awesome-claude-code create-metrics-collector

Generates Metrics Collector for PHP 8.4. Creates MetricsCollectorInterface, Counter/Gauge/Histogram wrappers, PrometheusMetricsCollector, MetricsMiddleware for RED metrics. Includes unit tests.

install

source · Clone the upstream repo

git clone https://github.com/dykyi-roman/awesome-claude-code

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/dykyi-roman/awesome-claude-code "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/create-metrics-collector" ~/.claude/skills/dykyi-roman-awesome-claude-code-create-metrics-collector && rm -rf "$T"

manifest: skills/create-metrics-collector/SKILL.md

source content

Metrics Collector Generator

Creates metrics collection infrastructure for application observability and monitoring.

When to Use

Scenario	Example
Request monitoring	Track request rate, errors, duration (RED)
Business metrics	Count orders, revenue, active users
Performance profiling	Histogram of response times
Health dashboards	Expose `/metrics` for Prometheus scraping

Component Characteristics

MetricsCollectorInterface

Metrics contract for increment, gauge, histogram operations
Backend-agnostic: swap Prometheus for StatsD or custom
Supports labels for dimensional metrics

Counter

Monotonically increasing metric wrapper
Tracks totals: requests, errors, processed items
Supports labels for per-endpoint counts

Gauge

Point-in-time value metric wrapper
Tracks current state: active connections, queue size
Can increase and decrease

Histogram

Distribution metric wrapper
Tracks request duration, response size
Configurable bucket boundaries

PrometheusMetricsCollector

Prometheus PHP client adapter
Registers counters, gauges, histograms
Thread-safe with shared storage

MetricsMiddleware

PSR-15 middleware collecting RED metrics automatically
Rate: total request count per endpoint
Errors: error count by status code
Duration: response time histogram

MetricsAction

```
/metrics
```
endpoint exposing Prometheus format
Returns
```
text/plain
```
with all registered metrics

NullMetricsCollector

Null Object pattern for testing and development
All operations are no-ops
Drop-in replacement without side effects

Generation Process

Step 1: Generate Core Components

Path:

src/Infrastructure/Metrics/

```
MetricsCollectorInterface.php
```
— Metrics contract
```
Counter.php
```
— Counter metric wrapper
```
Gauge.php
```
— Gauge metric wrapper
```
Histogram.php
```
— Histogram metric wrapper

Step 2: Generate Implementations

Path:

src/Infrastructure/Metrics/

```
PrometheusMetricsCollector.php
```
— Prometheus adapter
```
NullMetricsCollector.php
```
— Null Object for testing

Step 3: Generate HTTP Components

Path:

src/Infrastructure/Metrics/

```
MetricsMiddleware.php
```
— PSR-15 RED metrics middleware
```
MetricsAction.php
```
—
```
/metrics
```
endpoint action

Step 4: Generate Tests

```
NullMetricsCollectorTest.php
```
— Null object behavior tests
```
MetricsMiddlewareTest.php
```
— Middleware metrics tests

File Placement

Component	Path
All Classes	`src/Infrastructure/Metrics/`
Unit Tests	`tests/Unit/Infrastructure/Metrics/`

Naming Conventions

Component	Pattern	Example
Interface	`MetricsCollectorInterface`	`MetricsCollectorInterface`
Counter	`Counter`	`Counter`
Gauge	`Gauge`	`Gauge`
Histogram	`Histogram`	`Histogram`
Prometheus	`PrometheusMetricsCollector`	`PrometheusMetricsCollector`
Null Object	`NullMetricsCollector`	`NullMetricsCollector`
Middleware	`MetricsMiddleware`	`MetricsMiddleware`
Action	`MetricsAction`	`MetricsAction`
Test	`{ClassName}Test`	`MetricsMiddlewareTest`

Quick Template Reference

MetricsCollectorInterface

interface MetricsCollectorInterface
{
    /** @param array<string, string> $labels */
    public function increment(string $name, array $labels = [], float $value = 1.0): void;

    /** @param array<string, string> $labels */
    public function gauge(string $name, float $value, array $labels = []): void;

    /** @param array<string, string> $labels */
    public function histogram(string $name, float $value, array $labels = []): void;
}

MetricsMiddleware

final readonly class MetricsMiddleware implements MiddlewareInterface
{
    public function process(
        ServerRequestInterface $request,
        RequestHandlerInterface $handler
    ): ResponseInterface;
}

NullMetricsCollector

final readonly class NullMetricsCollector implements MetricsCollectorInterface
{
    public function increment(string $name, array $labels = [], float $value = 1.0): void {}
    public function gauge(string $name, float $value, array $labels = []): void {}
    public function histogram(string $name, float $value, array $labels = []): void {}
}

Usage Example

// Middleware auto-collects RED metrics
$middleware = new MetricsMiddleware($collector);

// Manual metrics in use cases
$collector->increment('orders_created_total', ['channel' => 'web']);
$collector->gauge('active_connections', $pool->activeCount());
$collector->histogram('payment_duration_seconds', $elapsed, ['gateway' => 'stripe']);

// Expose via /metrics endpoint
$app->get('/metrics', new MetricsAction($collector));

RED Metrics Pattern

Rate     ──→ http_requests_total{method, path, status}
Errors   ──→ http_requests_total{status=~"5.."}
Duration ──→ http_request_duration_seconds{method, path}

Anti-patterns to Avoid

Anti-pattern	Problem	Solution
High cardinality labels	Prometheus storage explosion	Limit label values, no user IDs
No null implementation	Cannot disable metrics in tests	NullMetricsCollector
Inline metric names	Typos, inconsistency	Define constants or enum
Missing error metrics	Cannot calculate error rate	Track status codes
No histogram buckets	Default buckets don't fit use case	Configure per metric
Metrics in domain layer	Infrastructure leak	Keep in infrastructure only

References

For complete PHP templates and examples, see:

```
references/templates.md
```
— MetricsCollectorInterface, Counter, Gauge, Histogram, Prometheus, Middleware templates
```
references/examples.md
```
— Integration examples and tests