railway-metrics

What this skill does

# Railway Service Metrics

Query resource usage metrics for Railway services.

## When to Use

- User asks "how much memory is my service using?"
- User asks about CPU usage, network traffic, disk usage
- User wants to debug performance issues
- User asks "is my service healthy?" (combine with railway-service skill)

## Prerequisites

Get environmentId and serviceId from linked project:

```bash
railway status --json
```

Extract:
- `environment.id` → environmentId
- `service.id` → serviceId (optional - omit to get all services)

## MetricMeasurement Values

| Measurement | Description |
|-------------|-------------|
| CPU_USAGE | CPU usage (cores) |
| CPU_LIMIT | CPU limit (cores) |
| MEMORY_USAGE_GB | Memory usage in GB |
| MEMORY_LIMIT_GB | Memory limit in GB |
| NETWORK_RX_GB | Network received in GB |
| NETWORK_TX_GB | Network transmitted in GB |
| DISK_USAGE_GB | Disk usage in GB |
| EPHEMERAL_DISK_USAGE_GB | Ephemeral disk usage in GB |
| BACKUP_USAGE_GB | Backup usage in GB |

## MetricTag Values (for groupBy)

| Tag | Description |
|-----|-------------|
| DEPLOYMENT_ID | Group by deployment |
| DEPLOYMENT_INSTANCE_ID | Group by instance |
| REGION | Group by region |
| SERVICE_ID | Group by service |

## Query

```graphql
query metrics(
  $environmentId: String!
  $serviceId: String
  $startDate: DateTime!
  $endDate: DateTime
  $sampleRateSeconds: Int
  $averagingWindowSeconds: Int
  $groupBy: [MetricTag!]
  $measurements: [MetricMeasurement!]!
) {
  metrics(
    environmentId: $environmentId
    serviceId: $serviceId
    startDate: $startDate
    endDate: $endDate
    sampleRateSeconds: $sampleRateSeconds
    averagingWindowSeconds: $averagingWindowSeconds
    groupBy: $groupBy
    measurements: $measurements
  ) {
    measurement
    tags {
      deploymentInstanceId
      deploymentId
      serviceId
      region
    }
    values {
      ts
      value
    }
  }
}
```

## Example: Last Hour CPU and Memory

Use heredoc to avoid shell escaping issues:

```bash
bash <<'SCRIPT'
START_DATE=$(date -u -v-1H +"%Y-%m-%dT%H:%M:%SZ" 2>/dev/null || date -u -d "1 hour ago" +"%Y-%m-%dT%H:%M:%SZ")
ENV_ID="your-environment-id"
SERVICE_ID="your-service-id"

VARS=$(jq -n \
  --arg env "$ENV_ID" \
  --arg svc "$SERVICE_ID" \
  --arg start "$START_DATE" \
  '{environmentId: $env, serviceId: $svc, startDate: $start, measurements: ["CPU_USAGE", "MEMORY_USAGE_GB"]}')

${CLAUDE_PLUGIN_ROOT}/skills/lib/railway-api.sh \
  'query metrics($environmentId: String!, $serviceId: String, $startDate: DateTime!, $measurements: [MetricMeasurement!]!) {
    metrics(environmentId: $environmentId, serviceId: $serviceId, startDate: $startDate, measurements: $measurements) {
      measurement
      tags { deploymentId region serviceId }
      values { ts value }
    }
  }' \
  "$VARS"
SCRIPT
```

## Example: All Services in Environment

Omit serviceId and use groupBy to get metrics for all services:

```bash
bash <<'SCRIPT'
START_DATE=$(date -u -v-1H +"%Y-%m-%dT%H:%M:%SZ" 2>/dev/null || date -u -d "1 hour ago" +"%Y-%m-%dT%H:%M:%SZ")
ENV_ID="your-environment-id"

VARS=$(jq -n \
  --arg env "$ENV_ID" \
  --arg start "$START_DATE" \
  '{environmentId: $env, startDate: $start, measurements: ["CPU_USAGE", "MEMORY_USAGE_GB"], groupBy: ["SERVICE_ID"]}')

${CLAUDE_PLUGIN_ROOT}/skills/lib/railway-api.sh \
  'query metrics($environmentId: String!, $startDate: DateTime!, $measurements: [MetricMeasurement!]!, $groupBy: [MetricTag!]) {
    metrics(environmentId: $environmentId, startDate: $startDate, measurements: $measurements, groupBy: $groupBy) {
      measurement
      tags { serviceId region }
      values { ts value }
    }
  }' \
  "$VARS"
SCRIPT
```

## Time Parameters

| Parameter | Description |
|-----------|-------------|
| startDate | Required. ISO 8601 format (e.g., `2024-01-01T00:00:00Z`) |
| endDate | Optional. Defaults to now |
| sampleRateSeconds | Sample interval (e.g., 60 for 1-minute samples) |
| averagingWindowSeconds | Averaging window for smoothing |

**Tip:** For last hour, calculate startDate as `now - 1 hour` in ISO format.

## Output Interpretation

```json
{
  "data": {
    "metrics": [
      {
        "measurement": "CPU_USAGE",
        "tags": { "deploymentId": "...", "serviceId": "...", "region": "us-west1" },
        "values": [
          { "ts": "2024-01-01T00:00:00Z", "value": 0.25 },
          { "ts": "2024-01-01T00:01:00Z", "value": 0.30 }
        ]
      }
    ]
  }
}
```

- `ts` - timestamp in ISO format
- `value` - metric value (cores for CPU, GB for memory/disk/network)

## Composability

- **Get IDs**: Use railway-status skill or `railway status --json`
- **Check service health**: Use railway-service skill for deployment status
- **View logs**: Use railway-deployment skill if metrics show issues
- **Scale service**: Use railway-environment skill to adjust resources

## Error Handling

### Empty/Null Metrics

Services without active deployments return empty metrics arrays. When processing with jq, handle nulls:

```bash
# Safe iteration - skip nulls
jq -r '.data.metrics[]? | select(.values != null and (.values | length) > 0) | ...'

# Check if metrics exist before processing
jq -e '.data.metrics | length > 0' response.json && echo "has metrics"
```

### No Metrics Data

Service may be new or have no traffic. Check:
- Service has active deployment (stopped services have no metrics)
- Time range includes deployment period

### Invalid Service/Environment ID

Verify IDs with `railway status --json`.

### Permission Denied

User needs access to the project to query metrics.