====== Runbook: Health Check ======

<WRAP round info>
**Duration:** ~2 minutes \\
**Role:** Gateway Operator \\
**Frequency:** Daily / Automated
</WRAP>

Check Gateway availability and functionality.

----

===== Workflow =====

<mermaid>
flowchart TD
    A[Start Health Check] --> B[/health Endpoint]
    B --> C{Healthy?}
    C -->|Yes| D[API Test]
    C -->|No| E[Check logs]
    D --> F{Data returned?}
    F -->|Yes| G[OK - Done]
    F -->|No| H[Check DSN]
    E --> I[Restart server]
    H --> I

    style G fill:#e8f5e9
    style E fill:#ffebee
    style H fill:#fff3e0
</mermaid>

----

===== 1. Basic Health Check =====

<code bash>
# Simple Health Check
curl -s -o /dev/null -w "%{http_code}" http://localhost:5000/health

# Expected response: 200
</code>

<code bash>
# With response body
curl -s http://localhost:5000/health

# Expected response: "Healthy"
</code>

----

===== 2. Extended Health Check =====

<code bash>
# Swagger reachable?
curl -s -o /dev/null -w "%{http_code}" http://localhost:5000/swagger

# Check API version
curl -s http://localhost:5000/api/v1/info | jq
</code>

----

===== 3. DSN Connectivity =====

<code bash>
# Test all DSN
for dsn in demo production reporting; do
  echo "Testing $dsn..."
  curl -s -o /dev/null -w "$dsn: %{http_code}\n" \
    "http://localhost:5000/api/v1/dsn/$dsn/tables"
done
</code>

**PowerShell version:**

<code powershell>
$dsns = @("demo", "production", "reporting")
foreach ($dsn in $dsns) {
    $result = Invoke-WebRequest -Uri "http://localhost:5000/api/v1/dsn/$dsn/tables" -UseBasicParsing
    Write-Host "$dsn : $($result.StatusCode)"
}
</code>

----

===== 4. Measure Response Time =====

<code bash>
# Single query
curl -s -o /dev/null -w "Time: %{time_total}s\n" \
  "http://localhost:5000/api/v1/dsn/demo/tables/Products?\$top=10"

# Multiple runs
for i in {1..5}; do
  curl -s -o /dev/null -w "%{time_total}\n" \
    "http://localhost:5000/api/v1/dsn/demo/tables/Products?\$top=10"
done | awk '{sum+=$1} END {print "Average: " sum/NR "s"}'
</code>

----

===== 5. Checklist =====

| # | Check | Expected | Done |
|---|-------|----------|------|
| 1 | /health | 200 + "Healthy" | [ ] |
| 2 | /swagger | 200 | [ ] |
| 3 | DSN "demo" reachable | 200 | [ ] |
| 4 | Response time | < 1s | [ ] |
| 5 | No errors in logs | No ERROR | [ ] |

----

===== Automated Health Check =====

**Cron (Linux):**

<code bash>
# /etc/cron.d/gateway-health
*/5 * * * * root curl -sf http://localhost:5000/health || systemctl restart data-gateway
</code>

**Scheduled Task (Windows):**

<code powershell>
# health-check.ps1
$response = Invoke-WebRequest -Uri "http://localhost:5000/health" -UseBasicParsing -TimeoutSec 5
if ($response.StatusCode -ne 200) {
    Restart-Service -Name "DataGateway" -Force
    Send-MailMessage -To "admin@example.com" -Subject "Gateway Restart" -Body "Gateway was automatically restarted"
}
</code>

----

===== Troubleshooting =====

| Problem | Cause | Solution |
|---------|-------|----------|
| ''Connection refused'' | Gateway not started | Start server |
| ''503 Service Unavailable'' | Startup not finished | Wait 30s, retry |
| ''500 Internal Server Error'' | Config error | Check logs |
| Timeout | Gateway overloaded | Reduce load, increase resources |

----

===== Thresholds =====

| Metric | Green | Yellow | Red |
|--------|-------|--------|-----|
| Response time | < 500ms | 500ms-2s | > 2s |
| Error rate | < 1% | 1-5% | > 5% |
| CPU | < 50% | 50-80% | > 80% |
| Memory | < 70% | 70-90% | > 90% |

----

===== Related Runbooks =====

  * [[.:server-starten|Start Server]] - On failure
  * [[.:logs-pruefen|Check Logs]] - Error analysis
  * [[..:monitoring:prometheus|Prometheus]] - Automatic monitoring

----

<< [[.:dsn-verwalten|<- Manage DSN]] | [[.:logs-pruefen|-> Check Logs]] >>

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//Wolfgang van der Stille @ EMSR DATA d.o.o. - Data Gateway Professional//

{{tag>operator runbook health check monitoring}}