Troubleshooting Common MPS HTMLGate IssuesMPS HTMLGate is a flexible tool used to bridge HTML content and backend systems, but like any complex software it can present problems that slow development or disrupt production. This guide walks you through common issues, diagnostic steps, and practical fixes so you can quickly restore functionality and improve long-term stability.
1. Symptoms and first checks
Before you change configurations or code, gather basic facts:
- Reproduce the issue consistently: Note exact steps, inputs, and timing.
- Check error messages and logs: Server logs, browser console, and any HTMLGate-specific logs often contain actionable clues.
- Confirm environment: Are you on dev, staging, or production? Has anything changed recently (deployments, config updates, library upgrades)?
- Rollback plan: Ensure you can revert to a previously working state if a fix worsens the problem.
2. Connectivity and network problems
Symptoms: timeouts, ⁄504 errors, inability to reach services.
Common causes and fixes:
- DNS issues: verify DNS resolution for backend endpoints (use dig/nslookup). If DNS was recently changed, allow TTL to propagate or update records.
- Firewall and routing: confirm firewalls, security groups, or load balancers aren’t blocking traffic. Test with curl or telnet to the target port.
- Proxy misconfiguration: if HTMLGate sits behind a reverse proxy, ensure proxy headers (Host, X-Forwarded-For, X-Forwarded-Proto) are correctly forwarded.
- Keepalive and connection limits: tune connection pool sizes and keepalive settings to avoid exhaustion under load.
- TLS/SSL handshake failures: check certificate validity, chain, and supported TLS versions. Use openssl s_client or an online TLS tester.
Quick commands to help debug:
- curl -v https://your-endpoint
- dig example.com +short
- openssl s_client -connect your-endpoint:443
3. Authentication and authorization failures
Symptoms: 401 Unauthorized, 403 Forbidden, or sporadic access denials.
Checks and resolutions:
- Token expiration: verify access tokens aren’t expired and refresh flow works.
- Clock skew: OAuth/JWT systems fail if client/server clocks differ; sync clocks with NTP.
- Key/secret rotation: ensure recent credential rotations are updated in HTMLGate config.
- Permission scopes/roles: confirm the authenticated principal has required scopes/roles for the requested resource.
- CORS: browser-based requests may be blocked by missing Access-Control-Allow-* headers; configure HTMLGate or upstream service to return correct CORS headers for allowed origins, methods, and headers.
4. Data mapping and transformation errors
Symptoms: malformed HTML, missing fields, serialization/parsing exceptions.
Troubleshooting steps:
- Validate input format: ensure incoming HTML or payload matches expected schema. Use validators or sample parsers.
- Encoding issues: check character encodings (UTF-8 vs others). Ensure requests and responses declare and use the same charset.
- Template bugs: if HTMLGate uses templates to generate or transform content, inspect template logic for incorrect variable names or control flow.
- JSON/XML mismatches: if converting between formats, verify field names, nesting, and types; add robust parsing with helpful error messages.
- Logging payload samples: log (sanitized) samples of inputs and outputs to compare expected vs actual.
5. Performance and scaling problems
Symptoms: slow responses, increased latency under load, timeouts.
Potential causes and mitigations:
- Blocking operations: identify long-running synchronous tasks; convert to async or move to background jobs.
- Resource limits: CPU, memory, file descriptors—monitor and scale horizontally/vertically as needed.
- Database bottlenecks: slow queries or lack of indexes—profile queries and add appropriate indexes or caching.
- Caching: add or tune caches (HTTP, CDN, in-memory) for frequently requested content.
- Connection pooling: tune pool sizes to match concurrency patterns; avoid creating/destroying connections per request.
- Rate limiting and throttling: ensure clients aren’t throttled unintentionally; add graceful backoff and retry logic.
Tools to profile performance:
- Application profiling (e.g., flame graphs)
- APM solutions (New Relic, Datadog, Jaeger)
- Load testing (wrk, k6)
6. Browser rendering and client-side issues
Symptoms: pages look incorrect, scripts/styles not loading, layout shifts.
Check client-side causes:
- Resource paths: ensure static assets are referenced with correct base paths. Misconfigured base URLs cause 404s for CSS/JS.
- CSP (Content Security Policy): strict CSP can block inline scripts or external resources. Tune CSP headers to allow required sources.
- Missing polyfills: older browsers may require polyfills for JS features—serve appropriate bundles or transpile.
- Mixed content: secure pages (HTTPS) blocked from loading insecure (HTTP) scripts—use HTTPS for all resources.
- Cache invalidation: stale assets in CDN or browser cache—bump asset fingerprint/hashes on deploy.
Use browser devtools to inspect network requests, console errors, and layout issues.
7. Version compatibility and dependency issues
Symptoms: new errors after upgrades, build failures, API mismatches.
How to handle:
- Check changelogs and release notes for HTMLGate and downstream libraries before upgrading.
- Lock dependency versions with a lockfile and perform upgrades in a controlled environment.
- Run integration tests against staging environments that mimic production.
- Use semantic versioning awareness—major version changes often include breaking API changes.
8. Logging, observability, and actionable alerts
Good practices:
- Centralize logs (ELK, Loki, Splunk) and ensure logs include correlation IDs to trace requests end-to-end.
- Emit structured logs (JSON) with log levels and contextual fields.
- Instrument metrics (request latency, error rate, throughput) and set sensible alert thresholds.
- Use distributed tracing to follow request flow across services and identify bottlenecks.
Example useful metrics:
- 95th/99th percentile response latency
- Error rate by endpoint
- Active connections and queue lengths
9. Common configuration pitfalls
Frequent misconfigurations:
- Hardcoded endpoints or credentials in code instead of environment/config management.
- Insufficient timeouts (too short leading to spurious failures, or too long causing resource hangs).
- Default development settings used in production (debug logging, sample keys).
- Permissive CORS or overly broad CSP during debugging left enabled.
Checklist for production readiness:
- Secrets managed in a vault or secret store.
- Timeouts and retries configured with exponential backoff.
- Proper log rotation and retention policies.
- Health checks and readiness probes for orchestration systems.
10. When to escalate and seek help
Escalate if:
- The issue impacts business-critical flows beyond your change window and you can’t identify a fix.
- You suspect a security breach (unexpected access patterns, credential use, or data exposure).
- Reproducing the issue requires deep internal knowledge of third-party services or platform internals.
Information to include when filing a ticket:
- Clear reproduction steps
- Exact error messages and relevant log excerpts
- Request/response samples (sanitized)
- Environment details (versions, configs, recent changes)
- Timeline of occurrence and impact
Example troubleshooting checklist (short)
- Reproduce and gather logs.
- Confirm environment and recent changes.
- Test connectivity and TLS.
- Verify auth tokens/permissions and clock sync.
- Inspect transformations and encoding.
- Profile for performance bottlenecks.
- Check browser devtools for client issues.
- Review dependencies and config files.
- Centralize logs and enable tracing.
- Escalate with a detailed incident ticket.
Troubleshooting MPS HTMLGate effectively is mostly about methodical diagnosis, good observability, and cautious changes. Follow the steps above to narrow root causes quickly and apply targeted fixes that reduce recurrence.
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