Guance Learn

Observability questions

Focused answers for definitions, architecture choices, troubleshooting, pricing, and evaluation.

Find the index of an item in a Python list illustration
Explainer

Find the index of an item in a Python list

Find the first or every matching list index, handle missing values, and search by a condition with enumerate and next.

  • Engineering
  • Explainer
2 min read
Illustration of log collection and monitoring
Explainer

Fix Fluentd’s “pattern not match” warning

Find the log line that fails Fluentd parsing, check timestamps and multiline boundaries, and preserve unmatched input while correcting the parser.

  • Engineering
  • Explainer
2 min read
Illustration of application infrastructure and operations
Technical guide

How to fix HTTP 413: request body too large

Locate the layer rejecting an oversized request and coordinate Express, multipart, Nginx, and upstream limits without removing resource safeguards.

  • Engineering
  • Technical guide
4 min read
Illustration of log collection and monitoring
Explainer

Parse JSON logs into Elasticsearch fields with Fluent Bit

Parse JSON records, optionally lift nested fields, and avoid field collisions and Elasticsearch mapping errors in Fluent Bit.

  • Engineering
  • Explainer
2 min read
Illustration of log collection and monitoring
Explainer

Fix Fluentd’s “unreadable, it is excluded” warning

Check Fluentd’s service identity, file and directory permissions, rotation settings, and path selection when a tailed file is unreadable.

  • Engineering
  • Explainer
2 min read
Illustration of log collection and monitoring
Explainer

Send one Fluentd source through multiple filters and outputs

Chain Fluentd filters in order, fan out events with copy, and account for shared records, buffers, and output failures.

  • Engineering
  • Explainer
2 min read
Illustration of log collection and monitoring
Explainer

Rotate Fluentd file output by time slice

Configure hourly Fluentd output files, understand append and timekey_wait, and separate compression, buffering, and retention.

  • Engineering
  • Explainer
2 min read
Illustration of log collection and monitoring
Explainer

Fluentd vs. Kafka: where each belongs in a logging pipeline

Understand Fluentd collection and routing, Kafka retention and replay, and when a broker is worth the operational complexity.

  • Engineering
  • Explainer
3 min read
Generate random integers between two bounds in Python illustration
Explainer

Generate random integers between two bounds in Python

Use randint for inclusive integer bounds, randrange for an exclusive stop, and secrets for security-sensitive randomness.

  • Engineering
  • Explainer
2 min read
Data organization and search illustration
Technical guide

Count the fields in an Elasticsearch index

Inspect mappings and count nested fields, multi-fields, aliases, and runtime fields without confusing top-level properties with the mapping limit.

  • Engineering
  • Technical guide
2 min read
Illustration of metrics, monitoring, and technical investigation
Technical guide

Count requests over a time period with Prometheus

Use increase() and label aggregation to estimate request totals, including a Grafana interval total and reset caveats.

  • Engineering
  • Technical guide
3 min read
Secure network connections and certificate management
Technical guide

Make Chrome trust a localhost development certificate

Use mkcert or a carefully configured local certificate with matching SAN entries, then verify Chrome trust without bypassing certificate checks.

  • Engineering
  • Technical guide
3 min read