Applogs

Applogs, short for application logs, are records generated by software applications to document events, errors, transactions, and operational state. They are used for debugging, troubleshooting, performance monitoring, auditing, and compliance.

Typical content includes a timestamp, log level, message, logger or component name, and contextual data such as request identifiers, user IDs, host name, environment, and thread or process information. Logs may be plain text or structured data in JSON or key-value formats.

Log generation can occur at various layers and can be written to local files, databases, or centralized logging systems. Centralized solutions aggregate logs from multiple services, environments, and devices, enabling search, correlation, and alerting. Common transport and storage approaches include log shippers (for example, Filebeat or Fluentd), syslog, HTTP intake, and storage in systems like Elasticsearch, Splunk, Graylog, or cloud log services.

Best practices include structured logging, using consistent log levels, adding correlation and trace IDs to enable distributed tracing, log rotation and retention policies, data redaction for privacy, and security controls to protect log integrity.

Applications include troubleshooting, incident response, performance analysis, security auditing, and compliance reporting. Logs can be used to reproduce issues, measure latency, and detect anomalies.

Common tooling comprises the Elastic Stack, Splunk, Graylog, Loki, and cloud-native logging services; OpenTelemetry is used for collecting and exporting log data among other telemetry.