## Participants * @M_Alvarez ## Summary This epic tracks the migration of GitLab's core Go-based systems to use Go's standard `slog` package for structured logging. This migration is a prerequisite for consolidating our logging setup into Labkit and ensuring consistency across our observability stack. ## Goals - Migrate core GitLab Go systems to use `slog` for structured logging - Establish migration patterns and best practices that other teams can follow - De-risk the consolidation of logging setup into Labkit by making incremental changes - Ensure backward compatibility during the migration period - Validate that `slog` meets our performance and functionality requirements in production ## Execution Flow This epic will have to be tackled in roughly this order: 1. **GitLab Shell** - this will give us some degree of confidence in the new package and enable us to identify a more comprehensive list of requirements for our v2 logging package. 2. **HTTP Access Logger Design -** we'll need to provide a way for the v2 Log package to either work with the existing http access logger, or build a new slog-based one that we can use for subsqeuent migrations. 3. **GitLab Workhorse** - this might be one of the simpler of the remaining services to migrate - with 31 identified package imports across the system. 4. **GitLab Pages** - Static site hosting service 5. **GitLab Container Registry** - Container image registry 6. **Other Go services** - Additional Go-based services as identified ## Migration Strategy ### Phase 1: Proof of Concept - Select a low-risk service or component for initial migration - Validate `slog` performance and functionality - Document migration patterns and gotchas - Create reusable migration utilities/helpers ### Phase 2: Core Services Migration - Migrate high-priority services one at a time - Monitor for performance regressions or issues - Gather feedback from service owners - Refine migration patterns based on learnings ### Phase 3: Remaining Services - Complete migration of remaining Go services - Deprecate old logging implementations - Update documentation and guidelines ## Success Criteria - [x] Foundation is laid for Labkit log package integration - [ ] All core Go services are using the LabKit v2 Log package for structured logging - [ ] No performance regressions observed in production - [ ] Migration patterns documented and shared - [ ] Linters have been updated for all services to ensure we do not introduce any other logging packages ## Risks and Mitigations **Risk**: Performance impact on high-traffic services - **Mitigation**: Thorough benchmarking and gradual rollout with monitoring **Risk**: Breaking changes to existing log consumers - **Mitigation**: Maintain log format compatibility where possible, communicate changes clearly **Risk**: Custom logging requirements not met by `slog` - **Mitigation**: Leverage `slog`'s handler interface for customization ## Related Work - Parent Epic: #235 - Defining Logging Standards for Developers - Related Epic: Implement Labkit Log Package using slog (to be created) - Design Doc: [Observability Field Standardisation](https://handbook.gitlab.com/handbook/engineering/architecture/design-documents/observability_field_standardisation/) ### Status <!-- STATUS NOTE START --> ## Status 2026-07-09 :clock1: **total hours spent this week by all contributors**: 8 :tada: **achievements**: * Opened third MR, migrating the bulk of Workhorse global logging call sites to the new V2 package / slog. * [Initial steps made toward defining slog usage standards](https://gitlab.com/gitlab-org/labkit/-/work_items/125); supporting guidance for developers adoption the new package :issue-blocked:: **blockers**: * None :arrow_forward: **next**: * Land a couple large Workhorse MRs migrating initially excluded logging sites (Context field logging, logs using in-project bespoke logging package, access logging) * Document slog usage best practices _Copied from https://gitlab.com/groups/gitlab-org/quality/-/epics/266#note_3539097743_ <!-- STATUS NOTE END --> ## Want to chat? Join us in [#devex-log-field-migration-efforts](https://gitlab.enterprise.slack.com/archives/C09JQ7L1QDS) on Slack