Log timestamps stuck in UTC; TZ env has no effect (no tzdata in image)

[guisea]

Summary

Log timestamps are always UTC and can't be changed. Setting TZ on the container has no effect.

[vaultwarden-api] INFO: 2026/09/09 00:14:55 api_client.go:221: Authentication successful

Cause

pkg/logger/logger.go uses log.Ldate|log.Ltime|log.Lshortfile (no log.LUTC), so Go formats timestamps in time.Local — this part is fine.

But the runtime image (Dockerfile, FROM alpine:3.24) installs only ca-certificates wget. With no tzdata and no TZ, Go's time.Local resolves to UTC, and -e TZ=... can't work because there's no /usr/share/zoneinfo to load.

Fix

Embed the zoneinfo DB in the binary so TZ works with no image change and no extra layer (matters for the read_only: true compose setup):

// main package
import _ "time/tzdata"

Then TZ selects the zone:

environment:
  - TZ=Pacific/Auckland

Adds ~450 KB to the binary. Alternative: RUN apk add --no-cache tzdata in the runtime stage.

Worth a line in the README documenting TZ once either is in.