varnishlog
Display Varnish HTTP request logs
TLDR
SYNOPSIS
varnishlog [-c] [-b] [-q query] [-i tag] [options]
DESCRIPTION
varnishlog reads the Varnish Shared Memory Log (VSL) and displays detailed request and response information in real time. It shows the full lifecycle of HTTP transactions including client requests, backend fetches, cache decisions, and response headers.The tool provides powerful filtering through the VSL query language, allowing you to isolate specific transactions by status code, URL pattern, or any logged field. Client-side (-c) and backend-side (-b) views can be shown independently, and grouping modes organize output by request, session, or raw log entries. This makes it the primary debugging tool for understanding Varnish cache behavior.
PARAMETERS
-c
Show client-side transactions only.-b
Show backend-side transactions only.-q QUERY
VSL query expression to filter transactions.-i TAGLIST
Include only records with specified tags (comma-separated).-I TAGREGEX
Include only records matching tag and regex pattern.-x TAGLIST
Exclude records with specified tags.-X TAGREGEX
Exclude records matching tag and regex pattern.-g MODE
Grouping mode (raw, vxid, request, session).-d
Process old log entries first.-w FILENAME
Write output to file.
CAVEATS
Requires a running Varnish instance. Familiarity with VSL query language is helpful for effective filtering. Output can be very verbose without filters.
HISTORY
varnishlog is part of Varnish Cache, displaying the Varnish Shared Memory Log for debugging.
SEE ALSO
varnishhist(1), varnishstat(1), varnishd(1)
