fix(build): use netgo DNS resolver for release binaries - #4965
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dennismdejong wants to merge 1 commit into
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fix(build): use netgo DNS resolver for release binaries#4965dennismdejong wants to merge 1 commit into
dennismdejong wants to merge 1 commit into
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Distroless base images do not ship the dynamic libraries required by libc's getaddrinfo (used by the CGO DNS resolver). As a result, distroless-based Dex builds fail to resolve *.local hostnames, e.g. LDAP connectors addressing services via .svc.cluster.local. Build the release binaries with the netgo build tag so that the pure Go DNS resolver is used instead, which has no such dependency. CGO remains enabled for SQLite storage support. Closes dexidp#2469 Signed-off-by: dennismdejong <dennis@caberdo.nl>
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Overview
Build the Dex release binaries with the
netgobuild tag so the pure Go DNS resolver is used instead of libc-basedgetaddrinfo.What this PR does / why we need it
Distroless base images do not ship the dynamic libraries required by libc's
getaddrinfo(which callsdlopen). When CGO is enabled, the Go standard library uses the CGO resolver for*.localhostnames, so distroless-based Dex builds fail with:Building the release binaries with
-tags netgoforces the pure Go DNS resolver, which has no dependency on dynamic libraries and works on distroless images. CGO remains enabled for SQLite storage support.Closes #2469
Special notes for your reviewer
CGO_ENABLED=1 go build -tags netgo ./...compiles for the main module,examples/andapi/v2.GODEBUG=netdns=2that the resulting binary reports it was "compiled without support for the cgo resolver".sqlite3_open) are still present in the binary.