Makefile: Fix performance issues caused by tracing in binaries

We have observed multiple times already that short-lived Go binaries
spawned by Gitaly have major initialization overhead because they need
to initialize the `awk-sdk-go` dependency. This dependency has megabytes
of maps containing all the different datacenters of AWS, and this cost
quickly adds up in case the binary only does very limited work. As a
result, we have seen runtime of `gitaly-hooks` and `gitaly-lfs-smudge`
to be dominated by this initialization.

The thing though is that neither of these has a direct dependency on
`awk-sdk-go`. Instead, it is being pulled in as an indirect dependency
via `labkit`, but only if compiled with tracing enabled. And we do in
fact compile all binaries with tracing enabled by default.

Ultimately, having tracing in such short-lived binaries isn't all that
helpful, and in combination with the performance issues we're observing
it is time to drop the tracing infrastructure there. We cannot drop the
dependency on `labkit` though: it's required so that we can inject and
extract the correlation ID via the environment. But luckily, tracing is
only enabled when specific build tags are set. Conversely, if they're
unset, we also don't pull in the problematic `awk-sdk-go` package.

Fix the performance issue by splitting up Go build tags to be per
binary. Like this, we can keep tracing enabled in both Praefect and
Gitaly while we disable it for all the other binaries. Furthermore, this
also allows us to inject the Git2go-specific build tags only for the
`gitaly-git2go-v14` binary.

Changelog: fixed

1 files changed, 8 insertions, 5 deletions

diff --git a/Makefile b/Makefile
index 357c7b426..95df09742 100644
--- a/Makefile
+++ b/Makefile
@@ -65,7 +65,8 @@ GITALY_PACKAGE    := gitlab.com/gitlab-org/gitaly/v14
 BUILD_TIME        := $(shell date +"%Y%m%d.%H%M%S")
 GITALY_VERSION    := $(shell ${GIT} describe --match v* 2>/dev/null | sed 's/^v//' || cat ${SOURCE_DIR}/VERSION 2>/dev/null || echo unknown)
 GO_LDFLAGS        := -X ${GITALY_PACKAGE}/internal/version.version=${GITALY_VERSION} -X ${GITALY_PACKAGE}/internal/version.buildtime=${BUILD_TIME} -X ${GITALY_PACKAGE}/internal/version.moduleVersion=${MODULE_VERSION}
-GO_BUILD_TAGS     := tracer_static,tracer_static_jaeger,tracer_static_stackdriver,continuous_profiler_stackdriver,static,system_libgit2
+SERVER_BUILD_TAGS := tracer_static,tracer_static_jaeger,tracer_static_stackdriver,continuous_profiler_stackdriver
+GIT2GO_BUILD_TAGS := static,system_libgit2
 
 # Dependency versions
 GOLANGCI_LINT_VERSION     ?= 1.44.2
@@ -216,12 +217,11 @@ find_go_sources       = $(shell find ${SOURCE_DIR} -type d \( -name ruby -o -nam
 # run_go_tests will execute Go tests with all required parameters. Its
 # behaviour can be modified via the following variables:
 #
-# GO_BUILD_TAGS: tags used to build the executables
 # TEST_OPTIONS: any additional options
 # TEST_PACKAGES: packages which shall be tested
 run_go_tests = PATH='${SOURCE_DIR}/internal/testhelper/testdata/home/bin:${PATH}' \
     TEST_TMP_DIR='${TEST_TMP_DIR}' \
-    ${GOTESTSUM} --format ${TEST_FORMAT} --junitfile ${TEST_REPORT} -- -ldflags '${GO_LDFLAGS}' -tags '${GO_BUILD_TAGS}' ${TEST_OPTIONS} ${TEST_PACKAGES}
+    ${GOTESTSUM} --format ${TEST_FORMAT} --junitfile ${TEST_REPORT} -- -ldflags '${GO_LDFLAGS}' -tags '${SERVER_BUILD_TAGS},${GIT2GO_BUILD_TAGS}' ${TEST_OPTIONS} ${TEST_PACKAGES}
 
 unexport GOROOT
 export GOBIN                      = ${BUILD_DIR}/bin
@@ -268,6 +268,9 @@ help:
 ## Build Go binaries and install required Ruby Gems.
 build: ${SOURCE_DIR}/.ruby-bundle ${GITALY_EXECUTABLES}
 
+gitaly:            GO_BUILD_TAGS = ${SERVER_BUILD_TAGS}
+praefect:          GO_BUILD_TAGS = ${SERVER_BUILD_TAGS}
+gitaly-git2go-v14: GO_BUILD_TAGS = ${GIT2GO_BUILD_TAGS}
 gitaly-git2go-v14: libgit2
 
 .PHONY: ${GITALY_EXECUTABLES}
@@ -380,7 +383,7 @@ check-mod-tidy:
 .PHONY: lint
 ## Run Go linter.
 lint: ${GOLANGCI_LINT} libgit2
-	${Q}${GOLANGCI_LINT} run --build-tags "${GO_BUILD_TAGS}" --out-format tab --config ${GOLANGCI_LINT_CONFIG} ${GOLANGCI_LINT_OPTIONS}
+	${Q}${GOLANGCI_LINT} run --build-tags "${SERVER_BUILD_TAGS},${GIT2GO_BUILD_TAGS}" --out-format tab --config ${GOLANGCI_LINT_CONFIG} ${GOLANGCI_LINT_OPTIONS}
 
 .PHONY: format
 ## Run Go formatter and adjust imports.
@@ -487,7 +490,7 @@ ${SOURCE_DIR}/NOTICE: ${BUILD_DIR}/NOTICE
 
 ${BUILD_DIR}/NOTICE: ${GO_LICENSES} clean-ruby-vendor-go
 	${Q}rm -rf ${BUILD_DIR}/licenses
-	${Q}GOOS=linux GOFLAGS="-tags=${GO_BUILD_TAGS}" ${GO_LICENSES} save ${SOURCE_DIR}/... --save_path=${BUILD_DIR}/licenses
+	${Q}GOOS=linux GOFLAGS="-tags=${SERVER_BUILD_TAGS},${GIT2GO_BUILD_TAGS}" ${GO_LICENSES} save ${SOURCE_DIR}/... --save_path=${BUILD_DIR}/licenses
 	${Q}go run ${SOURCE_DIR}/_support/noticegen/noticegen.go -source ${BUILD_DIR}/licenses -template ${SOURCE_DIR}/_support/noticegen/notice.template > ${BUILD_DIR}/NOTICE
 
 ${BUILD_DIR}: