Bazel commands

Notes about using bazel

Flaky tests

bazel test --runs_per_test=100 --cache_test_results=no --test_arg=-test.v --test_output=streamed <target_path> --test_filter=Testxxxxx

To run with race detetor

bazel test ... --test_filter=TestRunForever --runs_per_test=100 --@io_bazel_rules_go//go/config:race

Run benchmark

bazel run //target:go_default_test \
  --test_sharding_strategy=disabled -- -test.bench=Benchmark

Run with environment variables

• I used this for company-s debugging an grpc GOAWAY error.

bazel test --test_arg=-test.v --test_output=streamed  <your-package>/... --test_filter=TestRPC --test_env=GODEBUG=http2debug=2

Test Coverage

bazel coverage --nocache_test_results <your-package-path>:all
 
go install github.com/wadey/gocovmerge@latest
 
// The path of the coverage.dat is from Bazel command output.
$GOPATH/bin/gocovmerge <path>/<to>/<your>/<coverage-dat>/coverage.dat > bazel-cover.out
 
go tool cover -func bazel-cover.out

Cross platform compilation for go

for x86 linux

This is needed in company-s because all Macs are ARM.

bazel build --platforms=@io_bazel_rules_go//go/toolchain:linux_amd64 //your-targets/...

The built will be at bazel-bin/your/target/locaiton (i.e. bazel-bin/ dir)

Also, when not using bazel, but just go toolchain directly, add env variables as below:

GOOS=linux GOARCH=amd64 go build <package>

Command line Auto completion 

For bash + mac, in ~/.bash\_profile

source $(dirname $(readlink -f `which bazel`))/bazel-complete.bash

WARNING

This could be quite slow on big projects!

Reference:

• https://bazel.build/install/completion#bash 
• The key is the ‘bazel-complete.bash’ file.

Query dependencies

What are the packages that depend on qtdb lib?

bazel query 'rdeps(..., //vistar/geo/qtdb:go_default_library)' --output package 

which packages does qtdb depend on?

bazel query 'deps(//vistar/geo/qtdb:go_default_library)' --output package