enable go module support in pipeline

- enable Go module support
- add compile flags to ditch C compiler
- enable caching per git branch

Signed-off-by: Daniel Andrei Minca <mandrei17@gmail.com>

.gitlab-ci.yml

@@ -1,17 +1,25 @@
 image: golang:alpine
 
+variables:
+  GO111MOD: "on"
+  CGO_ENABLED: "0"
+  GOOS: "linux"
+
+cache:
+  key: ${CI_COMMIT_REF_SLUG}
+  paths:
+    - /var/cache/apk
+    - /go/pkg/mod
+
 stages:
   - test
   - review
 
 before_script:
-  - apk add --no-cache git build-base bash make
-  - mkdir -p /go/src/gitlab.com/$CI_PROJECT_NAMESPACE /go/src/_/builds
-  - cp -r $CI_PROJECT_DIR /go/src/gitlab.com/$CI_PROJECT_PATH
-  - ln -s /go/src/gitlab.com/$CI_PROJECT_NAMESPACE /go/src/_/builds/$CI_PROJECT_NAMESPACE
+  - apk add --no-cache git make
   - go get github.com/golangci/golangci-lint/cmd/golangci-lint
   - go install github.com/golangci/golangci-lint/cmd/golangci-lint
-  - make dep
+  - make tidy
 
 unit_tests:
   stage: test

Makefile

@@ -6,9 +6,9 @@ PACKAGE_PATH := "$(GOPATH)/src/$(PACKAGE_NAME)"
 PACKAGE_LIST := $(shell go list $(PACKAGE_NAME)/... | grep -v /vendor/)
 GO_FILES := $(shell find . -name '*.go' | grep -v /vendor/ | grep -v _test.go)
 
-.PHONY: all lint test rase coverage dep
+.PHONY: all lint test rase coverage tidy
 
-all: dep test race lint
+all: tidy test race lint
 
 lint: ## Lint the files
 	@golangci-lint run ./...
@@ -16,14 +16,14 @@ lint: ## Lint the files
 test: ## Run unittests
 	@go test -short $(PACKAGE_NAME)/...
 
-race: dep ## Run data race detector
+race: tidy ## Run data race detector
 	@go test -race -short ${PACKAGE_LIST}
 
 coverage: ## Generate global code coverage report
 	@go test -cover -v -coverpkg=$(PACKAGE_NAME)/... ${PACKAGE_LIST}
 
-dep: ## Get the dependencies
-	@go get -v -d -t $(PACKAGE_NAME)/...
+tidy: ## Get the dependencies
+	@go mod tidy
 
 help: ## Display this help screen
 	@grep -h -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'