Use k6's linter config

.gitignore

@@ -13,3 +13,9 @@
 
 # Dependency directories (remove the comment below to include it)
 # vendor/
+
+./k6
+
+# we use the config from the main k6's repository
+# https://github.com/grafana/k6/blob/master/.golangci.yml
+.golangci.yml

Makefile

@@ -0,0 +1,46 @@
+MAKEFLAGS += --silent
+GOLANGCI_CONFIG ?= .golangci.yml
+
+all: clean lint test build
+
+## help: Prints a list of available build targets.
+help:
+	echo "Usage: make <OPTIONS> ... <TARGETS>"
+	echo ""
+	echo "Available targets are:"
+	echo ''
+	sed -n 's/^##//p' ${PWD}/Makefile | column -t -s ':' | sed -e 's/^/ /'
+	echo
+	echo "Targets run by default are: `sed -n 's/^all: //p' ./Makefile | sed -e 's/ /, /g' | sed -e 's/\(.*\), /\1, and /'`"
+
+## build: Builds a custom 'k6' with the local extension. 
+build:
+	xk6 build --with $(shell go list -m)=.
+
+## linter-config: Checks if the linter config exists, if not, downloads it from the main k6 repository.
+linter-config:
+	test -s "${GOLANGCI_CONFIG}" || (echo "No linter config, downloading from main k6 repository..." && curl --silent --show-error --fail --no-location https://raw.githubusercontent.com/grafana/k6/master/.golangci.yml --output "${GOLANGCI_CONFIG}")
+
+## check-linter-version: Checks if the linter version is the same as the one specified in the linter config.
+check-linter-version:
+	(golangci-lint version | grep "version $(shell head -n 1 .golangci.yml | tr -d '\# ')") || echo "Your installation of golangci-lint is different from the one that is specified in k6's linter config (there it's $(shell head -n 1 .golangci.yml | tr -d '\# ')). Results could be different in the CI."
+
+## test: Executes any tests.
+test:
+	go test -race -timeout 30s ./...
+
+## lint: Runs the linters.
+lint: linter-config check-linter-version
+	echo "Running linters..."
+	golangci-lint run --out-format=tab ./...
+
+## check: Runs the linters and tests.
+check: lint test
+
+## clean: Removes any previously created artifacts/downloads.
+clean:
+	echo "Cleaning up..."
+	rm -f ./k6
+	rm .golangci.yml	
+
+.PHONY: test lint check build clean linter-config check-linter-version