improve Go setup

.github/workflows/lint.yml

@@ -0,0 +1,31 @@
+name: Lint
+
+permissions: {}
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  lint:
+    permissions:
+      contents: read
+    name: Run on Ubuntu
+    runs-on: ubuntu-latest
+    steps:
+      - name: Clone the code
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+
+      - name: Setup Go
+        uses: actions/setup-go@4a3601121dd01d1626a1e23e37211e3254c1c06c # v6.4.0
+        with:
+          go-version-file: go.mod
+
+      - name: Check linter configuration
+        run: make lint-config
+      - name: Run linter
+        run: make lint

.gitignore

@@ -1,2 +1,3 @@
 .idea/
 /vendor/
+bin/

.golangci.yml

@@ -0,0 +1,97 @@
+version: "2"
+run:
+  allow-parallel-runners: true
+  build-tags:
+    - integration
+linters:
+  default: none
+  enable:
+    - asasalint # warns about passing []any to func(...any) without expanding it
+    - asciicheck # non ascii symbols
+    - copyloopvar # copying loop variables
+    - errcheck  # unchecked errors
+    - exhaustive # exhaustiveness of enum switch statements
+    - ginkgolinter # ginkgo and gomega - only if ginkgo/gomega is used
+    - gocritic # bugs, performance, style
+    - gocyclo # cyclomatic complexity of functions
+    - godoclint # go documentation linting against best practices
+    - gosec # potential security problems
+    - govet # basically 'go vet'
+    - importas # enforces consistent import aliases.
+    - ineffassign # ineffectual assignments
+    - loggercheck # check for even key/value pairs in logger calls
+    - modernize # suggest simplifications to Go code, using modern language and library features
+    - misspell # spelling checks
+    - nakedret  # naked returns (named return parameters and an empty return)
+    - noctx  # http requests without context.Context
+    - nolintlint  # badly formatted nolint directives
+    - predeclared # shadowing predeclared identifiers
+    - promlinter # only if prom is used for creating metrics
+    - revive # better version of golint
+    - spancheck # only if OpenTelemetry is used
+    - staticcheck # many static checks
+    - thelper # test helpers not starting with t.Helper()
+    - unconvert # unnecessary type conversions
+    - unparam # unused function parameters
+    - unused # unused constants, variables,functions, types
+    - usestdlibvars # using variables/constants from the standard library
+    - usetesting # reports uses of functions with replacement inside the testing package
+    - whitespace # unnecessary newlines
+  settings:
+    loggercheck:
+      kitlog: false
+      slog: false
+      zap: false
+      require-string-key: true
+      no-printf-like: true
+    modernize:
+      disable:
+        - omitzero
+    gocritic:
+      disabled-checks:
+        - ifElseChain # disabled ifElseChain because this is purely stylistic
+    revive:
+      rules:
+        # The following rules are recommended https://github.com/mgechev/revive#recommended-configuration
+        - name: blank-imports
+        - name: context-as-argument
+        - name: context-keys-type
+        - name: error-return
+        - name: error-strings
+        - name: error-naming
+        - name: if-return
+        - name: increment-decrement
+        - name: var-naming
+        - name: var-declaration
+        - name: range
+        - name: receiver-naming
+        - name: time-naming
+        - name: unexported-return
+        - name: indent-error-flow
+        - name: errorf
+        - name: empty-block
+        - name: superfluous-else
+        - name: unreachable-code
+        - name: redefines-builtin-id
+    staticcheck:
+      dot-import-whitelist:
+        - fmt
+        - github.com/onsi/gomega
+        - github.com/onsi/ginkgo/v2
+  exclusions:
+    generated: lax
+    warn-unused: true
+formatters:
+  enable:
+    - goimports # ensures imports are organized
+    - gofmt # Check if the code is formatted according to 'gofmt' command.
+  settings:
+    goimports:
+      # A list of prefixes, which, if set, checks import paths
+      # with the given prefixes are grouped after 3rd-party packages.
+      # Default: []
+      local-prefixes:
+        - github.com/cloudscale-ch/cloudscale-go-sdk
+  exclusions:
+    generated: lax
+    warn-unused: true

Makefile

@@ -1,26 +1,78 @@
 VERSION ?= $(shell cat VERSION)
 TESTARGS?=
 
-test:
+# Get the currently used golang install path (in GOPATH/bin, unless GOBIN is set)
+ifeq (,$(shell go env GOBIN))
+GOBIN=$(shell go env GOPATH)/bin
+else
+GOBIN=$(shell go env GOBIN)
+endif
+
+##@ Dependencies
+
+## Location to install dependencies to
+LOCALBIN := $(shell pwd)/bin
+$(LOCALBIN):
+	mkdir -p "$(LOCALBIN)"
+
+# Host OS/ARCH used to namespace tool binaries in $(LOCALBIN)
+HOST_PLATFORM := $(shell go env GOOS)-$(shell go env GOARCH)
+
+## Tool Binaries
+GOLANGCI_LINT = $(LOCALBIN)/golangci-lint
+GOVULNCHECK ?= $(LOCALBIN)/govulncheck
+
+# Setting SHELL to bash allows bash commands to be executed by recipes.
+# Options are set to exit when a recipe line exits non-zero or a piped command fails.
+SHELL = /usr/bin/env bash -o pipefail
+.SHELLFLAGS = -ec
+
+##@ General
+
+# The help target prints out all targets with their descriptions organized
+# beneath their categories. The categories are represented by '##@' and the
+# target descriptions by '##'. The awk command is responsible for reading the
+# entire set of makefiles included in this invocation, looking for lines of the
+# file as xyz: ## something, and then pretty-format the target and help. Then,
+# if there's a line with ##@ something, that gets pretty-printed as a category.
+# More info on the usage of ANSI control characters for terminal formatting:
+# https://en.wikipedia.org/wiki/ANSI_escape_code#SGR_parameters
+# More info on the awk command:
+# http://linuxcommand.org/lc3_adv_awk.php
+
+.PHONY: help
+help: ## Display this help.
+	@awk 'BEGIN {FS = ":.*##"; printf "\nUsage:\n  make \033[36m<target>\033[0m\n"} /^[a-zA-Z_0-9-]+:.*?##/ { printf "  \033[36m%-15s\033[0m %s\n", $$1, $$2 } /^##@/ { printf "\n\033[1m%s\033[0m\n", substr($$0, 5) } ' $(MAKEFILE_LIST)
+
+##@ Development
+
+.PHONY: test
+test: ## Run unit tests
 	go test -race -v ./... $(TESTARGS) -timeout 30s
 
-clean-testcache:
-	@go clean -testcache  # Force retesting of code
+.PHONY: clean-testcache
+clean-testcache: ## Force retesting of code
+	@go clean -testcache
 
-integration: clean-testcache
+.PHONY: integration
+integration: clean-testcache ## Run integration tests
 	go test -tags=integration -v ./test/integration/... $(TESTARGS) -parallel 4 -timeout 120m
 
-integration-short: clean-testcache
+.PHONY: integration-short
+integration-short: clean-testcache ## Run quick integration tests
 	go test -tags=integration -short -v ./test/integration/... $(TESTARGS) -parallel 4 -timeout 120m
 
-vet:
+.PHONY: vet
+vet: ## Run go vet against code.
 	go vet ./...
 	go vet -tags=integration ./test/integration/
 
-fmt:
+.PHONY: fmt
+fmt: ## Run go fmt against code.
 	go fmt
 	gofmt -l -w test/integration
 
+.PHONY: bump-version
 bump-version:
 	@[ "${NEW_VERSION}" ] || ( echo "NEW_VERSION must be set (ex. make NEW_VERSION=v1.x.x bump-version)"; exit 1 )
 	@(echo ${NEW_VERSION} | grep -E "^v") || ( echo "NEW_VERSION must be a semver ('v' prefix is required)"; exit 1 )
@@ -29,4 +81,56 @@ bump-version:
 	@sed -i.bak -e 's/${VERSION}/${NEW_VERSION}/g' cloudscale.go
 	@rm cloudscale.go.bak
 
-.PHONY: test vet integration integration-short clean-testcache
+.PHONY: lint
+lint: golangci-lint ## Run golangci-lint linter
+	"$(GOLANGCI_LINT)" run
+
+.PHONY: lint-fix
+lint-fix: golangci-lint ## Run golangci-lint linter and perform fixes
+	"$(GOLANGCI_LINT)" run --fix
+
+.PHONY: lint-config
+lint-config: golangci-lint ## Verify golangci-lint linter configuration
+	"$(GOLANGCI_LINT)" config verify
+
+.PHONY: govulncheck
+govulncheck: govulncheck-tool ## Run govulncheck to scan for known, reachable vulnerabilities (incl. stdlib/toolchain).
+	"$(GOVULNCHECK)" ./...
+
+GOLANGCI_LINT_VERSION ?= v2.12.2
+GOVULNCHECK_VERSION ?= v1.5.0
+
+.PHONY: golangci-lint
+golangci-lint: $(GOLANGCI_LINT) ## Download golangci-lint locally if necessary.
+$(GOLANGCI_LINT): $(LOCALBIN)
+	$(call go-install-tool,$(GOLANGCI_LINT),github.com/golangci/golangci-lint/v2/cmd/golangci-lint,$(GOLANGCI_LINT_VERSION))
+	@test -f .custom-gcl.yml && { \
+		echo "Building custom golangci-lint with plugins..." && \
+		$(GOLANGCI_LINT) custom --destination $(LOCALBIN) --name golangci-lint-custom && \
+		mv -f $(LOCALBIN)/golangci-lint-custom $(GOLANGCI_LINT); \
+	} || true
+
+.PHONY: govulncheck-tool
+govulncheck-tool: $(GOVULNCHECK) ## Download govulncheck locally if necessary.
+$(GOVULNCHECK): $(LOCALBIN)
+	$(call go-install-tool,$(GOVULNCHECK),golang.org/x/vuln/cmd/govulncheck,$(GOVULNCHECK_VERSION))
+
+# go-install-tool will 'go install' any package with custom target and name of binary, if it doesn't exist
+# $1 - target path with name of binary
+# $2 - package url which can be installed
+# $3 - specific version of package
+define go-install-tool
+@[ -f "$(1)-$(3)-$(HOST_PLATFORM)" ] && [ "$$(readlink -- "$(1)" 2>/dev/null)" = "$(1)-$(3)-$(HOST_PLATFORM)" ] || { \
+set -e; \
+package=$(2)@$(3) ;\
+echo "Downloading $${package} ($(HOST_PLATFORM))" ;\
+rm -f "$(1)" ;\
+GOBIN="$(LOCALBIN)" go install $${package} ;\
+mv "$(LOCALBIN)/$$(basename "$(1)")" "$(1)-$(3)-$(HOST_PLATFORM)" ;\
+} ;\
+ln -sf "$$(realpath "$(1)-$(3)-$(HOST_PLATFORM)")" "$(1)"
+endef
+
+define gomodver
+$(shell go list -m -f '{{if .Replace}}{{.Replace.Version}}{{else}}{{.Version}}{{end}}' $(1) 2>/dev/null)
+endef

cloudscale.go

@@ -6,7 +6,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"net/url"
 	"os"
@@ -139,7 +138,7 @@ func NewClient(httpClient *http.Client) *Client {
 	return c
 }
 
-func (c *Client) NewRequest(ctx context.Context, method, urlStr string, body interface{}) (*http.Request, error) {
+func (c *Client) NewRequest(ctx context.Context, method, urlStr string, body any) (*http.Request, error) {
 	rel, err := url.Parse(urlStr)
 	if err != nil {
 		return nil, err
@@ -155,7 +154,7 @@ func (c *Client) NewRequest(ctx context.Context, method, urlStr string, body int
 		}
 	}
 
-	req, err := http.NewRequest(method, u.String(), buf)
+	req, err := http.NewRequestWithContext(ctx, method, u.String(), buf)
 	if err != nil {
 		return nil, err
 	}
@@ -171,8 +170,7 @@ func (c *Client) NewRequest(ctx context.Context, method, urlStr string, body int
 	return req, nil
 }
 
-func (c *Client) Do(ctx context.Context, req *http.Request, v interface{}) error {
-
+func (c *Client) Do(ctx context.Context, req *http.Request, v any) error {
 	req = req.WithContext(ctx)
 
 	resp, err := c.client.Do(req)
@@ -213,7 +211,7 @@ func CheckResponse(r *http.Response) error {
 		return nil
 	}
 
-	data, err := ioutil.ReadAll(r.Body)
+	data, err := io.ReadAll(r.Body)
 	res := map[string]string{}
 	if err == nil && len(data) > 0 {
 		err := json.Unmarshal(data, &res)

cloudscale_test.go

@@ -3,7 +3,7 @@ package cloudscale
 import (
 	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
@@ -40,6 +40,7 @@ func teardown() {
 }
 
 func testHTTPMethod(t *testing.T, r *http.Request, expected string) {
+	t.Helper()
 	if expected != r.Method {
 		t.Errorf("Request method = %v, expected %v", r.Method, expected)
 	}
@@ -55,7 +56,6 @@ func TestNewClient(t *testing.T) {
 	if c.UserAgent != userAgent {
 		t.Errorf("NewClient UserAgent = %v, expected %v", c.UserAgent, userAgent)
 	}
-
 }
 
 func TestNewRequest(t *testing.T) {
@@ -73,7 +73,7 @@ func TestNewRequest(t *testing.T) {
 	}
 
 	// test body was JSON encoded
-	body, _ := ioutil.ReadAll(req.Body)
+	body, _ := io.ReadAll(req.Body)
 	if string(body) != outBody {
 		t.Errorf("NewRequest(%v)Body = %v, expected %v", inBody, string(body), outBody)
 	}
@@ -115,7 +115,7 @@ func TestCheckResponse(t *testing.T) {
 	res := &http.Response{
 		Request:    &http.Request{},
 		StatusCode: http.StatusBadRequest,
-		Body:       ioutil.NopCloser(strings.NewReader(`{"name": "This field may not be blank."}`)),
+		Body:       io.NopCloser(strings.NewReader(`{"name": "This field may not be blank."}`)),
 	}
 	err := CheckResponse(res).(*ErrorResponse)
 
@@ -146,7 +146,7 @@ func TestDo(t *testing.T) {
 		if m := http.MethodGet; m != r.Method {
 			t.Errorf("Request method = %v, expected %v", r.Method, m)
 		}
-		fmt.Fprint(w, `{"A":"a"}`)
+		_, _ = fmt.Fprint(w, `{"A":"a"}`)
 	})
 
 	req, _ := client.NewRequest(ctx, http.MethodGet, "/", nil)
@@ -167,7 +167,7 @@ func TestDo_httpError(t *testing.T) {
 	defer teardown()
 
 	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
-		http.Error(w, "Bad Request", 400)
+		http.Error(w, "Bad Request", http.StatusBadRequest)
 	})
 
 	req, _ := client.NewRequest(ctx, http.MethodGet, "/", nil)
@@ -200,7 +200,7 @@ func TestDo_redirectLoop(t *testing.T) {
 }
 
 // TODO: Maybe add an argument with a description for the assertion.
-func assertEqual(t *testing.T, expected interface{}, actual interface{}) {
+func assertEqual(t *testing.T, expected any, actual any) {
 	t.Helper()
 
 	if !reflect.DeepEqual(expected, actual) {