Replace deprecated io/ioutil with modern os/io equivalents

Replaces all ioutil.ReadFile, WriteFile, ReadDir, TempDir, TempFile,
ReadAll and Discard calls with their Go 1.16+ replacements in os and io
packages. Also removes deprecated rand.Seed(time.Now().UnixNano()) from
randomString() (deprecated since Go 1.20) and removes the now-unused
time import.

Author: ramonskie

src/nginx/supply/supply.go

@@ -5,15 +5,13 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math/rand"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"regexp"
 	"sort"
 	"strings"
-	"time"
 
 	"github.com/cloudfoundry/libbuildpack"
 )
@@ -180,7 +178,7 @@ func (s *Supplier) ValidateNginxConf() error {
 }
 
 func (s *Supplier) CheckAccessLogging() error {
-	contents, err := ioutil.ReadFile(filepath.Join(s.Stager.BuildDir(), "nginx.conf"))
+	contents, err := os.ReadFile(filepath.Join(s.Stager.BuildDir(), "nginx.conf"))
 	if err != nil {
 		return err
 	}
@@ -238,7 +236,7 @@ func (s *Supplier) InstallOpenResty() error {
 }
 
 func (s *Supplier) validateNginxConfHasPort() error {
-	tmpDir, err := ioutil.TempDir("", "")
+	tmpDir, err := os.MkdirTemp("", "")
 	if err != nil {
 		return fmt.Errorf("failed to create temp dir: %w", err)
 	}
@@ -257,7 +255,7 @@ func (s *Supplier) validateNginxConfHasPort() error {
 		return fmt.Errorf("varify command failed: %w\noutput: %s", err, string(output))
 	}
 
-	confContents, err := ioutil.ReadFile(nginxConfPath)
+	confContents, err := os.ReadFile(nginxConfPath)
 	if err != nil {
 		return fmt.Errorf("error reading temp config file: %w", err)
 	}
@@ -270,7 +268,7 @@ func (s *Supplier) validateNginxConfHasPort() error {
 		if !filepath.IsAbs(confFile) {
 			confFile = filepath.Join(tmpDir, confFile)
 		}
-		contents, err := ioutil.ReadFile(confFile)
+		contents, err := os.ReadFile(confFile)
 		if err != nil {
 			return fmt.Errorf("error reading temp config file %s: %w", confFile, err)
 		}
@@ -288,8 +286,6 @@ func (s *Supplier) validateNginxConfHasPort() error {
 }
 
 func randomString(strLength int) string {
-	rand.Seed(time.Now().UnixNano())
-
 	const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
 	const numCharsPossible = len(letters)
 	randString := ""
@@ -302,7 +298,7 @@ func randomString(strLength int) string {
 }
 
 func (s *Supplier) validateNGINXConfSyntax() error {
-	tmpConfDir, err := ioutil.TempDir("/tmp", "conf")
+	tmpConfDir, err := os.MkdirTemp("/tmp", "conf")
 	if err != nil {
 		return fmt.Errorf("Error creating temp nginx conf dir: %s", err.Error())
 	}
@@ -318,8 +314,8 @@ func (s *Supplier) validateNGINXConfSyntax() error {
 	buildpackYMLPath := filepath.Join(s.Stager.BuildDir(), "buildpack.yml")
 	cmd := exec.Command(filepath.Join(s.Stager.DepDir(), "bin", "varify"), "-buildpack-yml-path", buildpackYMLPath, nginxConfPath, localModulePath, globalModulePath)
 	cmd.Dir = tmpConfDir
-	cmd.Stdout = ioutil.Discard
-	cmd.Stderr = ioutil.Discard
+	cmd.Stdout = io.Discard
+	cmd.Stderr = io.Discard
 	cmd.Env = append(os.Environ(), "PORT=8080")
 	if err := s.Command.Run(cmd); err != nil {
 		return err

src/nginx/supply/supply_test.go

@@ -3,7 +3,6 @@ package supply_test
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	exec "os/exec"
 	"path/filepath"
@@ -41,7 +40,7 @@ var _ = Describe("Supply", func() {
 		mockManifest = NewMockManifest(mockCtrl)
 		mockInstaller = NewMockInstaller(mockCtrl)
 		mockCommand = NewMockCommand(mockCtrl)
-		depDir, err = ioutil.TempDir("", "nginx.depdir")
+		depDir, err = os.MkdirTemp("", "nginx.depdir")
 		Expect(err).ToNot(HaveOccurred())
 		mockStager.EXPECT().DepDir().AnyTimes().Return(depDir)
 		supplier = supply.New(mockStager, mockManifest, mockInstaller, logger, mockCommand)
@@ -207,7 +206,7 @@ var _ = Describe("Supply", func() {
 		)
 
 		BeforeEach(func() {
-			buildDir, err = ioutil.TempDir("", "")
+			buildDir, err = os.MkdirTemp("", "")
 			Expect(err).NotTo(HaveOccurred())
 
 			mockStager.EXPECT().BuildDir().Return(buildDir).AnyTimes()
@@ -221,7 +220,7 @@ var _ = Describe("Supply", func() {
 
 		It("calls varify to parse the port", func() {
 			nginxConfPath := filepath.Join(buildDir, "nginx.conf")
-			err := ioutil.WriteFile(nginxConfPath, []byte("{{port}}"), 0666)
+			err := os.WriteFile(nginxConfPath, []byte("{{port}}"), 0666)
 			Expect(err).NotTo(HaveOccurred())
 
 			mockCommand.EXPECT().
@@ -240,7 +239,7 @@ var _ = Describe("Supply", func() {
 		Context("app's nginx.conf is missing {{port}}", func() {
 			It("logs error stating {{port}} is missing", func() {
 				nginxConfPath := filepath.Join(buildDir, "nginx.conf")
-				err := ioutil.WriteFile(nginxConfPath, []byte("FOOBAR"), 0666)
+				err := os.WriteFile(nginxConfPath, []byte("FOOBAR"), 0666)
 				Expect(err).NotTo(HaveOccurred())
 				mockCommand.EXPECT().RunWithOutput(gomock.Any())
 				err = supplier.ValidateNginxConf()
@@ -256,31 +255,31 @@ var _ = Describe("Supply", func() {
 			})
 
 			It("logs a warning when access logging is not set", func() {
-				ioutil.WriteFile(filepath.Join(buildDir, "nginx.conf"), []byte("some content"), 0666)
+				os.WriteFile(filepath.Join(buildDir, "nginx.conf"), []byte("some content"), 0666)
 				Expect(supplier.CheckAccessLogging()).To(Succeed())
 				Expect(buffer.String()).To(ContainSubstring("Warning: access logging is turned off in your nginx.conf file, this may make your app difficult to debug."))
 			})
 
 			It("logs a warning when access logging is set to off", func() {
-				ioutil.WriteFile(filepath.Join(buildDir, "nginx.conf"), []byte("access_log off"), 0666)
+				os.WriteFile(filepath.Join(buildDir, "nginx.conf"), []byte("access_log off"), 0666)
 				Expect(supplier.CheckAccessLogging()).To(Succeed())
 				Expect(buffer.String()).To(ContainSubstring("Warning: access logging is turned off in your nginx.conf file, this may make your app difficult to debug."))
 			})
 
 			It("logs a warning when access logging is set to off with extra spaces", func() {
-				ioutil.WriteFile(filepath.Join(buildDir, "nginx.conf"), []byte("access_log    off"), 0666)
+				os.WriteFile(filepath.Join(buildDir, "nginx.conf"), []byte("access_log    off"), 0666)
 				Expect(supplier.CheckAccessLogging()).To(Succeed())
 				Expect(buffer.String()).To(ContainSubstring("Warning: access logging is turned off in your nginx.conf file, this may make your app difficult to debug."))
 			})
 
 			It("logs a warning when access logging is set to OFF", func() {
-				ioutil.WriteFile(filepath.Join(buildDir, "nginx.conf"), []byte("access_log OFF"), 0666)
+				os.WriteFile(filepath.Join(buildDir, "nginx.conf"), []byte("access_log OFF"), 0666)
 				Expect(supplier.CheckAccessLogging()).To(Succeed())
 				Expect(buffer.String()).To(ContainSubstring("Warning: access logging is turned off in your nginx.conf file, this may make your app difficult to debug."))
 			})
 
 			It("logs a warning when access logging is set to a path", func() {
-				ioutil.WriteFile(filepath.Join(buildDir, "nginx.conf"), []byte("access_log /some/path"), 0666)
+				os.WriteFile(filepath.Join(buildDir, "nginx.conf"), []byte("access_log /some/path"), 0666)
 				Expect(supplier.CheckAccessLogging()).To(Succeed())
 				Expect(buffer.String()).ToNot(ContainSubstring("Warning: access logging is turned off in your nginx.conf file, this may make your app difficult to debug."))
 			})

src/nginx/varify/cli/varify.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	htmlTemplate "html/template"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
@@ -48,7 +47,7 @@ func main() {
 			"The default nameservers %s will be used. Error: %s", resolvConfPath, defaultNameServer, err)
 	}
 
-	body, err := ioutil.ReadFile(filename)
+	body, err := os.ReadFile(filename)
 	if err != nil {
 		log.Fatalf("Could not read config file: %s: %s", filename, err)
 	}
@@ -108,7 +107,7 @@ func main() {
 			if !filepath.IsAbs(confFile) {
 				confFile = filepath.Join(filepath.Dir(filename), confFile)
 			}
-			str, err = ioutil.ReadFile(confFile)
+			str, err = os.ReadFile(confFile)
 			if err != nil {
 				log.Fatalf("Could not read config file: %s: %s", filename, err)
 			}
@@ -169,7 +168,7 @@ func getPlaintextEnvVars(bpYMLPath string) ([]string, error) {
 		return []string{}, nil
 	}
 
-	bpYMLContents, err := ioutil.ReadFile(bpYMLPath)
+	bpYMLContents, err := os.ReadFile(bpYMLPath)
 	if err != nil {
 		return []string{}, err
 	}

src/nginx/varify/cli/varify_suite_test.go

@@ -1,7 +1,6 @@
 package main_test
 
 import (
-	"io/ioutil"
 	"os/exec"
 	"path/filepath"
 	"testing"
@@ -28,7 +27,7 @@ var _ = AfterSuite(func() {
 })
 
 func runCli(tmpDir, body string, env []string, localModulePath, globalModulePath string, resolveConfPath string, defaultNameServer string, bpYMLPath string, expectedExitcode int) (string, *gexec.Session) {
-	Expect(ioutil.WriteFile(filepath.Join(tmpDir, "nginx.conf"), []byte(body), 0644)).To(Succeed())
+	Expect(os.WriteFile(filepath.Join(tmpDir, "nginx.conf"), []byte(body), 0644)).To(Succeed())
 	args := []string{filepath.Join(tmpDir, "nginx.conf"), localModulePath, globalModulePath, resolveConfPath, defaultNameServer}
 	if bpYMLPath != "" {
 		args = append([]string{"-buildpack-yml-path", bpYMLPath}, args...)
@@ -40,7 +39,7 @@ func runCli(tmpDir, body string, env []string, localModulePath, globalModulePath
 	Expect(err).ToNot(HaveOccurred())
 	Eventually(session).Should(gexec.Exit(expectedExitcode))
 
-	output, err := ioutil.ReadFile(filepath.Join(tmpDir, "nginx.conf"))
+	output, err := os.ReadFile(filepath.Join(tmpDir, "nginx.conf"))
 	Expect(err).ToNot(HaveOccurred())
 
 	return string(output), session

src/nginx/varify/cli/varify_test.go

@@ -2,7 +2,6 @@ package main_test
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 
@@ -18,7 +17,7 @@ var _ = Describe("varify", func() {
 
 	BeforeEach(func() {
 		var err error
-		tmpDir, err = ioutil.TempDir("", "nginx.tmpdir")
+		tmpDir, err = os.MkdirTemp("", "nginx.tmpdir")
 		Expect(err).ToNot(HaveOccurred())
 	})
 
@@ -47,7 +46,7 @@ nginx:
     - "FOO"
 `
 			defer os.RemoveAll(bpYMLPath)
-			Expect(ioutil.WriteFile(bpYMLPath, []byte(contents), os.ModePerm)).To(Succeed())
+			Expect(os.WriteFile(bpYMLPath, []byte(contents), os.ModePerm)).To(Succeed())
 			body, _ := runCli(tmpDir, textBody, []string{`FOO={"abcd":1234}`}, "", "", "", "", bpYMLPath, 0)
 			Expect(body).To(Equal(`The env var FOO is {"abcd":1234}`))
 		})
@@ -62,11 +61,11 @@ nginx:
 		listen       {{port}};
 	}
 `
-				Expect(ioutil.WriteFile(filepath.Join(tmpDir, "custom.conf"), []byte(customConfStr), os.ModePerm)).To(Succeed())
+				Expect(os.WriteFile(filepath.Join(tmpDir, "custom.conf"), []byte(customConfStr), os.ModePerm)).To(Succeed())
 				body, _ := runCli(tmpDir, nginxConfStr, []string{"PORT=8080"}, "", "", "", "", "", 0)
 				Expect(body).To(Equal(nginxConfStr))
 
-				contents, err := ioutil.ReadFile(filepath.Join(tmpDir, "custom.conf"))
+				contents, err := os.ReadFile(filepath.Join(tmpDir, "custom.conf"))
 				Expect(err).NotTo(HaveOccurred())
 				Expect(string(contents)).To(Equal(`
   server {
@@ -83,8 +82,8 @@ nginx:
 
 				Expect(os.Mkdir(localModulePath, 0744)).To(Succeed())
 				Expect(os.Mkdir(globalModulePath, 0744)).To(Succeed())
-				Expect(ioutil.WriteFile(filepath.Join(localModulePath, "local.so"), []byte("dummy data"), 0644)).To(Succeed())
-				Expect(ioutil.WriteFile(filepath.Join(globalModulePath, "global.so"), []byte("dummy data"), 0644)).To(Succeed())
+				Expect(os.WriteFile(filepath.Join(localModulePath, "local.so"), []byte("dummy data"), 0644)).To(Succeed())
+				Expect(os.WriteFile(filepath.Join(globalModulePath, "global.so"), []byte("dummy data"), 0644)).To(Succeed())
 			})
 
 			Context("when the module is in local modules directory", func() {
@@ -109,28 +108,28 @@ nginx:
 
 			It("reads nameservers from the simple resolv-conf file", func() {
 				var resolvConfPath = filepath.Join(tmpDir, "resolv-simple.conf")
-				Expect(ioutil.WriteFile(resolvConfPath, []byte("nameserver "+nameserver1), 0644)).To(Succeed())
+				Expect(os.WriteFile(resolvConfPath, []byte("nameserver "+nameserver1), 0644)).To(Succeed())
 				body, _ := runCli(tmpDir, "Hi the nameservers are {{nameservers}}.", nil, "", "", resolvConfPath, defaultNameServer, "", 0)
 				Expect(body).To(Equal("Hi the nameservers are " + nameserver1 + "."))
 			})
 
 			It("reads nameservers from the unusual resolv-conf file", func() {
 				var resolvConfPath = filepath.Join(tmpDir, "resolv-unusual.conf")
-				Expect(ioutil.WriteFile(resolvConfPath, []byte("# comment 1\n  \t  nameserver "+nameserver1+"  \t  \n# comment 2"), 0644)).To(Succeed())
+				Expect(os.WriteFile(resolvConfPath, []byte("# comment 1\n  \t  nameserver "+nameserver1+"  \t  \n# comment 2"), 0644)).To(Succeed())
 				body, _ := runCli(tmpDir, "Hi the nameservers are {{nameservers}}.", nil, "", "", resolvConfPath, defaultNameServer, "", 0)
 				Expect(body).To(Equal("Hi the nameservers are " + nameserver1 + "."))
 			})
 
 			It("reads nameservers from the resolv-conf file with multiple entries", func() {
 				var resolvConfPath = filepath.Join(tmpDir, "resolv-multiple.conf")
-				Expect(ioutil.WriteFile(resolvConfPath, []byte("nameserver "+nameserver1+"\nnameserver "+nameserver2), 0644)).To(Succeed())
+				Expect(os.WriteFile(resolvConfPath, []byte("nameserver "+nameserver1+"\nnameserver "+nameserver2), 0644)).To(Succeed())
 				body, _ := runCli(tmpDir, "Hi the nameservers are {{nameservers}}.", nil, "", "", resolvConfPath, defaultNameServer, "", 0)
 				Expect(body).To(Equal("Hi the nameservers are " + nameserver1 + " " + nameserver2 + "."))
 			})
 
 			It("set the default nameservers if the resolv-conf file is empty", func() {
 				var resolvConfPath = filepath.Join(tmpDir, "resolv-empty.conf")
-				Expect(ioutil.WriteFile(resolvConfPath, []byte(""), 666)).To(Succeed())
+				Expect(os.WriteFile(resolvConfPath, []byte(""), 666)).To(Succeed())
 				body, _ := runCli(tmpDir, "Hi the nameservers are {{nameservers}}.", nil, "", "", resolvConfPath, defaultNameServer, "", 0)
 				Expect(body).To(Equal("Hi the nameservers are " + defaultNameServer + "."))
 			})