migrate ioutil calls to io,os calls (#911)

The Go 1.19 and nearby versions marked these calls as deprecated. Clean
them up with their documented replacements.

Ran these commands to fix it up:

```
$ gofmt -w -r 'ioutil.TempFile -> os.CreateTemp' $(find . -type f -name '*.go'| grep -v "/vendor/")
$ gofmt -w -r 'ioutil.ReadAll -> io.ReadAll' $(find . -type f -name '*.go'| grep -v "/vendor/")
$ gofmt -w -r 'ioutil.WriteFile -> os.WriteFile' $(find . -type f -name '*.go'| grep -v "/vendor/")
$ gofmt -w -r 'ioutil.TempDir -> os.MkdirTemp' $(find . -type f -name '*.go'| grep -v "/vendor/")
```

Then removing the `ioutil` import from the files that no longer use it.

Oh, also ha to revert some gofmt changes in `verifier/contentsignature`
that I'll ship separately.

errors.go

@@ -9,7 +9,6 @@ package main
 import (
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 
 	log "github.com/sirupsen/logrus"
@@ -30,7 +29,7 @@ func httpError(w http.ResponseWriter, r *http.Request, errorCode int, errorMessa
 	// request body is read before writing a response.
 	// https://github.com/golang/go/issues/15789
 	if r.Body != nil {
-		io.Copy(ioutil.Discard, r.Body)
+		io.Copy(io.Discard, r.Body)
 		r.Body.Close()
 	}
 	http.Error(w, msg, errorCode)

handlers.go

@@ -12,7 +12,7 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"os"
 	"path"
@@ -90,7 +90,7 @@ func (a *autographer) handleSignature(w http.ResponseWriter, r *http.Request) {
 		httpError(w, r, http.StatusUnauthorized, "authorization verification failed: %v", err)
 		return
 	}
-	body, err := ioutil.ReadAll(r.Body)
+	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		httpError(w, r, http.StatusBadRequest, "failed to read request body: %s", err)
 		return
@@ -453,7 +453,7 @@ func (a *autographer) handleGetAuthKeyIDs(w http.ResponseWriter, r *http.Request
 		return
 	}
 	if r.Body != nil {
-		body, err := ioutil.ReadAll(r.Body)
+		body, err := io.ReadAll(r.Body)
 		if err != nil {
 			httpError(w, r, http.StatusBadRequest, "failed to read request body: %s", err)
 			return

handlers_test.go

@@ -16,7 +16,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"hash"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/http/httptest"
@@ -836,7 +836,7 @@ func verifyAPKSignature(signedAPK []byte) error {
 			if err != nil {
 				return err
 			}
-			sigdata, err = ioutil.ReadAll(rc)
+			sigdata, err = io.ReadAll(rc)
 			if err != nil {
 				return err
 			}
@@ -849,7 +849,7 @@ func verifyAPKSignature(signedAPK []byte) error {
 			if err != nil {
 				return err
 			}
-			rawsig, err := ioutil.ReadAll(rc)
+			rawsig, err := io.ReadAll(rc)
 			if err != nil {
 				return err
 			}

main.go

@@ -12,7 +12,6 @@ import (
 	"crypto/sha256"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"net/http"
 	"os"
 	"os/signal"
@@ -254,7 +253,7 @@ func (c *configuration) loadFromFile(path string) error {
 		confSHA        [32]byte
 		err            error
 	)
-	data, err = ioutil.ReadFile(path)
+	data, err = os.ReadFile(path)
 	if err != nil {
 		return err
 	}

main_test.go

@@ -8,7 +8,6 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"testing"
 	"time"
@@ -197,7 +196,7 @@ authorizations:
 	for i, testcase := range testcases {
 		var conf configuration
 		// write conf file to /tmp and read it back
-		fd, err := ioutil.TempFile("", "autographtestconf")
+		fd, err := os.CreateTemp("", "autographtestconf")
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -228,7 +227,7 @@ func TestDuplicateSigners(t *testing.T) {
 
 	var conf configuration
 	// write conf file to /tmp and read it back
-	fd, err := ioutil.TempFile("", "autographtestconf")
+	fd, err := os.CreateTemp("", "autographtestconf")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -283,7 +282,7 @@ func TestDuplicateAuthorization(t *testing.T) {
 
 	var conf configuration
 	// write conf file to /tmp and read it back
-	fd, err := ioutil.TempFile("", "autographtestconf")
+	fd, err := os.CreateTemp("", "autographtestconf")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -353,7 +352,7 @@ func TestUnknownSignerInAuthorization(t *testing.T) {
 
 	var conf configuration
 	// write conf file to /tmp and read it back
-	fd, err := ioutil.TempFile("", "autographtestconf")
+	fd, err := os.CreateTemp("", "autographtestconf")
 	if err != nil {
 		t.Fatal(err)
 	}

signer/apk2/apk2.go

@@ -3,7 +3,6 @@ package apk2
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 
 	"crypto/ecdsa"
 	"crypto/sha256"
@@ -111,35 +110,35 @@ func (s *APK2Signer) Config() signer.Configuration {
 
 // SignFile signs a whole aligned APK file with v1 and v2 signatures
 func (s *APK2Signer) SignFile(file []byte, options interface{}) (signer.SignedFile, error) {
-	keyPath, err := ioutil.TempFile("", fmt.Sprintf("apk2_%s.key", s.ID))
+	keyPath, err := os.CreateTemp("", fmt.Sprintf("apk2_%s.key", s.ID))
 	if err != nil {
 		return nil, fmt.Errorf("apk2: failed to create tempfile with private key: %w", err)
 	}
 	defer os.Remove(keyPath.Name())
-	err = ioutil.WriteFile(keyPath.Name(), []byte(s.pkcs8Key), 0400)
+	err = os.WriteFile(keyPath.Name(), []byte(s.pkcs8Key), 0400)
 	if err != nil {
 		return nil, fmt.Errorf("apk2: failed to write private key to tempfile: %w", err)
 	}
 
-	certPath, err := ioutil.TempFile("", fmt.Sprintf("apk2_%s.cert", s.ID))
+	certPath, err := os.CreateTemp("", fmt.Sprintf("apk2_%s.cert", s.ID))
 	if err != nil {
 		return nil, fmt.Errorf("apk2: failed to create tempfile for input to sign: %w", err)
 	}
 	defer os.Remove(certPath.Name())
-	err = ioutil.WriteFile(certPath.Name(), []byte(s.Certificate), 0400)
+	err = os.WriteFile(certPath.Name(), []byte(s.Certificate), 0400)
 	if err != nil {
 		return nil, fmt.Errorf("apk2: failed to write public cert to tempfile: %w", err)
 	}
 
 	// write the input to a temp file
 	h := sha256.New()
 	h.Write(file)
-	tmpAPKFile, err := ioutil.TempFile("", fmt.Sprintf("apk2_input_%x.apk", h.Sum(nil)))
+	tmpAPKFile, err := os.CreateTemp("", fmt.Sprintf("apk2_input_%x.apk", h.Sum(nil)))
 	if err != nil {
 		return nil, fmt.Errorf("apk2: failed to create tempfile for input to sign: %w", err)
 	}
 	defer os.Remove(tmpAPKFile.Name())
-	err = ioutil.WriteFile(tmpAPKFile.Name(), file, 0755)
+	err = os.WriteFile(tmpAPKFile.Name(), file, 0755)
 	if err != nil {
 		return nil, fmt.Errorf("apk2: failed to write tempfile for input to sign: %w", err)
 	}
@@ -169,7 +168,7 @@ func (s *APK2Signer) SignFile(file []byte, options interface{}) (signer.SignedFi
 	}
 	log.Debugf("signed as:\n%s\n", string(out))
 
-	signedApk, err := ioutil.ReadFile(tmpAPKFile.Name())
+	signedApk, err := os.ReadFile(tmpAPKFile.Name())
 	if err != nil {
 		return nil, fmt.Errorf("apk2: failed to read signed file: %w", err)
 	}

signer/apk2/apk2_test.go

@@ -1,12 +1,12 @@
 package apk2
 
 import (
-	"github.com/mozilla-services/autograph/signer"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"strings"
 	"testing"
+
+	"github.com/mozilla-services/autograph/signer"
 )
 
 func assertNewSignerWithConfOK(t *testing.T, conf signer.Configuration) *APK2Signer {
@@ -177,12 +177,12 @@ func TestSignFile(t *testing.T) {
 		t.Parallel()
 
 		// write the signature to a temp file
-		tmpApk, err := ioutil.TempFile("", "apk2_TestSignedApkFile")
+		tmpApk, err := os.CreateTemp("", "apk2_TestSignedApkFile")
 		if err != nil {
 			t.Fatal(err)
 		}
 		defer os.Remove(tmpApk.Name())
-		err = ioutil.WriteFile(tmpApk.Name(), signedFile, 0755)
+		err = os.WriteFile(tmpApk.Name(), signedFile, 0755)
 		if err != nil {
 			t.Fatalf("error writing file %s: %q", tmpApk.Name(), err)
 		}

signer/contentsignaturepki/upload.go

@@ -4,7 +4,7 @@ import (
 	"crypto/sha256"
 	"crypto/x509"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/url"
 	"os"
@@ -63,7 +63,7 @@ func writeLocalFile(data, name string, target *url.URL) error {
 		}
 	}
 	// write the file into the target dir
-	return ioutil.WriteFile(target.Path+name, []byte(data), 0755)
+	return os.WriteFile(target.Path+name, []byte(data), 0755)
 }
 
 // buildHTTPClient returns the default HTTP.Client for fetching X5Us
@@ -95,7 +95,7 @@ func GetX5U(client *http.Client, x5u string) (body []byte, certs []*x509.Certifi
 		err = fmt.Errorf("failed to retrieve x5u from %s: %s", x5u, resp.Status)
 		return
 	}
-	body, err = ioutil.ReadAll(resp.Body)
+	body, err = io.ReadAll(resp.Body)
 	if err != nil {
 		err = fmt.Errorf("failed to parse x5u body: %w", err)
 		return

signer/gpg2/gpg2.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -158,13 +157,13 @@ func createKeyRing(s *GPG2Signer) (dir string, err error) {
 	// reuse keyring in tempdir
 	prefix := fmt.Sprintf("autograph_%s_%s_%s_", s.Type, s.KeyID, s.Mode)
 
-	dir, err = ioutil.TempDir("", prefix)
+	dir, err = os.MkdirTemp("", prefix)
 	if err != nil {
 		return "", fmt.Errorf("gpg2: error creating tempdir for keyring: %w", err)
 	}
 
 	// write the public key to a temp file in our signer's temp dir
-	tmpPublicKeyFile, err := ioutil.TempFile(dir, "gpg2_publickey")
+	tmpPublicKeyFile, err := os.CreateTemp(dir, "gpg2_publickey")
 	if err != nil {
 		err = fmt.Errorf("gpg2: error creating tempfile for public key: %w", err)
 		return "", err
@@ -177,14 +176,14 @@ func createKeyRing(s *GPG2Signer) (dir string, err error) {
 		}
 	}()
 
-	err = ioutil.WriteFile(tmpPublicKeyFile.Name(), []byte(s.PublicKey), 0755)
+	err = os.WriteFile(tmpPublicKeyFile.Name(), []byte(s.PublicKey), 0755)
 	if err != nil {
 		err = fmt.Errorf("gpg2: error writing public key to tempfile: %w", err)
 		return "", err
 	}
 
 	// write the private key to a temp file in our signer's temp dir
-	tmpPrivateKeyFile, err := ioutil.TempFile(dir, "gpg2_privatekey")
+	tmpPrivateKeyFile, err := os.CreateTemp(dir, "gpg2_privatekey")
 	if err != nil {
 		err = fmt.Errorf("gpg2: error creating tempfile for private key: %w", err)
 		return "", err
@@ -196,7 +195,7 @@ func createKeyRing(s *GPG2Signer) (dir string, err error) {
 			err = fmt.Errorf("gpg2: error removing temp private key file %q %w", tmpPrivateKeyFile.Name(), cleanErr)
 		}
 	}()
-	err = ioutil.WriteFile(tmpPrivateKeyFile.Name(), []byte(s.PrivateKey), 0755)
+	err = os.WriteFile(tmpPrivateKeyFile.Name(), []byte(s.PrivateKey), 0755)
 	if err != nil {
 		err = fmt.Errorf("gpg2: error writing private key to tempfile: %w", err)
 		return "", err
@@ -253,7 +252,7 @@ func writeGPGConf(gpgHomeDir string) error {
 	gpgConfPath := filepath.Join(gpgHomeDir, gpgConfFilename)
 	gpgConfContents := fmt.Sprintf("%s\nkeyring %s\nhomedir %s\n", gpgConfContentsHead, keyRingPath, gpgHomeDir)
 
-	err := ioutil.WriteFile(gpgConfPath, []byte(gpgConfContents), 0600)
+	err := os.WriteFile(gpgConfPath, []byte(gpgConfContents), 0600)
 	if err != nil {
 		return err
 	}
@@ -290,7 +289,7 @@ func (s *GPG2Signer) SignData(data []byte, options interface{}) (signer.Signatur
 	keyRingPath := filepath.Join(s.tmpDir, keyRingFilename)
 
 	// write the input to a temp file
-	tmpContentFile, err := ioutil.TempFile(s.tmpDir, fmt.Sprintf("gpg2_%s_input", s.ID))
+	tmpContentFile, err := os.CreateTemp(s.tmpDir, fmt.Sprintf("gpg2_%s_input", s.ID))
 	if err != nil {
 		return nil, fmt.Errorf("gpg2: failed to create tempfile for input to sign: %w", err)
 	}
@@ -299,7 +298,7 @@ func (s *GPG2Signer) SignData(data []byte, options interface{}) (signer.Signatur
 			log.Warnf("gpg2: error removing content file %q: %q", tmpContentFile.Name(), err)
 		}
 	}()
-	err = ioutil.WriteFile(tmpContentFile.Name(), data, 0755)
+	err = os.WriteFile(tmpContentFile.Name(), data, 0755)
 	if err != nil {
 		return nil, fmt.Errorf("gpg2: failed to write tempfile for input to sign: %w", err)
 	}
@@ -384,7 +383,7 @@ func (s *GPG2Signer) SignFiles(inputs []signer.NamedUnsignedFile, options interf
 	}
 
 	// create a tmp dir outside the signer GPG home
-	inputsTmpDir, err := ioutil.TempDir("", fmt.Sprintf("autograph_%s_%s_%s_sign_files", s.Type, s.KeyID, s.Mode))
+	inputsTmpDir, err := os.MkdirTemp("", fmt.Sprintf("autograph_%s_%s_%s_sign_files", s.Type, s.KeyID, s.Mode))
 	if err != nil {
 		err = fmt.Errorf("gpg2: error creating tempdir for debsign: %w", err)
 		return
@@ -403,7 +402,7 @@ func (s *GPG2Signer) SignFiles(inputs []signer.NamedUnsignedFile, options interf
 			return nil, fmt.Errorf("gpg2: cannot sign file %d. Files missing extension .buildinfo, .dsc, or .changes", i)
 		}
 		inputFilePath := filepath.Join(inputsTmpDir, input.Name)
-		err := ioutil.WriteFile(inputFilePath, input.Bytes, 0644)
+		err := os.WriteFile(inputFilePath, input.Bytes, 0644)
 		if err != nil {
 			return nil, fmt.Errorf("gpg2: failed to write tempfile %d for debsign to sign: %w", i, err)
 		}
@@ -449,7 +448,7 @@ func (s *GPG2Signer) SignFiles(inputs []signer.NamedUnsignedFile, options interf
 
 	// read the signed tempfiles
 	for i, inputFilePath := range inputFilePaths {
-		signedFileBytes, err := ioutil.ReadFile(inputFilePath)
+		signedFileBytes, err := os.ReadFile(inputFilePath)
 		if err != nil {
 			return nil, fmt.Errorf("gpg2: failed to read %d %q signed by debsign: %w", i, inputFilePath, err)
 		}