lint: remove depreciated io/ioutil

As of Go 1.16, functionality provided in io/ioutil has been depreciated
in favour of the io or os packages. Now that Go has been
upgraded in go.mod, the linter will not pass without these changes.

aperture.go

@@ -6,7 +6,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -414,7 +413,7 @@ func getConfig() (*Config, error) {
 
 	// Read our config file, either from the custom path provided or our
 	// default location.
-	b, err := ioutil.ReadFile(configFile)
+	b, err := os.ReadFile(configFile)
 	switch {
 	// If the file was found, unmarshal it.
 	case err == nil:

hashmail_server.go

@@ -5,7 +5,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"sync"
 	"time"
 
@@ -100,7 +99,7 @@ func (r *readStream) ReadNextMsg(ctx context.Context) ([]byte, error) {
 	// reader, then read all the encoded bytes until the EOF is emitted by
 	// the reader.
 	msgReader := io.LimitReader(reader, int64(msgLen))
-	return ioutil.ReadAll(msgReader)
+	return io.ReadAll(msgReader)
 }
 
 // ReturnStream gives up the read stream by passing it back up through the

lsat/store.go

@@ -3,7 +3,6 @@ package lsat
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -113,7 +112,7 @@ func (f *FileStore) AllTokens() (map[string]*Token, error) {
 	// just one token, either pending or paid.
 	// TODO(guggero): Update comment once tokens expire and we keep backups.
 	tokenDir := filepath.Dir(f.fileName)
-	files, err := ioutil.ReadDir(tokenDir)
+	files, err := os.ReadDir(tokenDir)
 	if err != nil {
 		return nil, err
 	}
@@ -156,7 +155,7 @@ func (f *FileStore) StoreToken(newToken *Token) error {
 		if newToken.isPending() {
 			newFileName = f.fileNamePending
 		}
-		return ioutil.WriteFile(newFileName, bytes, 0600)
+		return os.WriteFile(newFileName, bytes, 0600)
 
 	// Fail on any other error.
 	case err != nil:
@@ -173,7 +172,7 @@ func (f *FileStore) StoreToken(newToken *Token) error {
 
 		// Write the new token first, so we still have the pending
 		// around if something goes wrong.
-		err := ioutil.WriteFile(f.fileName, bytes, 0600)
+		err := os.WriteFile(f.fileName, bytes, 0600)
 		if err != nil {
 			return err
 		}
@@ -206,7 +205,7 @@ func (f *FileStore) RemovePendingToken() error {
 
 // readTokenFile reads a single token from a file and returns it deserialized.
 func readTokenFile(tokenFile string) (*Token, error) {
-	bytes, err := ioutil.ReadFile(tokenFile)
+	bytes, err := os.ReadFile(tokenFile)
 	if err != nil {
 		return nil, err
 	}

lsat/store_test.go

@@ -1,7 +1,6 @@
 package lsat
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
@@ -13,7 +12,7 @@ import (
 func TestFileStore(t *testing.T) {
 	t.Parallel()
 
-	tempDirName, err := ioutil.TempDir("", "lsatstore")
+	tempDirName, err := os.MkdirTemp("", "lsatstore")
 	if err != nil {
 		t.Fatal(err)
 	}

proxy/proxy.go

@@ -4,9 +4,9 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"fmt"
-	"io/ioutil"
 	"net/http"
 	"net/http/httputil"
+	"os"
 	"regexp"
 	"strconv"
 	"strings"
@@ -329,7 +329,7 @@ func certPool(services []*Service) (*x509.CertPool, error) {
 			continue
 		}
 
-		b, err := ioutil.ReadFile(service.TLSCertPath)
+		b, err := os.ReadFile(service.TLSCertPath)
 		if err != nil {
 			return nil, err
 		}

proxy/proxy_test.go

@@ -6,9 +6,9 @@ import (
 	"crypto/x509"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
+	"os"
 	"path"
 	"strings"
 	"testing"
@@ -169,7 +169,7 @@ func runHTTPTest(t *testing.T, tc *testCase) {
 
 		// Ensure that we got the response body we expect.
 		defer closeOrFail(t, resp.Body)
-		bodyBytes, err := ioutil.ReadAll(resp.Body)
+		bodyBytes, err := io.ReadAll(resp.Body)
 		require.NoError(t, err)
 
 		require.Equal(t, testHTTPResponseBody, string(bodyBytes))
@@ -188,7 +188,7 @@ func runHTTPTest(t *testing.T, tc *testCase) {
 
 	// Ensure that we got the response body we expect.
 	defer closeOrFail(t, resp.Body)
-	bodyBytes, err := ioutil.ReadAll(resp.Body)
+	bodyBytes, err := io.ReadAll(resp.Body)
 	require.NoError(t, err)
 
 	require.Equal(t, testHTTPResponseBody, string(bodyBytes))
@@ -237,7 +237,7 @@ func TestProxyGRPC(t *testing.T) {
 func runGRPCTest(t *testing.T, tc *testCase) {
 	// Since gRPC only really works over TLS, we need to generate a
 	// certificate and key pair first.
-	tempDirName, err := ioutil.TempDir("", "proxytest")
+	tempDirName, err := os.MkdirTemp("", "proxytest")
 	require.NoError(t, err)
 	certFile := path.Join(tempDirName, "proxy.cert")
 	keyFile := path.Join(tempDirName, "proxy.key")

proxy/service.go

@@ -4,8 +4,8 @@ import (
 	"encoding/base64"
 	"encoding/hex"
 	"fmt"
-	"io/ioutil"
 	"net/http"
+	"os"
 	"regexp"
 	"strings"
 
@@ -154,7 +154,7 @@ func prepareServices(services []*Service) error {
 					"must be '!file+hex:path'")
 			}
 			prefix, fileName := parts[0], parts[1]
-			bytes, err := ioutil.ReadFile(fileName)
+			bytes, err := os.ReadFile(fileName)
 			if err != nil {
 				return err
 			}

secrets_test.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"context"
 	"crypto/sha256"
-	"io/ioutil"
 	"net/url"
 	"os"
 	"testing"
@@ -22,7 +21,7 @@ import (
 func etcdSetup(t *testing.T) (*clientv3.Client, func()) {
 	t.Helper()
 
-	tempDir, err := ioutil.TempDir("", "etcd")
+	tempDir, err := os.MkdirTemp("", "etcd")
 	if err != nil {
 		t.Fatalf("unable to create temp dir: %v", err)
 	}