feat: improve error handling.

- skip EOF error

cmd/kv.go

@@ -92,7 +92,7 @@ func createTLSConfig(cmd *cobra.Command) (*tls.Config, error) {
 
 	cert, err := getCertificate(privateKey, certContent)
 	if err != nil {
-		return nil, fmt.Errorf("failed to load TLS keypair: %s", err)
+		return nil, fmt.Errorf("failed to load TLS keypair: %w", err)
 	}
 
 	return &tls.Config{
@@ -109,7 +109,7 @@ func getCertPool(ca string) (*x509.CertPool, error) {
 	if ca != "" {
 		caContent, err := getCAContent(ca)
 		if err != nil {
-			return nil, fmt.Errorf("failed to read CA. %s", err)
+			return nil, fmt.Errorf("failed to read CA. %w", err)
 		}
 
 		if !caPool.AppendCertsFromPEM(caContent) {

cmd/root.go

@@ -109,7 +109,7 @@ func runE(apply func(*dumper.BaseConfig, *cobra.Command) error) func(*cobra.Comm
 func tree(root, indent string) error {
 	fi, err := os.Stat(root)
 	if err != nil {
-		return fmt.Errorf("could not stat %s: %v", root, err)
+		return fmt.Errorf("could not stat %s: %w", root, err)
 	}
 
 	fmt.Println(fi.Name())
@@ -119,7 +119,7 @@ func tree(root, indent string) error {
 
 	fis, err := ioutil.ReadDir(root)
 	if err != nil {
-		return fmt.Errorf("could not read dir %s: %v", root, err)
+		return fmt.Errorf("could not read dir %s: %w", root, err)
 	}
 
 	var names []string

dumper/file/file.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"crypto/md5"
 	"encoding/json"
+	"errors"
+	"fmt"
 	"io"
 	"log"
 	"os"
@@ -34,20 +36,24 @@ func Dump(acmeFile string, baseConfig *dumper.BaseConfig) error {
 
 func dump(acmeFile string, baseConfig *dumper.BaseConfig) error {
 	if baseConfig.Version == "v2" {
-		return dumpV2(acmeFile, baseConfig)
+		err := dumpV2(acmeFile, baseConfig)
+		if err != nil {
+			return fmt.Errorf("v2: dump failed: %w", err)
+		}
+		return nil
 	}
 
-	return dumpV1(acmeFile, baseConfig)
+	err := dumpV1(acmeFile, baseConfig)
+	if err != nil {
+		return fmt.Errorf("v1: dump failed: %w", err)
+	}
+	return nil
 }
 
 func dumpV1(acmeFile string, baseConfig *dumper.BaseConfig) error {
-	source, err := os.Open(acmeFile)
-	if err != nil {
-		return err
-	}
-
 	data := &v1.StoredData{}
-	if err = json.NewDecoder(source).Decode(data); err != nil {
+	err := readJSONFile(acmeFile, data)
+	if err != nil {
 		return err
 	}
 
@@ -55,23 +61,38 @@ func dumpV1(acmeFile string, baseConfig *dumper.BaseConfig) error {
 }
 
 func dumpV2(acmeFile string, baseConfig *dumper.BaseConfig) error {
-	source, err := os.Open(acmeFile)
-	if err != nil {
-		return err
-	}
-
 	data := map[string]*acme.StoredData{}
-	if err = json.NewDecoder(source).Decode(&data); err != nil {
+	err := readJSONFile(acmeFile, &data)
+	if err != nil {
 		return err
 	}
 
 	return v2.Dump(data, baseConfig)
 }
 
+func readJSONFile(acmeFile string, data interface{}) error {
+	source, err := os.Open(acmeFile)
+	if err != nil {
+		return fmt.Errorf("failed to open file %q: %w", acmeFile, err)
+	}
+	defer func() { _ = source.Close() }()
+
+	err = json.NewDecoder(source).Decode(data)
+	if errors.Is(err, io.EOF) {
+		log.Printf("warn: file %q may not be ready: %v", acmeFile, err)
+		return nil
+	}
+	if err != nil {
+		return fmt.Errorf("failed to unmarshal file %q: %w", acmeFile, err)
+	}
+
+	return nil
+}
+
 func watch(acmeFile string, baseConfig *dumper.BaseConfig) error {
 	watcher, err := fsnotify.NewWatcher()
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to create new watcher: %w", err)
 	}
 
 	defer func() { _ = watcher.Close() }()
@@ -114,7 +135,7 @@ func watch(acmeFile string, baseConfig *dumper.BaseConfig) error {
 
 	err = watcher.Add(acmeFile)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to add a new watcher: %w", err)
 	}
 
 	<-done
@@ -125,12 +146,12 @@ func watch(acmeFile string, baseConfig *dumper.BaseConfig) error {
 func manageEvent(watcher *fsnotify.Watcher, event fsnotify.Event, acmeFile string, previousHash []byte, baseConfig *dumper.BaseConfig) ([]byte, error) {
 	err := manageRename(watcher, event, acmeFile)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("watcher renewal failed: %w", err)
 	}
 
 	hash, err := calculateHash(acmeFile)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("file hash calculation failed: %w", err)
 	}
 
 	if !bytes.Equal(previousHash, hash) {

dumper/kv/convert.go

@@ -45,13 +45,15 @@ type DomainsCertificate struct {
 
 // convertOldAccount converts account information from old account format.
 func convertOldAccount(account *AccountOld) *v1.StoredData {
-	storedData := &v1.StoredData{}
+	storedData := &v1.StoredData{
-	storedData.Account = &v1.Account{
+		Account: &v1.Account{
-		PrivateKey:   account.PrivateKey,
+			PrivateKey:   account.PrivateKey,
-		Registration: account.Registration,
+			Registration: account.Registration,
-		Email:        account.Email,
+			Email:        account.Email,
-		KeyType:      account.KeyType,
+			KeyType:      account.KeyType,
+		},
 	}
+
 	var certs []*v1.Certificate
 	for _, oldCert := range account.DomainsCertificate.Certs {
 		certs = append(certs, &v1.Certificate{
@@ -61,5 +63,6 @@ func convertOldAccount(account *AccountOld) *v1.StoredData {
 		})
 	}
 	storedData.Certificates = certs
+
 	return storedData
 }

dumper/kv/kv.go

@@ -24,7 +24,7 @@ const DefaultStoreKeySuffix = "/acme/account/object"
 func Dump(config *Config, baseConfig *dumper.BaseConfig) error {
 	kvStore, err := valkeyrie.NewStore(config.Backend, config.Endpoints, config.Options)
 	if err != nil {
-		return fmt.Errorf("unable to create client of the store: %v", err)
+		return fmt.Errorf("unable to create client of the store: %w", err)
 	}
 
 	storeKey := config.Prefix + config.Suffix
@@ -35,7 +35,7 @@ func Dump(config *Config, baseConfig *dumper.BaseConfig) error {
 
 	pair, err := kvStore.Get(storeKey, nil)
 	if err != nil {
-		return fmt.Errorf("unable to retrieve %s value: %v", storeKey, err)
+		return fmt.Errorf("unable to retrieve %s value: %w", storeKey, err)
 	}
 
 	return dumpPair(pair, baseConfig)
@@ -80,17 +80,17 @@ func dumpPair(pair *store.KVPair, baseConfig *dumper.BaseConfig) error {
 func getStoredDataFromGzip(pair *store.KVPair) (*v1.StoredData, error) {
 	reader, err := gzip.NewReader(bytes.NewBuffer(pair.Value))
 	if err != nil {
-		return nil, fmt.Errorf("fail to create GZip reader: %v", err)
+		return nil, fmt.Errorf("fail to create GZip reader: %w", err)
 	}
 
 	acmeData, err := ioutil.ReadAll(reader)
 	if err != nil {
-		return nil, fmt.Errorf("unable to read the pair content: %v", err)
+		return nil, fmt.Errorf("unable to read the pair content: %w", err)
 	}
 
 	account := &AccountOld{}
 	if err := json.Unmarshal(acmeData, &account); err != nil {
-		return nil, fmt.Errorf("unable marshal AccountOld: %v", err)
+		return nil, fmt.Errorf("unable marshal AccountOld: %w", err)
 	}
 
 	return convertOldAccount(account), nil

dumper/v1/dumper.go

@@ -2,6 +2,7 @@ package v1
 
 import (
 	"encoding/pem"
+	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -20,29 +21,29 @@ func Dump(data *StoredData, baseConfig *dumper.BaseConfig) error {
 	if baseConfig.Clean {
 		err := cleanDir(baseConfig.DumpPath)
 		if err != nil {
-			return err
+			return fmt.Errorf("folder cleaning failed: %w", err)
 		}
 	}
 
 	if !baseConfig.DomainSubDir {
 		if err := os.MkdirAll(filepath.Join(baseConfig.DumpPath, certsSubDir), 0755); err != nil {
-			return err
+			return fmt.Errorf("certs folder creation failure: %w", err)
 		}
 	}
 
 	if err := os.MkdirAll(filepath.Join(baseConfig.DumpPath, keysSubDir), 0755); err != nil {
-		return err
+		return fmt.Errorf("keys folder creation failure: %w", err)
 	}
 
 	for _, cert := range data.Certificates {
 		err := writeCert(baseConfig.DumpPath, cert, baseConfig.CrtInfo, baseConfig.DomainSubDir)
 		if err != nil {
-			return err
+			return fmt.Errorf("failed to write certificates: %w", err)
 		}
 
 		err = writeKey(baseConfig.DumpPath, cert, baseConfig.KeyInfo, baseConfig.DomainSubDir)
 		if err != nil {
-			return err
+			return fmt.Errorf("failed to write certificate keys: %w", err)
 		}
 	}
 

dumper/v2/dumper.go

@@ -2,6 +2,7 @@ package v2
 
 import (
 	"encoding/pem"
+	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -21,30 +22,30 @@ func Dump(data map[string]*acme.StoredData, baseConfig *dumper.BaseConfig) error
 	if baseConfig.Clean {
 		err := cleanDir(baseConfig.DumpPath)
 		if err != nil {
-			return err
+			return fmt.Errorf("folder cleaning failed: %w", err)
 		}
 	}
 
 	if !baseConfig.DomainSubDir {
 		if err := os.MkdirAll(filepath.Join(baseConfig.DumpPath, certsSubDir), 0755); err != nil {
-			return err
+			return fmt.Errorf("certs folder creation failure: %w", err)
 		}
 	}
 
 	if err := os.MkdirAll(filepath.Join(baseConfig.DumpPath, keysSubDir), 0755); err != nil {
-		return err
+		return fmt.Errorf("keys folder creation failure: %w", err)
 	}
 
 	for _, store := range data {
 		for _, cert := range store.Certificates {
 			err := writeCert(baseConfig.DumpPath, cert.Certificate, baseConfig.CrtInfo, baseConfig.DomainSubDir)
 			if err != nil {
-				return err
+				return fmt.Errorf("failed to write certificates: %w", err)
 			}
 
 			err = writeKey(baseConfig.DumpPath, cert.Certificate, baseConfig.KeyInfo, baseConfig.DomainSubDir)
 			if err != nil {
-				return err
+				return fmt.Errorf("failed to write certificate keys: %w", err)
 			}
 		}
 
@@ -56,7 +57,7 @@ func Dump(data map[string]*acme.StoredData, baseConfig *dumper.BaseConfig) error
 
 		err := ioutil.WriteFile(filepath.Join(baseConfig.DumpPath, keysSubDir, "letsencrypt"+baseConfig.KeyInfo.Ext), privateKeyPem, 0600)
 		if err != nil {
-			return err
+			return fmt.Errorf("failed to write private key: %w", err)
 		}
 	}