Avoid unknown fields on config

This will reduce headaches when adding the wrong fields to the config.

Signed-off-by: Antonio Navarro Perez <[email protected]>

Author: ajnavarro

cmd/ipfs/daemon.go

@@ -19,7 +19,6 @@ import (
 	utilmain "github.com/ipfs/kubo/cmd/ipfs/util"
 	oldcmds "github.com/ipfs/kubo/commands"
 	config "github.com/ipfs/kubo/config"
-	cserial "github.com/ipfs/kubo/config/serialize"
 	"github.com/ipfs/kubo/core"
 	commands "github.com/ipfs/kubo/core/commands"
 	"github.com/ipfs/kubo/core/coreapi"
@@ -252,7 +251,7 @@ func daemonFunc(req *cmds.Request, re cmds.ResponseEmitter, env cmds.Environment
 		var conf *config.Config
 
 		if cfgLocation != "" {
-			if conf, err = cserial.Load(cfgLocation); err != nil {
+			if conf, err = config.Load(cfgLocation); err != nil {
 				return err
 			}
 		}

config/config.go

@@ -4,14 +4,21 @@ package config
 import (
 	"bytes"
 	"encoding/json"
+	"errors"
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"strings"
 
+	"github.com/facebookgo/atomicfile"
 	"github.com/mitchellh/go-homedir"
 )
 
+// ErrNotInitialized is returned when we fail to read the config because the
+// repo doesn't exist.
+var ErrNotInitialized = errors.New("ipfs not initialized, please run 'ipfs init'")
+
 // Config is used to load ipfs config files.
 type Config struct {
 	Identity  Identity  // local node's peer identity
@@ -101,35 +108,36 @@ func HumanOutput(value interface{}) ([]byte, error) {
 	if ok {
 		return []byte(strings.Trim(s, "\n")), nil
 	}
-	return Marshal(value)
-}
 
-// Marshal configuration with JSON
-func Marshal(value interface{}) ([]byte, error) {
-	// need to prettyprint, hence MarshalIndent, instead of Encoder
-	return json.MarshalIndent(value, "", "  ")
+	buf := new(bytes.Buffer)
+	if err := encodeConfigFile(buf, value); err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
 }
 
 func FromMap(v map[string]interface{}) (*Config, error) {
 	buf := new(bytes.Buffer)
-	if err := json.NewEncoder(buf).Encode(v); err != nil {
+
+	if err := encodeConfigFile(buf, v); err != nil {
 		return nil, err
 	}
 	var conf Config
-	if err := json.NewDecoder(buf).Decode(&conf); err != nil {
-		return nil, fmt.Errorf("failure to decode config: %s", err)
+	if err := decodeConfigFile(buf, &conf); err != nil {
+		return nil, err
 	}
 	return &conf, nil
 }
 
 func ToMap(conf *Config) (map[string]interface{}, error) {
 	buf := new(bytes.Buffer)
-	if err := json.NewEncoder(buf).Encode(conf); err != nil {
+	if err := encodeConfigFile(buf, conf); err != nil {
 		return nil, err
 	}
 	var m map[string]interface{}
-	if err := json.NewDecoder(buf).Decode(&m); err != nil {
-		return nil, fmt.Errorf("failure to decode config: %s", err)
+	if err := decodeConfigFile(buf, &m); err != nil {
+		return nil, err
 	}
 	return m, nil
 }
@@ -139,13 +147,74 @@ func (c *Config) Clone() (*Config, error) {
 	var newConfig Config
 	var buf bytes.Buffer
 
-	if err := json.NewEncoder(&buf).Encode(c); err != nil {
-		return nil, fmt.Errorf("failure to encode config: %s", err)
+	if err := encodeConfigFile(&buf, c); err != nil {
+		return nil, err
 	}
-
-	if err := json.NewDecoder(&buf).Decode(&newConfig); err != nil {
-		return nil, fmt.Errorf("failure to decode config: %s", err)
+	if err := decodeConfigFile(&buf, &newConfig); err != nil {
+		return nil, err
 	}
 
 	return &newConfig, nil
 }
+
+// ReadConfigFile reads the config from `filename` into `cfg`.
+func ReadConfigFile(filename string, cfg interface{}) error {
+	f, err := os.Open(filename)
+	if err != nil {
+		if os.IsNotExist(err) {
+			err = ErrNotInitialized
+		}
+		return err
+	}
+	defer f.Close()
+
+	return decodeConfigFile(f, cfg)
+}
+
+func decodeConfigFile(r io.Reader, cfg interface{}) error {
+	dec := json.NewDecoder(r)
+	if os.Getenv("IPFS_CONFIG_TOLERANT_MODE") == "" {
+		dec.DisallowUnknownFields()
+	}
+
+	if err := dec.Decode(cfg); err != nil {
+		return fmt.Errorf("failure to decode config: %s", err)
+	}
+
+	return nil
+}
+
+// WriteConfigFile writes the config from `cfg` into `filename`.
+func WriteConfigFile(filename string, cfg interface{}) error {
+	err := os.MkdirAll(filepath.Dir(filename), 0755)
+	if err != nil {
+		return err
+	}
+
+	f, err := atomicfile.New(filename, 0600)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	return encodeConfigFile(f, cfg)
+}
+
+// encodeConfigFile encodes configuration with JSON
+func encodeConfigFile(w io.Writer, value interface{}) error {
+	enc := json.NewEncoder(w)
+	enc.SetIndent("", "    ")
+
+	return enc.Encode(value)
+}
+
+// Load reads given file and returns the read config, or error.
+func Load(filename string) (*Config, error) {
+	var cfg Config
+	err := ReadConfigFile(filename, &cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	return &cfg, err
+}

config/config_test.go

@@ -1,6 +1,8 @@
 package config
 
 import (
+	"os"
+	"runtime"
 	"testing"
 )
 
@@ -27,3 +29,64 @@ func TestClone(t *testing.T) {
 		t.Fatal("HTTP headers not preserved")
 	}
 }
+
+func TestConfig(t *testing.T) {
+	const filename = ".ipfsconfig"
+	cfgWritten := new(Config)
+	cfgWritten.Identity.PeerID = "faketest"
+
+	err := WriteConfigFile(filename, cfgWritten)
+	if err != nil {
+		t.Fatal(err)
+	}
+	cfgRead, err := Load(filename)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cfgWritten.Identity.PeerID != cfgRead.Identity.PeerID {
+		t.Fatal()
+	}
+	st, err := os.Stat(filename)
+	if err != nil {
+		t.Fatalf("cannot stat config file: %v", err)
+	}
+
+	if runtime.GOOS != "windows" { // see https://golang.org/src/os/types_windows.go
+		if g := st.Mode().Perm(); g&0117 != 0 {
+			t.Fatalf("config file should not be executable or accessible to world: %v", g)
+		}
+	}
+}
+
+func TestConfigUnknownField(t *testing.T) {
+	const filename = ".ipfsconfig"
+
+	badConfig := map[string]string{
+		"BadField": "Value",
+	}
+
+	err := WriteConfigFile(filename, badConfig)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = Load(filename)
+	if err == nil {
+		t.Fatal("load must fail")
+	}
+
+	if err.Error() != "failure to decode config: json: unknown field \"BadField\"" {
+		t.Fatal("unexpected error:", err)
+	}
+
+	mapOut := make(map[string]string)
+
+	err = ReadConfigFile(filename, &mapOut)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if mapOut["BadField"] != "Value" {
+		t.Fatal(err)
+	}
+}

config/serialize/serialize.go

@@ -114,6 +114,13 @@ $ ipfs resolve -r /ipns/dnslink-test2.example.com
 /ipfs/bafkreicysg23kiwv34eg2d7qweipxwosdo2py4ldv42nbauguluen5v6am
 ```
 
+## `IPFS_CONFIG_TOLERANT_MODE`
+
+Disables strict config valiadtion to allow unsupported fields on JSON config.
+
+Default: false
+
+
 ## `LIBP2P_TCP_REUSEPORT`
 
 Kubo tries to reuse the same source port for all connections to improve NAT

config/serialize/serialize_test.go

@@ -9,7 +9,6 @@ import (
 	"strings"
 
 	config "github.com/ipfs/kubo/config"
-	cserialize "github.com/ipfs/kubo/config/serialize"
 	"github.com/ipld/go-ipld-prime/multicodec"
 
 	"github.com/ipfs/kubo/core"
@@ -97,9 +96,9 @@ type PluginLoader struct {
 func NewPluginLoader(repo string) (*PluginLoader, error) {
 	loader := &PluginLoader{plugins: make(map[string]plugin.Plugin, len(preloadPlugins)), repo: repo}
 	if repo != "" {
-		cfg, err := cserialize.Load(filepath.Join(repo, config.DefaultConfigFile))
+		cfg, err := config.Load(filepath.Join(repo, config.DefaultConfigFile))
 		switch err {
-		case cserialize.ErrNotInitialized:
+		case config.ErrNotInitialized:
 		case nil:
 			loader.config = cfg.Plugins
 		default: