cmd/swarm: add config file (#15548)

This commit adds a TOML configuration option to swarm. It reuses
the TOML configuration structure used in geth with swarm
customized items.

The commit:

* Adds a "dumpconfig" command to the swarm executable which
  allows printing the (default) configuration to stdout, which
  then can be redirected to a file in order to customize it.
* Adds a "--config <file>" option to the swarm executable which will
  allow to load a configuration file in TOML format from the
  specified location in order to initialize the Swarm node The
  override priorities are like follows: environment variables
  override command line arguments override config file override
  default config.

1 files changed, 321 insertions, 0 deletions

diff --git a/cmd/swarm/config.go b/cmd/swarm/config.go
new file mode 100644
index 000000000..ec81bc741
--- /dev/null
+++ b/cmd/swarm/config.go
@@ -0,0 +1,321 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of go-ethereum.
+//
+// go-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// go-ethereum is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
+
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"reflect"
+	"strconv"
+	"unicode"
+
+	cli "gopkg.in/urfave/cli.v1"
+
+	"github.com/ethereum/go-ethereum/cmd/utils"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/node"
+	"github.com/naoina/toml"
+
+	bzzapi "github.com/ethereum/go-ethereum/swarm/api"
+)
+
+var (
+	//flag definition for the dumpconfig command
+	DumpConfigCommand = cli.Command{
+		Action:      utils.MigrateFlags(dumpConfig),
+		Name:        "dumpconfig",
+		Usage:       "Show configuration values",
+		ArgsUsage:   "",
+		Flags:       app.Flags,
+		Category:    "MISCELLANEOUS COMMANDS",
+		Description: `The dumpconfig command shows configuration values.`,
+	}
+
+	//flag definition for the config file command
+	SwarmTomlConfigPathFlag = cli.StringFlag{
+		Name:  "config",
+		Usage: "TOML configuration file",
+	}
+)
+
+//constants for environment variables
+const (
+	SWARM_ENV_CHEQUEBOOK_ADDR = "SWARM_CHEQUEBOOK_ADDR"
+	SWARM_ENV_ACCOUNT         = "SWARM_ACCOUNT"
+	SWARM_ENV_LISTEN_ADDR     = "SWARM_LISTEN_ADDR"
+	SWARM_ENV_PORT            = "SWARM_PORT"
+	SWARM_ENV_NETWORK_ID      = "SWARM_NETWORK_ID"
+	SWARM_ENV_SWAP_ENABLE     = "SWARM_SWAP_ENABLE"
+	SWARM_ENV_SWAP_API        = "SWARM_SWAP_API"
+	SWARM_ENV_SYNC_ENABLE     = "SWARM_SYNC_ENABLE"
+	SWARM_ENV_ENS_API         = "SWARM_ENS_API"
+	SWARM_ENV_ENS_ADDR        = "SWARM_ENS_ADDR"
+	SWARM_ENV_CORS            = "SWARM_CORS"
+	SWARM_ENV_BOOTNODES       = "SWARM_BOOTNODES"
+	GETH_ENV_DATADIR          = "GETH_DATADIR"
+)
+
+// These settings ensure that TOML keys use the same names as Go struct fields.
+var tomlSettings = toml.Config{
+	NormFieldName: func(rt reflect.Type, key string) string {
+		return key
+	},
+	FieldToKey: func(rt reflect.Type, field string) string {
+		return field
+	},
+	MissingField: func(rt reflect.Type, field string) error {
+		link := ""
+		if unicode.IsUpper(rune(rt.Name()[0])) && rt.PkgPath() != "main" {
+			link = fmt.Sprintf(", check github.com/ethereum/go-ethereum/swarm/api/config.go for available fields")
+		}
+		return fmt.Errorf("field '%s' is not defined in %s%s", field, rt.String(), link)
+	},
+}
+
+//before booting the swarm node, build the configuration
+func buildConfig(ctx *cli.Context) (config *bzzapi.Config, err error) {
+	//check for deprecated flags
+	checkDeprecated(ctx)
+	//start by creating a default config
+	config = bzzapi.NewDefaultConfig()
+	//first load settings from config file (if provided)
+	config, err = configFileOverride(config, ctx)
+	//override settings provided by environment variables
+	config = envVarsOverride(config)
+	//override settings provided by command line
+	config = cmdLineOverride(config, ctx)
+
+	return
+}
+
+//finally, after the configuration build phase is finished, initialize
+func initSwarmNode(config *bzzapi.Config, stack *node.Node, ctx *cli.Context) {
+	//at this point, all vars should be set in the Config
+	//get the account for the provided swarm account
+	prvkey := getAccount(config.BzzAccount, ctx, stack)
+	//set the resolved config path (geth --datadir)
+	config.Path = stack.InstanceDir()
+	//finally, initialize the configuration
+	config.Init(prvkey)
+	//configuration phase completed here
+	log.Debug("Starting Swarm with the following parameters:")
+	//after having created the config, print it to screen
+	log.Debug(printConfig(config))
+}
+
+//override the current config with whatever is in the config file, if a config file has been provided
+func configFileOverride(config *bzzapi.Config, ctx *cli.Context) (*bzzapi.Config, error) {
+	var err error
+
+	//only do something if the -config flag has been set
+	if ctx.GlobalIsSet(SwarmTomlConfigPathFlag.Name) {
+		var filepath string
+		if filepath = ctx.GlobalString(SwarmTomlConfigPathFlag.Name); filepath == "" {
+			utils.Fatalf("Config file flag provided with invalid file path")
+		}
+		f, err := os.Open(filepath)
+		if err != nil {
+			return nil, err
+		}
+		defer f.Close()
+
+		//decode the TOML file into a Config struct
+		//note that we are decoding into the existing defaultConfig;
+		//if an entry is not present in the file, the default entry is kept
+		err = tomlSettings.NewDecoder(f).Decode(&config)
+		// Add file name to errors that have a line number.
+		if _, ok := err.(*toml.LineError); ok {
+			err = errors.New(filepath + ", " + err.Error())
+		}
+	}
+	return config, err
+}
+
+//override the current config with whatever is provided through the command line
+//most values are not allowed a zero value (empty string), if not otherwise noted
+func cmdLineOverride(currentConfig *bzzapi.Config, ctx *cli.Context) *bzzapi.Config {
+
+	if keyid := ctx.GlobalString(SwarmAccountFlag.Name); keyid != "" {
+		currentConfig.BzzAccount = keyid
+	}
+
+	if chbookaddr := ctx.GlobalString(ChequebookAddrFlag.Name); chbookaddr != "" {
+		currentConfig.Contract = common.HexToAddress(chbookaddr)
+	}
+
+	if networkid := ctx.GlobalString(SwarmNetworkIdFlag.Name); networkid != "" {
+		if id, _ := strconv.Atoi(networkid); id != 0 {
+			currentConfig.NetworkId = uint64(id)
+		}
+	}
+
+	if ctx.GlobalIsSet(utils.DataDirFlag.Name) {
+		if datadir := ctx.GlobalString(utils.DataDirFlag.Name); datadir != "" {
+			currentConfig.Path = datadir
+		}
+	}
+
+	bzzport := ctx.GlobalString(SwarmPortFlag.Name)
+	if len(bzzport) > 0 {
+		currentConfig.Port = bzzport
+	}
+
+	if bzzaddr := ctx.GlobalString(SwarmListenAddrFlag.Name); bzzaddr != "" {
+		currentConfig.ListenAddr = bzzaddr
+	}
+
+	if ctx.GlobalIsSet(SwarmSwapEnabledFlag.Name) {
+		currentConfig.SwapEnabled = true
+	}
+
+	if ctx.GlobalIsSet(SwarmSyncEnabledFlag.Name) {
+		currentConfig.SyncEnabled = true
+	}
+
+	currentConfig.SwapApi = ctx.GlobalString(SwarmSwapAPIFlag.Name)
+	if currentConfig.SwapEnabled && currentConfig.SwapApi == "" {
+		utils.Fatalf(SWARM_ERR_SWAP_SET_NO_API)
+	}
+
+	//EnsApi can be set to "", so can't check for empty string, as it is allowed!
+	if ctx.GlobalIsSet(EnsAPIFlag.Name) {
+		currentConfig.EnsApi = ctx.GlobalString(EnsAPIFlag.Name)
+	}
+
+	if ensaddr := ctx.GlobalString(EnsAddrFlag.Name); ensaddr != "" {
+		currentConfig.EnsRoot = common.HexToAddress(ensaddr)
+	}
+
+	if cors := ctx.GlobalString(CorsStringFlag.Name); cors != "" {
+		currentConfig.Cors = cors
+	}
+
+	if ctx.GlobalIsSet(utils.BootnodesFlag.Name) {
+		currentConfig.BootNodes = ctx.GlobalString(utils.BootnodesFlag.Name)
+	}
+
+	return currentConfig
+
+}
+
+//override the current config with whatver is provided in environment variables
+//most values are not allowed a zero value (empty string), if not otherwise noted
+func envVarsOverride(currentConfig *bzzapi.Config) (config *bzzapi.Config) {
+
+	if keyid := os.Getenv(SWARM_ENV_ACCOUNT); keyid != "" {
+		currentConfig.BzzAccount = keyid
+	}
+
+	if chbookaddr := os.Getenv(SWARM_ENV_CHEQUEBOOK_ADDR); chbookaddr != "" {
+		currentConfig.Contract = common.HexToAddress(chbookaddr)
+	}
+
+	if networkid := os.Getenv(SWARM_ENV_NETWORK_ID); networkid != "" {
+		if id, _ := strconv.Atoi(networkid); id != 0 {
+			currentConfig.NetworkId = uint64(id)
+		}
+	}
+
+	if datadir := os.Getenv(GETH_ENV_DATADIR); datadir != "" {
+		currentConfig.Path = datadir
+	}
+
+	bzzport := os.Getenv(SWARM_ENV_PORT)
+	if len(bzzport) > 0 {
+		currentConfig.Port = bzzport
+	}
+
+	if bzzaddr := os.Getenv(SWARM_ENV_LISTEN_ADDR); bzzaddr != "" {
+		currentConfig.ListenAddr = bzzaddr
+	}
+
+	if swapenable := os.Getenv(SWARM_ENV_SWAP_ENABLE); swapenable != "" {
+		if swap, err := strconv.ParseBool(swapenable); err != nil {
+			currentConfig.SwapEnabled = swap
+		}
+	}
+
+	if syncenable := os.Getenv(SWARM_ENV_SYNC_ENABLE); syncenable != "" {
+		if sync, err := strconv.ParseBool(syncenable); err != nil {
+			currentConfig.SyncEnabled = sync
+		}
+	}
+
+	if swapapi := os.Getenv(SWARM_ENV_SWAP_API); swapapi != "" {
+		currentConfig.SwapApi = swapapi
+	}
+
+	if currentConfig.SwapEnabled && currentConfig.SwapApi == "" {
+		utils.Fatalf(SWARM_ERR_SWAP_SET_NO_API)
+	}
+
+	//EnsApi can be set to "", so can't check for empty string, as it is allowed
+	if ensapi, exists := os.LookupEnv(SWARM_ENV_ENS_API); exists == true {
+		currentConfig.EnsApi = ensapi
+	}
+
+	if ensaddr := os.Getenv(SWARM_ENV_ENS_ADDR); ensaddr != "" {
+		currentConfig.EnsRoot = common.HexToAddress(ensaddr)
+	}
+
+	if cors := os.Getenv(SWARM_ENV_CORS); cors != "" {
+		currentConfig.Cors = cors
+	}
+
+	if bootnodes := os.Getenv(SWARM_ENV_BOOTNODES); bootnodes != "" {
+		currentConfig.BootNodes = bootnodes
+	}
+
+	return currentConfig
+}
+
+// dumpConfig is the dumpconfig command.
+// writes a default config to STDOUT
+func dumpConfig(ctx *cli.Context) error {
+	cfg, err := buildConfig(ctx)
+	if err != nil {
+		utils.Fatalf(fmt.Sprintf("Uh oh - dumpconfig triggered an error %v", err))
+	}
+	comment := ""
+	out, err := tomlSettings.Marshal(&cfg)
+	if err != nil {
+		return err
+	}
+	io.WriteString(os.Stdout, comment)
+	os.Stdout.Write(out)
+	return nil
+}
+
+//deprecated flags checked here
+func checkDeprecated(ctx *cli.Context) {
+	// exit if the deprecated --ethapi flag is set
+	if ctx.GlobalString(DeprecatedEthAPIFlag.Name) != "" {
+		utils.Fatalf("--ethapi is no longer a valid command line flag, please use --ens-api and/or --swap-api.")
+	}
+}
+
+//print a Config as string
+func printConfig(config *bzzapi.Config) string {
+	out, err := tomlSettings.Marshal(&config)
+	if err != nil {
+		return (fmt.Sprintf("Something is not right with the configuration: %v", err))
+	}
+	return string(out)
+}