cmd/geth: add --config file flag (#13875)

* p2p/discover, p2p/discv5: add marshaling methods to Node

* p2p/netutil: make Netlist decodable from TOML

* common/math: encode nil HexOrDecimal256 as 0x0

* cmd/geth: add --config file flag

* cmd/geth: add missing license header

* eth: prettify Config again, fix tests

* eth: use gasprice.Config instead of duplicating its fields

* eth/gasprice: hide nil default from dumpconfig output

* cmd/geth: hide genesis block in dumpconfig output

* node: make tests compile

* console: fix tests

* cmd/geth: make TOML keys look exactly like Go struct fields

* p2p: use discovery by default

This makes the zero Config slightly more useful. It also fixes package
node tests because Node detects reuse of the datadir through the
NodeDatabase.

* cmd/geth: make ethstats URL settable through config file

* cmd/faucet: fix configuration

* cmd/geth: dedup attach tests

* eth: add comment for DefaultConfig

* eth: pass downloader.SyncMode in Config

This removes the FastSync, LightSync flags in favour of a more
general SyncMode flag.

* cmd/utils: remove jitvm flags

* cmd/utils: make mutually exclusive flag error prettier

It now reads:

   Fatal: flags --dev, --testnet can't be used at the same time

* p2p: fix typo

* node: add DefaultConfig, use it for geth

* mobile: add missing NoDiscovery option

* cmd/utils: drop MakeNode

This exposed a couple of places that needed to be updated to use
node.DefaultConfig.

* node: fix typo

* eth: make fast sync the default mode

* cmd/utils: remove IPCApiFlag (unused)

* node: remove default IPC path

Set it in the frontends instead.

* cmd/geth: add --syncmode

* cmd/utils: make --ipcdisable and --ipcpath mutually exclusive

* cmd/utils: don't enable WS, HTTP when setting addr

* cmd/utils: fix --identity

1 files changed, 33 insertions, 0 deletions

diff --git a/eth/downloader/modes.go b/eth/downloader/modes.go
index ae3c43888..8ecdf91f1 100644
--- a/eth/downloader/modes.go
+++ b/eth/downloader/modes.go
@@ -16,6 +16,8 @@
 
 package downloader
 
+import "fmt"
+
 // SyncMode represents the synchronisation mode of the downloader.
 type SyncMode int
 
@@ -25,6 +27,10 @@ const (
 	LightSync                 // Download only the headers and terminate afterwards
 )
 
+func (mode SyncMode) IsValid() bool {
+	return mode >= FullSync && mode <= LightSync
+}
+
 // String implements the stringer interface.
 func (mode SyncMode) String() string {
 	switch mode {
@@ -38,3 +44,30 @@ func (mode SyncMode) String() string {
 		return "unknown"
 	}
 }
+
+func (mode SyncMode) MarshalText() ([]byte, error) {
+	switch mode {
+	case FullSync:
+		return []byte("full"), nil
+	case FastSync:
+		return []byte("fast"), nil
+	case LightSync:
+		return []byte("light"), nil
+	default:
+		return nil, fmt.Errorf("unknown sync mode %d", mode)
+	}
+}
+
+func (mode *SyncMode) UnmarshalText(text []byte) error {
+	switch string(text) {
+	case "full":
+		*mode = FullSync
+	case "fast":
+		*mode = FastSync
+	case "light":
+		*mode = LightSync
+	default:
+		return fmt.Errorf(`unknown sync mode %q, want "full", "fast" or "light"`, text)
+	}
+	return nil
+}