cmd/utils: implement configurable developer (--dev) account options

[meowsbits]

Prior to this change --dev (developer) mode
generated one account with an empty password,
irrespective of existing --password and --miner.etherbase
options.

This change makes --dev mode compatible with these
existing flags.

--dev mode may now be used in conjunction with
--password and --miner.etherbase flags to configure
the developer faucet using an existing keystore or
in creating a new account.

---

> cat demo-dev-ks.sh 
#!/usr/bin/env bash

set -x

rm -rf ./ks
mkdir ks
echo "mypassphrase" > pass.txt
./build/bin/geth --keystore=./ks --password=./pass.txt account new
./build/bin/geth --keystore=./ks --password=./pass.txt account new
./build/bin/geth --keystore=./ks --password=./pass.txt account new

# Take the _middle_ address, where normally --dev would default to the first (or last?).
addr=$(cat ./ks/* | jq -r '.address' | tail -2 | head -1)
./build/bin/geth --dev --dev.period=1 --keystore=./ks --password=./pass.txt --miner.etherbase="$addr" --exec 'exit' console

> ./demo-dev-ks.sh
+ rm -rf ./ks
+ mkdir ks
+ echo mypassphrase
+ ./build/bin/geth --keystore=./ks --password=./pass.txt account new
INFO [07-07|08:29:44.270] Maximum peer count                       ETH=50 LES=0 total=50
INFO [07-07|08:29:44.270] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"

Your new key was generated

Public address of the key:   0xBADf17be3d483D06B2DcBCA1d60457cD89fd0a1a
Path of the secret key file: /home/ia/go/src/github.com/ethereum/go-ethereum/ks/UTC--2020-07-07T13-29-44.270890139Z--badf17be3d483d06b2dcbca1d60457cd89fd0a1a

- You can share your public address with anyone. Others need it to interact with you.
- You must NEVER share the secret key with anyone! The key controls access to your funds!
- You must BACKUP your key file! Without the key, it's impossible to access account funds!
- You must REMEMBER your password! Without the password, it's impossible to decrypt the key!

+ ./build/bin/geth --keystore=./ks --password=./pass.txt account new
INFO [07-07|08:29:45.595] Maximum peer count                       ETH=50 LES=0 total=50
INFO [07-07|08:29:45.595] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"

Your new key was generated

Public address of the key:   0x5F038071f11ab6566E5994617fB705140e222D6D
Path of the secret key file: /home/ia/go/src/github.com/ethereum/go-ethereum/ks/UTC--2020-07-07T13-29-45.595832831Z--5f038071f11ab6566e5994617fb705140e222d6d

- You can share your public address with anyone. Others need it to interact with you.
- You must NEVER share the secret key with anyone! The key controls access to your funds!
- You must BACKUP your key file! Without the key, it's impossible to access account funds!
- You must REMEMBER your password! Without the password, it's impossible to decrypt the key!

+ ./build/bin/geth --keystore=./ks --password=./pass.txt account new
INFO [07-07|08:29:46.937] Maximum peer count                       ETH=50 LES=0 total=50
INFO [07-07|08:29:46.937] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"

Your new key was generated

Public address of the key:   0x5F5CfB9F81FA7Bcd86147034582d6766072ec96f
Path of the secret key file: /home/ia/go/src/github.com/ethereum/go-ethereum/ks/UTC--2020-07-07T13-29-46.937960824Z--5f5cfb9f81fa7bcd86147034582d6766072ec96f

- You can share your public address with anyone. Others need it to interact with you.
- You must NEVER share the secret key with anyone! The key controls access to your funds!
- You must BACKUP your key file! Without the key, it's impossible to access account funds!
- You must REMEMBER your password! Without the password, it's impossible to decrypt the key!

++ cat ./ks/UTC--2020-07-07T13-29-44.270890139Z--badf17be3d483d06b2dcbca1d60457cd89fd0a1a ./ks/UTC--2020-07-07T13-29-45.595832831Z--5f038071f11ab6566e5994617fb705140e222d6d ./ks/UTC--2020-07-07T13-29-46.937960824Z--5f5cfb9f81fa7bcd86147034582d6766072ec96f
++ jq -r .address
++ tail -2
++ head -1
+ addr=5f038071f11ab6566e5994617fb705140e222d6d
+ ./build/bin/geth --dev --dev.period=1 --keystore=./ks --password=./pass.txt --miner.etherbase=5f038071f11ab6566e5994617fb705140e222d6d --exec exit console
INFO [07-07|08:29:48.268] Starting Geth in ephemeral dev mode... 
INFO [07-07|08:29:48.269] Maximum peer count                       ETH=50 LES=0 total=50
INFO [07-07|08:29:48.269] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"
INFO [07-07|08:29:48.270] Set global gas cap                       cap=25000000
INFO [07-07|08:29:48.899] Using developer account                  address=0x5F038071f11ab6566E5994617fB705140e222D6D
INFO [07-07|08:29:48.899] Starting peer-to-peer node               instance=Geth/v1.9.16-unstable-e5871b92-20200707/linux-amd64/go1.14.3
INFO [07-07|08:29:48.899] Allocated trie memory caches             clean=256.00MiB dirty=256.00MiB
INFO [07-07|08:29:48.899] Writing custom genesis block 
INFO [07-07|08:29:48.900] Persisted trie from memory database      nodes=11 size=1.66KiB time="29.577µs" gcnodes=0 gcsize=0.00B gctime=0s livenodes=1 livesize=0.00B
INFO [07-07|08:29:48.900] Initialised chain configuration          config="{ChainID: 1337 Homestead: 0 DAO: <nil> DAOSupport: false EIP150: 0 EIP155: 0 EIP158: 0 Byzantium: 0 Constantinople: 0 Petersburg: 0 Istanbul: 0, Muir Glacier: <nil>, YOLO v1: <nil>, Engine: clique}"
INFO [07-07|08:29:48.900] Initialising Ethereum protocol           versions="[65 64 63]" network=1337 dbversion=<nil>
WARN [07-07|08:29:48.900] Upgrade blockchain database version      from=<nil> to=7
INFO [07-07|08:29:48.900] Loaded most recent local header          number=0 hash="ba7e2e…b71f7c" td=1 age=51y3mo13h
INFO [07-07|08:29:48.900] Loaded most recent local full block      number=0 hash="ba7e2e…b71f7c" td=1 age=51y3mo13h
INFO [07-07|08:29:48.900] Loaded most recent local fast block      number=0 hash="ba7e2e…b71f7c" td=1 age=51y3mo13h
INFO [07-07|08:29:48.906] Allocated fast sync bloom                size=512.00MiB
INFO [07-07|08:29:48.907] Stored checkpoint snapshot to disk       number=0 hash="ba7e2e…b71f7c"
INFO [07-07|08:29:48.908] started whisper v.6.0 
INFO [07-07|08:29:48.908] New local node record                    seq=1 id=6a823af52791d1b6 ip=127.0.0.1 udp=0 tcp=39337
INFO [07-07|08:29:48.909] Started P2P networking                   self="enode://023fe62cf3531c53ece7f872d841a51784493ca3fc18cdcdf352f684f9743d64746cce02c3c83ecf04fc1fcd2fcd66878f45cc3bb2a98737fb8ca120ca1820c6@127.0.0.1:39337?discport=0"
INFO [07-07|08:29:48.909] IPC endpoint opened                      url=/tmp/geth.ipc
INFO [07-07|08:29:48.910] Transaction pool price threshold updated price=1000000000
INFO [07-07|08:29:48.910] Transaction pool price threshold updated price=1
INFO [07-07|08:29:48.910] Commit new mining work                   number=1 sealhash="f20c05…cdd34e" uncles=0 txs=0 gas=0 fees=0 elapsed="114.39µs"
INFO [07-07|08:29:48.910] Successfully sealed new block            number=1 sealhash="f20c05…cdd34e" hash="aa8ad9…bd9916" elapsed="469.841µs"
INFO [07-07|08:29:48.910] 🔨 mined potential block                  number=1 hash="aa8ad9…bd9916"
INFO [07-07|08:29:48.911] Commit new mining work                   number=2 sealhash="60b74a…2e12d7" uncles=0 txs=0 gas=0 fees=0 elapsed="333.98µs"
INFO [07-07|08:29:48.911] Initialized fast sync bloom              items=11 errorrate=0.000 elapsed=4.559ms
INFO [07-07|08:29:48.916] Mapped network port                      proto=tcp extport=39337 intport=39337 interface=NAT-PMP(192.168.0.1)
ReferenceError: exit is not defined
	at <eval>:1:1(0)

INFO [07-07|08:29:48.940] IPC endpoint closed                      url=/tmp/geth.ipc
INFO [07-07|08:29:48.940] Ethereum protocol stopped 
INFO [07-07|08:29:48.940] Transaction pool stopped 
INFO [07-07|08:29:48.940] Writing cached state to disk             block=1 hash="aa8ad9…bd9916" root="c5e561…807777"
INFO [07-07|08:29:48.940] Persisted trie from memory database      nodes=0  size=0.00B     time="2.647µs"  gcnodes=0 gcsize=0.00B gctime=0s livenodes=1 livesize=0.00B
INFO [07-07|08:29:48.940] Blockchain stopped 
INFO [07-07|08:29:48.940] whisper stopped 

[holiman]

I don't know if we should make --dev mode more advanced, and integrate it with actual keystores. In my opinion, it's for dev testing, and in scenarios where something more advanced is required, it's better to set it up properly with an actual chain config.

This PR makes it possible for someone to point the devmode to use/interact with the actual mainnet keystore.

[meowsbits]

Dev mode already can interact with the actual mainnet keystore as well as any other keystore.

> mv ~/.ethereum/keystore{,.bak}
> mkdir ~/.ethereum/keystore
> ./build/bin/geth --dev --keystore=~/.ethereum/keystore --exec 'exit;' console > /dev/null 2>&1
> ls -lshat ~/.ethereum/keystore
-rw------- 1 ia ia 491 Jul  7 20:05 UTC--2020-07-08T01-05-08.752300796Z--236cfc1e5ebab5d73a7ff819ca4880d2d16043ab
> ./build/bin/geth version
Geth
Version: 1.9.16-unstable
Git Commit: e5871b928fb0a4caf65153b552187c5c103e24d7
Architecture: amd64
Protocol Versions: [65 64 63]
Go Version: go1.14.3
Operating System: linux
GOPATH=/home/ia/go
GOROOT=/home/ia/go1.14.3.linux-amd64

This PR doesn't modify the behavior of --keystore in this context at all. It just enables using the dev mode with a specific key instead of an always-new random one.

Since the default value for the dev mode keystore is a temporary /tmp/go-ethereum-key.xxx directory, in order to interact with the mainnet keystore the user would need to explicity set --keystore=~/.ethereum/keystore or --datadir=~/.ethereum, both of which seem fairly unreasonable and unlikely to me.

I for one have found this feature useful for development. Having the ability to use a static key (or set of keys) just decrements the number of variables you may need to manage.

[karalabe]

I'll pick this up. While I agree that dev mode shouldn't be made smart, we already support persistency, this just supports custom password or pointing a dev chain to an existing account. I can imagine that might be useful in some integration test with hard coded accs, so ok by me. The code is also super tiny and localized, so +1.

[karalabe]

LGTM

[karalabe]

Flags need to be deduplicated.

[karalabe]

Thanks for the PR!

[zrock23]

I have a question in version 1.9.25 where can I find the generated passphrase in dev mode?
windows:geth.exe --dev --dev.period 1

[meowsbits]

With those commands, the passphrase should be empty (""), ie no passphrase. You can set one using the --password file option, eg.

echo foo > pass.txt
geth.exe --dev --dev.period 1 --password ./pass.txt