cmd/ethermint: use default Genesis when necessary

Requires tendermint/tmlibs#35
Fixes cosmos#244

Act like `tendermint init` so that if we don't have
a genesis-path, and also move to $HOME/.ethermint/keystore, the
files that are currently contained in
$GOPATH/src/github.com/tendermint/ethermint/setup/keystore

Therefore now `ethermint init` should be one step e.g
```shell
$ ethermint --datadir ~/.ethermint init
```
instead of the formerly tedious
```shell
$ cd $GOPATH/src/github.com/tendermint/ethermint
$ ethermint --datadir ~/.ethermint init setup/genesis.json
$ cp -r setup/keystore ~/.ethermint
```

README.md

@@ -103,13 +103,14 @@ these instructions.
 ```bash
 tendermint init --home ~/.ethermint/tendermint
 
-cd $GOPATH/src/github.com/tendermint/ethermint
-
-ethermint --datadir ~/.ethermint init setup/genesis.json
+ethermint --datadir ~/.ethermint init
+```
 
-cp -r setup/keystore ~/.ethermint
+* Note:
+You can optionally copy a keystore to the Ethereum folder that you used in the steps above i.e `~/.ethermint` e.g
+```bash
+cp -r keystore ~/.ethermint
 ```
-In the last step we copy the private key from the initialisation folder into the actual ethereum folder. 
 
 
 ### Running

cmd/ethermint/init.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"encoding/json"
 	"os"
 	"path/filepath"
 
@@ -13,29 +12,19 @@ import (
 	"github.com/ethereum/go-ethereum/log"
 
 	emtUtils "github.com/tendermint/ethermint/cmd/utils"
+	"github.com/tendermint/tmlibs/common"
 )
 
 // nolint: vetshadow
 func initCmd(ctx *cli.Context) error {
-
-	// ethereum genesis.json
 	genesisPath := ctx.Args().First()
-	if len(genesisPath) == 0 {
-		ethUtils.Fatalf("must supply path to genesis JSON file")
-	}
-
-	file, err := os.Open(genesisPath)
+	genesis, err := common.ParseGenesisOrDefault(genesisPath)
 	if err != nil {
-		ethUtils.Fatalf("Failed to read genesis file: %v", err)
+		ethUtils.Fatalf("genesisJSON err: %v", err)
 	}
-	defer file.Close() // nolint: errcheck
 
-	genesis := new(core.Genesis)
-	if err := json.NewDecoder(file).Decode(genesis); err != nil {
-		ethUtils.Fatalf("invalid genesis file: %v", err)
-	}
-
-	chainDb, err := ethdb.NewLDBDatabase(filepath.Join(emtUtils.MakeDataDir(ctx), "ethermint/chaindata"), 0, 0)
+	ethermintDataDir := emtUtils.MakeDataDir(ctx)
+	chainDb, err := ethdb.NewLDBDatabase(filepath.Join(ethermintDataDir, "ethermint/chaindata"), 0, 0)
 	if err != nil {
 		ethUtils.Fatalf("could not open database: %v", err)
 	}
@@ -46,5 +35,46 @@ func initCmd(ctx *cli.Context) error {
 	}
 
 	log.Info("successfully wrote genesis block and/or chain rule set", "hash", hash)
+
+	// As per https://github.com/tendermint/ethermint/issues/244#issuecomment-322024199
+	// Let's implicitly add in the respective keystore files
+	// to avoid manually doing this step:
+	// $ cp -r $GOPATH/src/github.com/tendermint/ethermint/setup/keystore $(DATADIR)
+	keystoreDir := filepath.Join(ethermintDataDir, "keystore")
+	if err := os.MkdirAll(keystoreDir, 0777); err != nil {
+		ethUtils.Fatalf("mkdirAll keyStoreDir: %v", err)
+	}
+
+	for filename, content := range keystoreFilesMap {
+		storeFileName := filepath.Join(keystoreDir, filename)
+		f, err := os.Create(storeFileName)
+		if err != nil {
+			log.Error("create %q err: %v", storeFileName, err)
+			continue
+		}
+		if _, err := f.Write([]byte(content)); err != nil {
+			log.Error("write content %q err: %v", storeFileName, err)
+		}
+		f.Close()
+	}
+
 	return nil
 }
+
+var keystoreFilesMap = map[string]string{
+	// https://github.com/tendermint/ethermint/blob/edc95f9d47ba1fb7c8161182533b5f5d5c5d619b/setup/keystore/UTC--2016-10-21T22-30-03.071787745Z--7eff122b94897ea5b0e2a9abf47b86337fafebdc
+	// OR
+	// $GOPATH/src/github.com/ethermint/setup/keystore/UTC--2016-10-21T22-30-03.071787745Z--7eff122b94897ea5b0e2a9abf47b86337fafebdc
+	"UTC--2016-10-21T22-30-03.071787745Z--7eff122b94897ea5b0e2a9abf47b86337fafebdc": `
+{
+  "address":"7eff122b94897ea5b0e2a9abf47b86337fafebdc",
+  "id":"f86a62b4-0621-4616-99af-c4b7f38fcc48","version":3,
+  "crypto":{
+    "cipher":"aes-128-ctr","ciphertext":"19de8a919e2f4cbdde2b7352ebd0be8ead2c87db35fc8e4c9acaf74aaaa57dad",
+    "cipherparams":{"iv":"ba2bd370d6c9d5845e92fbc6f951c792"},
+    "kdf":"scrypt","kdfparams":{"dklen":32,"n":262144,"p":1,"r":8,"salt":"c7cc2380a96adc9eb31d20bd8d8a7827199e8b16889582c0b9089da6a9f58e84"},
+    "mac":"ff2c0caf051ca15d8c43b6f321ec10bd99bd654ddcf12dd1a28f730cc3c13730"
+  }
+}
+`,
+}