Add tool and script for interop testing (#3417)

* add tool and script for interop testing

* identity

* lint

* merge upstream, fix conflict, update script, add comment

* add comma separated support for --peer=

* remove NUM_VALIDATORS, comma fix

* WIP docker image

* use CI builder

* pr feedback

* whatever antoine says

* ignore git in docker

* jobs=auto

* disable remote cache

* try to cache the golang part

* try to cache the golang part

* nvm

* From Antoine with love

* fix

tools/interop/convert-keys/main.go

@@ -0,0 +1,65 @@
+// Used for converting keys.yaml files from eth2.0-pm for interop testing.
+// See: https://github.com/ethereum/eth2.0-pm/tree/master/interop/mocked_start
+//
+// This code can be discarded after interop testing.
+package main
+
+import (
+	"encoding/hex"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+
+	"gopkg.in/yaml.v2"
+	keygen "github.com/prysmaticlabs/prysm/tools/unencrypted-keys-gen"
+)
+
+// KeyPair with hex encoded data.
+type KeyPair struct {
+	Priv string `yaml:"privkey"`
+	Pub  string `yaml:"pubkey"`
+}
+
+// KeyPairs represent the data format in the upstream yaml.
+type KeyPairs []KeyPair
+
+func main() {
+	if len(os.Args) < 3 {
+		fmt.Println("Usage: convert-keys path/to/keys.yaml path/to/output.json")
+		return
+	}
+	inFile := os.Args[1]
+
+	in, err := ioutil.ReadFile(inFile)
+	if err != nil {
+		log.Fatalf("Failed to read file %s: %v", inFile, err)
+	}
+	data := make(KeyPairs, 0)
+	if err := yaml.Unmarshal(in, &data); err != nil {
+		log.Fatalf("Failed to unmarshal yaml: %v", err)
+	}
+
+	out := &keygen.UnencryptedKeysContainer{}
+	for _, key := range data {
+		pk, err := hex.DecodeString(key.Priv[2:])
+		if err != nil {
+			log.Fatalf("Failed to decode hex string %s: %v", key.Priv, err)
+		}
+
+		out.Keys = append(out.Keys, &keygen.UnencryptedKeys{
+			ValidatorKey: pk,
+			WithdrawalKey: pk,
+		})
+	}
+
+	outFile, err := os.Create(os.Args[2])
+	if err != nil {
+		log.Fatalf("Failed to create file at %s: %v", os.Args[2], err)
+	}
+	defer outFile.Close()
+	if err := keygen.SaveUnencryptedKeysToFile(outFile, out); err != nil {
+		log.Fatalf("Failed to save %v", err)
+	}
+	log.Printf("Wrote %s\n", os.Args[2])
+}