Support binary in `—p2p-private-key-file option

Author: courtneyeh

Diff for: networking/p2p/src/main/java/tech/pegasys/teku/networking/p2p/network/config/FilePrivateKeySource.java

@@ -37,7 +37,7 @@ public Bytes getOrGeneratePrivateKeyBytes() {
     try {
       File file = new File(fileName);
       if (!file.createNewFile()) {
-        return getPrivateKeyBytesFromFile();
+        return getPrivateKeyBytesFromTextFile();
       }
       final PrivKey privKey = KeyKt.generateKeyPair(KeyType.SECP256K1).component1();
       final Bytes privateKeyBytes = Bytes.wrap(KeyKt.marshalPrivateKey(privKey));
@@ -51,11 +51,21 @@ public Bytes getOrGeneratePrivateKeyBytes() {
     }
   }
 
-  private Bytes getPrivateKeyBytesFromFile() {
+  private Bytes getPrivateKeyBytesFromTextFile() {
     try {
       final Bytes privateKeyBytes = Bytes.fromHexString(Files.readString(Paths.get(fileName)));
       STATUS_LOG.usingGeneratedP2pPrivateKey(fileName, false);
       return privateKeyBytes;
+    } catch (IOException e) {
+      return getPrivateKeyBytesFromBytesFile();
+    }
+  }
+
+  private Bytes getPrivateKeyBytesFromBytesFile() {
+    try {
+      final Bytes privateKeyBytes = Bytes.wrap(Files.readAllBytes(Paths.get(fileName)));
+      STATUS_LOG.usingGeneratedP2pPrivateKey(fileName, false);
+      return privateKeyBytes;
     } catch (IOException e) {
       throw new RuntimeException("p2p private key file not found - " + fileName);
     }

Diff for: networking/p2p/src/test/java/tech/pegasys/teku/networking/p2p/network/config/FilePrivateKeySourceTest.java

@@ -37,7 +37,7 @@ void shouldCreateKeyAndSaveToFile(@TempDir Path tempDir) throws IOException {
   }
 
   @Test
-  void shouldGetKeyFromSavedFile(@TempDir Path tempDir) throws IOException {
+  void shouldGetKeyFromSavedTextFile(@TempDir Path tempDir) throws IOException {
     final Path file = tempDir.resolve("file.txt");
     final Bytes privateKey = Bytes.wrap(PrivateKeyGenerator.generate().bytes());
     Files.writeString(file, privateKey.toHexString());
@@ -46,6 +46,16 @@ void shouldGetKeyFromSavedFile(@TempDir Path tempDir) throws IOException {
     assertThat(privateKeySource.getOrGeneratePrivateKeyBytes()).isEqualTo(privateKey);
   }
 
+  @Test
+  void shouldGetKeyFromBinaryFile(@TempDir Path tempDir) throws IOException {
+    final Path file = tempDir.resolve("file.dat");
+    final Bytes privateKey = Bytes.wrap(PrivateKeyGenerator.generate().bytes());
+    Files.write(file, privateKey.toArray());
+    final PrivateKeySource privateKeySource = new FilePrivateKeySource(file.toString());
+
+    assertThat(privateKeySource.getOrGeneratePrivateKeyBytes()).isEqualTo(privateKey);
+  }
+
   @Test
   void shouldThrowExceptionIfInvalidFileName(@TempDir Path tempDir) {
     final PrivateKeySource privateKeySource =