Poll bitcoind at startup

When we start, bitcoind may not be ready to handle requests if we restarted
it around the same time. We thus poll it for 30 seconds before giving up.
This is especially useful for tests (e.g. on regtest).

eclair-core/src/main/scala/fr/acinq/eclair/Setup.scala

@@ -134,12 +134,9 @@ class Setup(val datadir: File,
       case "password" => BitcoinJsonRPCAuthMethod.UserPassword(config.getString("bitcoind.rpcuser"), config.getString("bitcoind.rpcpassword"))
     }
 
-    val bitcoinClient = new BasicBitcoinJsonRPCClient(
-      rpcAuthMethod = rpcAuthMethod,
-      host = config.getString("bitcoind.host"),
-      port = config.getInt("bitcoind.rpcport"),
-      wallet = wallet)
-    val future = for {
+    case class BitcoinStatus(version: Int, chainHash: ByteVector32, initialBlockDownload: Boolean, verificationProgress: Double, blockCount: Long, headerCount: Long, unspentAddresses: List[String])
+
+    def getBitcoinStatus(bitcoinClient: BasicBitcoinJsonRPCClient): Future[BitcoinStatus] = for {
       json <- bitcoinClient.invoke("getblockchaininfo").recover { case e => throw BitcoinRPCConnectionException(e) }
       // Make sure wallet support is enabled in bitcoind.
       wallets <- bitcoinClient.invoke("listwallets").recover { case e => throw BitcoinWalletDisabledException(e) }
@@ -164,9 +161,24 @@ class Setup(val datadir: File,
         case "signet" => bitcoinClient.invoke("getrawtransaction", "ff1027486b628b2d160859205a3401fb2ee379b43527153b0b50a92c17ee7955") // coinbase of #5000
         case "regtest" => Future.successful(())
       }
-    } yield (progress, ibd, chainHash, bitcoinVersion, unspentAddresses, blocks, headers)
-    // blocking sanity checks
-    val (progress, initialBlockDownload, chainHash, bitcoinVersion, unspentAddresses, blocks, headers) = await(future, 30 seconds, "bitcoind did not respond after 30 seconds")
+    } yield BitcoinStatus(bitcoinVersion, chainHash, ibd, progress, blocks, headers, unspentAddresses)
+
+    def pollBitcoinStatus(bitcoinClient: BasicBitcoinJsonRPCClient): Future[BitcoinStatus] = {
+      getBitcoinStatus(bitcoinClient).transformWith {
+        case Success(status) => Future.successful(status)
+        case Failure(e) =>
+          logger.warn(s"failed to connect to bitcoind (${e.getMessage}), retrying...")
+          after(5 seconds) { pollBitcoinStatus(bitcoinClient) }
+      }
+    }
+
+    val bitcoinClient = new BasicBitcoinJsonRPCClient(
+      rpcAuthMethod = rpcAuthMethod,
+      host = config.getString("bitcoind.host"),
+      port = config.getInt("bitcoind.rpcport"),
+      wallet = wallet
+    )
+    val BitcoinStatus(bitcoinVersion, chainHash, initialBlockDownload, progress, blocks, headers, unspentAddresses) = await(pollBitcoinStatus(bitcoinClient), 30 seconds, "bitcoind did not respond after 30 seconds")
     logger.info(s"bitcoind version=$bitcoinVersion")
     assert(bitcoinVersion >= 230000, "Eclair requires Bitcoin Core 23.0 or higher")
     assert(unspentAddresses.forall(address => !isPay2PubkeyHash(address)), "Your wallet contains non-segwit UTXOs. You must send those UTXOs to a bech32 address to use Eclair (check out our README for more details).")