cli, rpc: add -rpcid option for custom request IDs

diff --git a/src/bitcoin-cli.cpp b/src/bitcoin-cli.cpp
index cc195226..3455aea7 100644
--- a/src/bitcoin-cli.cpp
+++ b/src/bitcoin-cli.cpp
@@ -57,6 +57,7 @@ using CliClock = std::chrono::system_clock;
 const TranslateFn G_TRANSLATION_FUN{nullptr};
 
 static const char DEFAULT_RPCCONNECT[] = "127.0.0.1";
+static constexpr const char* DEFAULT_RPC_REQ_ID{"1"};
 static const int DEFAULT_HTTP_CLIENT_TIMEOUT=900;
 static constexpr int DEFAULT_WAIT_CLIENT_TIMEOUT = 0;
 static const bool DEFAULT_NAMED=false;
@@ -100,6 +101,7 @@ static void SetupCliArgs(ArgsManager& argsman)
     SetupChainParamsBaseOptions(argsman);
     argsman.AddArg("-color=<when>", strprintf("Color setting for CLI output (default: %s). Valid values: always, auto (add color codes when standard output is connected to a terminal and OS is not WIN32), never. Only applies to the output of -getinfo.", DEFAULT_COLOR_SETTING), ArgsManager::ALLOW_ANY | ArgsManager::DISALLOW_NEGATION, OptionsCategory::OPTIONS);
     argsman.AddArg("-named", strprintf("Pass named instead of positional arguments (default: %s)", DEFAULT_NAMED), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
+    argsman.AddArg("-rpcid=<id>", strprintf("Set a custom JSON-RPC request ID string (default: %s)", DEFAULT_RPC_REQ_ID), ArgsManager::ALLOW_ANY | ArgsManager::DISALLOW_NEGATION | ArgsManager::DISALLOW_ELISION, OptionsCategory::OPTIONS);
     argsman.AddArg("-rpcclienttimeout=<n>", strprintf("Timeout in seconds during HTTP requests, or 0 for no timeout. (default: %d)", DEFAULT_HTTP_CLIENT_TIMEOUT), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-rpcconnect=<ip>", strprintf("Send commands to node running on <ip> (default: %s)", DEFAULT_RPCCONNECT), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-rpccookiefile=<loc>", "Location of the auth cookie. Relative paths will be prefixed by a net-specific datadir location. (default: data dir)", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
@@ -787,7 +789,8 @@ struct DefaultRequestHandler : BaseRequestHandler {
         } else {
             params = RPCConvertValues(method, args);
         }
-        return JSONRPCRequestObj(method, params, 1);
+        UniValue id{UniValue::VSTR, gArgs.GetArg("-rpcid", DEFAULT_RPC_REQ_ID)};
+        return JSONRPCRequestObj(method, params, id);
     }
 
     UniValue ProcessReply(const UniValue &reply) override
diff --git a/src/rpc/request.cpp b/src/rpc/request.cpp
index 34a9ff75..d162263e 100644
--- a/src/rpc/request.cpp
+++ b/src/rpc/request.cpp
@@ -233,11 +233,13 @@ void JSONRPCRequest::parse(const UniValue& valRequest)
     if (!valMethod.isStr())
         throw JSONRPCError(RPC_INVALID_REQUEST, "Method must be a string");
     strMethod = valMethod.get_str();
+    const std::string log_id{id && !id->isNull() ? SanitizeString(id->getValStr()) : ""};
     if (fLogIPs)
-        LogDebug(BCLog::RPC, "ThreadRPCServer method=%s user=%s peeraddr=%s\n", SanitizeString(strMethod),
-            this->authUser, this->peerAddr);
+        LogDebug(BCLog::RPC, "ThreadRPCServer method=%s user=%s peeraddr=%s id=%s", SanitizeString(strMethod),
+            this->authUser, this->peerAddr, log_id);
     else
-        LogDebug(BCLog::RPC, "ThreadRPCServer method=%s user=%s\n", SanitizeString(strMethod), this->authUser);
+        LogDebug(BCLog::RPC, "ThreadRPCServer method=%s user=%s id=%s", SanitizeString(strMethod), this->authUser,
+            log_id);
 
     // Parse params
     const UniValue& valParams{request.find_value("params")};
diff --git a/test/functional/interface_bitcoin_cli.py b/test/functional/interface_bitcoin_cli.py
index 953eea3d..e908ba8a 100755
--- a/test/functional/interface_bitcoin_cli.py
+++ b/test/functional/interface_bitcoin_cli.py
@@ -421,6 +421,18 @@ class TestBitcoinCli(BitcoinTestFramework):
 
         self.test_netinfo()
 
+        self.log.info("Test -rpcid option sets custom JSON-RPC request ID")
+        with self.nodes[0].assert_debug_log(expected_msgs=['id=myrpcid']):
+            self.nodes[0].cli('-rpcid=myrpcid').getblockcount()
+
+        self.log.info("Test default request logs default id=1")
+        with self.nodes[0].assert_debug_log(expected_msgs=["ThreadRPCServer method=getblockcount", "id=1"]):
+            self.nodes[0].cli.getblockcount()
+
+        self.log.info("Test that request ids with unsafe characters are sanitized in the log")
+        with self.nodes[0].assert_debug_log(expected_msgs=["ThreadRPCServer method=getblockcount", "id=abcdef"]):
+            self.nodes[0].cli('-rpcid=abc<\n>def').getblockcount()
+
         self.log.info("Test -version with node stopped")
         self.stop_node(0)
         cli_response = self.nodes[0].cli('-version').send_cli()