Load wallet in monero-wallet-rpc on demand if necessary

Previously, we relied on the wallet in the `monero-wallet-rpc` daemon
to be loaded as we do on startup. As a consequence of this expectation,
restarting `monero-wallet-rpc` to fix bugs like #652 resulted in the
ASB no longer operating correctly.

To fix this, we now load the wallet on-demand in case the daemon responds
with the error code -13.

Ideally, we would implement this behaviour generically using the proxy
pattern on the `MoneroWalletRpc` trait. Unfortunately, when attempting
to do so we uncover a limitation in the design of `jsonrpc_client`.
This limitation is tracked in thomaseizinger/rust-jsonrpc-client#47.
Once fixed, we can implement this logic in a more robust way that is not
tied to the `check_tx_key` RPC call but applies to any RPC call automatically.

CHANGELOG.md

@@ -13,6 +13,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   The CLI expects to be connected to the ASB throughout the entire swap and hence reconnects as soon as the connection is closed.
   This resulted in a loop of connections being established but instantly closed again because the ASB deemed the connection to not be necessary.
   See issue https://github.com/comit-network/xmr-btc-swap/issues/648.
+- An issue where the ASB was unable to use the Monero wallet in case `monero-wallet-rpc` has been restarted.
+  In case no wallet is loaded when we try to interact with the `monero-wallet-rpc` daemon, we now load the correct wallet on-demand.
+  See issue https://github.com/comit-network/xmr-btc-swap/issues/652.
 
 ## [0.8.1] - 2021-08-16
 

monero-rpc/src/lib.rs

@@ -14,3 +14,5 @@
 
 pub mod monerod;
 pub mod wallet;
+
+pub use jsonrpc_client as jsonrpc;