cln-plugin: include the full error chain when given a context

Changelog-None

Author: daywalker90

plugins/examples/cln-plugin-startup.rs

@@ -2,12 +2,14 @@
 //! plugins using the Rust API against Core Lightning.
 #[macro_use]
 extern crate serde_json;
+use anyhow::Context;
 use cln_plugin::options::{
     self, BooleanConfigOption, DefaultIntegerArrayConfigOption, DefaultIntegerConfigOption,
     DefaultStringArrayConfigOption, IntegerArrayConfigOption, IntegerConfigOption,
     StringArrayConfigOption,
 };
 use cln_plugin::{Builder, Error, HookBuilder, Plugin, messages};
+use cln_rpc::ClnRpc;
 
 const TEST_NOTIF_TAG: &str = "test_custom_notification";
 
@@ -77,6 +79,7 @@ async fn main() -> Result<(), anyhow::Error> {
             test_send_custom_notification,
         )
         .rpcmethod("test-log-levels", "send on all log levels", test_log_levels)
+        .rpcmethod("test-error", "test error with context", test_error)
         .subscribe("connect", connect_handler)
         .subscribe("test_custom_notification", test_receive_custom_notification)
         .hook_from_builder(
@@ -179,3 +182,12 @@ async fn test_log_levels(
     log::error!("log::error! working");
     Ok(json!({}))
 }
+
+async fn test_error(p: Plugin<()>, _v: serde_json::Value) -> Result<serde_json::Value, Error> {
+    let mut rpc = ClnRpc::new(p.configuration().rpc_file).await?;
+    let gi: serde_json::Value = rpc
+        .call_raw("00000000000", &json!({}))
+        .await
+        .context("context given")?;
+    Ok(gi)
+}

plugins/src/lib.rs

@@ -2,8 +2,8 @@ use crate::codec::{JsonCodec, JsonRpcCodec};
 pub use anyhow::anyhow;
 use anyhow::{Context, Result};
 use futures::sink::SinkExt;
-use serde::de::DeserializeOwned;
 use serde::Serialize;
+use serde::de::DeserializeOwned;
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
 extern crate log;
 use log::trace;
@@ -973,7 +973,7 @@ where
                                     .send(json!({
                                     "jsonrpc": "2.0",
                                     "id": id,
-                                    "error": parse_error(e.to_string()),
+                                    "error": parse_error(&e),
                                     }))
                                     .await
                                     .context("returning custom error"),
@@ -1112,14 +1112,20 @@ struct RpcError {
     pub message: String,
     pub data: Option<serde_json::Value>,
 }
-fn parse_error(error: String) -> RpcError {
-    match serde_json::from_str::<RpcError>(&error) {
-        Ok(o) => o,
-        Err(_) => RpcError {
+fn parse_error(error: &anyhow::Error) -> RpcError {
+    if let Ok(o) = serde_json::from_str::<RpcError>(&error.to_string()) {
+        o
+    } else {
+        let message = error
+            .chain()
+            .map(std::string::ToString::to_string)
+            .collect::<Vec<_>>()
+            .join(": ");
+        RpcError {
             code: Some(-32700),
-            message: error,
+            message,
             data: None,
-        },
+        }
     }
 }
 
@@ -1133,4 +1139,19 @@ mod test {
         let builder = Builder::new(tokio::io::stdin(), tokio::io::stdout());
         let _ = builder.start(state);
     }
+    #[test]
+    fn parse_error_includes_full_anyhow_chain() {
+        let err = anyhow!("No such file or directory (os error 2)")
+            .context("config file missing")
+            .context("failed to load config");
+
+        let rpc_error = parse_error(&err);
+
+        assert_eq!(rpc_error.code, Some(-32700));
+        assert_eq!(
+            rpc_error.message,
+            "failed to load config: config file missing: No such file or directory (os error 2)"
+        );
+        assert_eq!(rpc_error.data, None);
+    }
 }

tests/test_cln_rs.py

@@ -78,6 +78,9 @@ def test_plugin_start(node_factory):
     assert not l1.rpc.listconfigs("test-dynamic-option")["configs"]["test-dynamic-option"]["value_bool"]
     wait_for(lambda: l1.daemon.is_in_log(r'cln-plugin-startup: Got dynamic option change: test-dynamic-option "false"'))
 
+    with pytest.raises(RpcError, match="context given: .* Unknown command"):
+        l1.rpc.test_error()
+
 
 def test_plugin_options_handle_defaults(node_factory):
     """Start a minimal plugin and ensure it is well-behaved