Improve CLI, adapt tests, update documentation

src/util/error.rs

@@ -47,8 +47,14 @@ pub enum Error {
 	#[error(display = "Timeout")]
 	Timeout,
 
-	#[error(display = "Too many errors: {:?}", _0)]
-	TooManyErrors(Vec<String>),
+	#[error(
+		display = "Could not reach quorum of {}. {} of {} request succeeded, others returned errors: {:?}",
+		_0,
+		_1,
+		_2,
+		_3
+	)]
+	Quorum(usize, usize, usize, Vec<String>),
 
 	#[error(display = "Bad RPC: {}", _0)]
 	BadRpc(String),
@@ -81,6 +87,35 @@ impl<T> From<tokio::sync::mpsc::error::SendError<T>> for Error {
 	}
 }
 
+impl<'a> From<&'a str> for Error {
+	fn from(v: &'a str) -> Error {
+		Error::Message(v.to_string())
+	}
+}
+
+impl From<String> for Error {
+	fn from(v: String) -> Error {
+		Error::Message(v)
+	}
+}
+
+pub trait ErrorContext<T, E> {
+	fn err_context<C: std::borrow::Borrow<str>>(self, ctx: C) -> Result<T, Error>;
+}
+
+impl<T, E> ErrorContext<T, E> for Result<T, E>
+where
+	E: std::fmt::Display,
+{
+	#[inline]
+	fn err_context<C: std::borrow::Borrow<str>>(self, ctx: C) -> Result<T, Error> {
+		match self {
+			Ok(x) => Ok(x),
+			Err(e) => Err(Error::Message(format!("{}\n{}", ctx.borrow(), e))),
+		}
+	}
+}
+
 // Custom serialization for our error type, for use in RPC.
 // Errors are serialized as a string of their Display representation.
 // Upon deserialization, they all become a RemoteError with the