Add CLI pipe support for filtering command output

src/error.rs

@@ -6,13 +6,16 @@
 
 use indextree::NodeId;
 
+use crate::pipe::PipeError;
+
 #[derive(Debug)]
 pub enum Error {
     Parser(ParserError),
     EditConfig(yang4::Error),
     ValidateConfig(yang4::Error),
-    Callback(String),
+    Callback(CallbackError),
     Backend(tonic::Status),
+    Pipe(PipeError),
 }
 
 #[derive(Debug)]
@@ -22,6 +25,12 @@ pub enum ParserError {
     Ambiguous(Vec<NodeId>),
 }
 
+#[derive(Debug)]
+pub enum CallbackError {
+    BrokenPipe,
+    Other(String),
+}
+
 // ===== impl Error =====
 
 impl std::fmt::Display for Error {
@@ -40,6 +49,9 @@ impl std::fmt::Display for Error {
             Error::Backend(error) => {
                 write!(f, "{}", error)
             }
+            Error::Pipe(error) => {
+                write!(f, "{}", error)
+            }
         }
     }
 }
@@ -61,3 +73,30 @@ impl std::fmt::Display for ParserError {
 }
 
 impl std::error::Error for ParserError {}
+
+// ===== impl CallbackError =====
+
+impl std::fmt::Display for CallbackError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            CallbackError::BrokenPipe => write!(f, "broken pipe"),
+            CallbackError::Other(msg) => write!(f, "{}", msg),
+        }
+    }
+}
+
+impl From<String> for CallbackError {
+    fn from(s: String) -> Self {
+        CallbackError::Other(s)
+    }
+}
+
+impl From<std::io::Error> for CallbackError {
+    fn from(e: std::io::Error) -> Self {
+        if e.kind() == std::io::ErrorKind::BrokenPipe {
+            CallbackError::BrokenPipe
+        } else {
+            CallbackError::Other(e.to_string())
+        }
+    }
+}