feat(drainer): added drainer which reads from redis stream and executes queries on DB (#142)

crates/drainer/src/errors.rs

@@ -0,0 +1,19 @@
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum DrainerError {
+    #[error("Error in parsing config : {0}")]
+    ConfigParsingError(String),
+    #[error("Error fetching stream length for stream : {0}")]
+    StreamGetLengthError(String),
+    #[error("Error reading from stream : {0}")]
+    StreamReadError(String),
+    #[error("Error triming from stream: {0}")]
+    StreamTrimFailed(String),
+    #[error("No entries found for stream: {0}")]
+    NoStreamEntry(String),
+    #[error("Error in making stream: {0} available")]
+    DeleteKeyFailed(String),
+}
+
+pub type DrainerResult<T> = error_stack::Result<T, DrainerError>;