⚙️ refactor: add new pooling error type for pooling code (#180)(#178)

src/cache/error.rs

@@ -0,0 +1,40 @@
+//! This module provides the error enum to handle different errors associated while requesting data from
+//! the redis server using an async connection pool.
+use std::fmt;
+
+use redis::RedisError;
+
+/// A custom error type used for handling redis async pool associated errors.
+///
+/// This enum provides variants three different categories of errors:
+/// * `RedisError` - This variant handles all errors related to `RedisError`,
+/// * `PoolExhaustionWithConnectionDropError` - This variant handles the error
+/// which occurs when all the connections in the connection pool return a connection
+/// dropped redis error.
+#[derive(Debug)]
+pub enum PoolError {
+    RedisError(RedisError),
+    PoolExhaustionWithConnectionDropError,
+}
+
+impl fmt::Display for PoolError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            PoolError::RedisError(redis_error) => {
+                if let Some(detail) = redis_error.detail() {
+                    write!(f, "{}", detail)
+                } else {
+                    write!(f, "")
+                }
+            }
+            PoolError::PoolExhaustionWithConnectionDropError => {
+                write!(
+                    f,
+                    "Error all connections from the pool dropped with connection error"
+                )
+            }
+        }
+    }
+}
+
+impl error_stack::Context for PoolError {}