bit better error handling

src/error.rs

@@ -1,34 +1,50 @@
-
 pub enum ErrorKind {
-    InvalidEndpoint,
+    InvalidEndpointError,
     JsonParseError,
+    DatabaseError,
 }
 
 pub struct Error {
     kind: ErrorKind,
+    desc: Option<String>,
 }
 
 impl Error {
     pub fn new(kind: ErrorKind) -> Error {
-        Error {
-            kind,
-        }
-    }
-}
-
-impl From<serde_json::Error> for Error {
-    fn from(_: serde_json::Error) -> Self {
-        Error {
-            kind: ErrorKind::JsonParseError,
-        }
+        Error { kind, desc: None }
     }
 }
 
 impl ToString for Error {
     fn to_string(&self) -> String {
-        match self.kind {
-            ErrorKind::InvalidEndpoint => "invalid endpoint",
-            ErrorKind::JsonParseError => "JSON parse error",
-        }.to_string()
+        let mut error = match self.kind {
+            ErrorKind::InvalidEndpointError => "invalid endpoint",
+            ErrorKind::JsonParseError => "unable to parse JSON data",
+            ErrorKind::DatabaseError => "unable to connect to database",
+        }
+        .to_string();
+        if let Some(desc) = &self.desc {
+            error += ": ";
+            error += desc;
+        }
+        error
+    }
+}
+
+impl From<serde_json::Error> for Error {
+    fn from(error: serde_json::Error) -> Self {
+        Error {
+            kind: ErrorKind::JsonParseError,
+            desc: Some(error.to_string()),
+        }
+    }
+}
+
+impl From<r2d2::Error> for Error {
+    fn from(error: r2d2::Error) -> Self {
+        Error {
+            kind: ErrorKind::DatabaseError,
+            desc: Some(error.to_string()),
+        }
     }
 }