refactor(error): various minor changes

Author: omarabid

examples/error.rs

@@ -16,7 +16,16 @@ fn fibonacci(n: u64) -> u64 {
 }
 
 fn main() -> Result<()> {
+// Force rustc to display the log messages in the console.
+    std::env::set_var("RUST_LOG", "trace");
+
+    // Initialize the logger.
+    pretty_env_logger::init_timed();
+
     // This example should fail and return an error.
+    println!("This example should fail and return an error.");
+    println!("Run this with: RUST_BACKTRACE=1 cargo run --example error");
+
     let mut agent = PyroscopeAgent::builder("http://invalid_url", "example.error")
         .build()?;
     // Start Agent

src/backends/pprof.rs

@@ -8,6 +8,7 @@ use pprof::{ProfilerGuard, ProfilerGuardBuilder, Report};
 
 use crate::backends::Backend;
 use crate::backends::State;
+use crate::PyroscopeError;
 use crate::Result;
 
 #[derive(Default)]
@@ -31,10 +32,7 @@ impl Backend for Pprof<'_> {
     fn initialize(&mut self, sample_rate: i32) -> Result<()> {
         // Check if Backend is Uninitialized
         if self.state != State::Uninitialized {
-            //return Err(crate::error::PyroscopeError {
-                //msg: String::from("Pprof Backend is already Initialized"),
-            //});
-            return Err(crate::error::PyroscopeError::default());
+            return Err(PyroscopeError::new("Pprof Backend is already Initialized"));
         }
 
         // Construct a ProfilerGuardBuilder
@@ -51,10 +49,7 @@ impl Backend for Pprof<'_> {
     fn start(&mut self) -> Result<()> {
         // Check if Backend is Ready
         if self.state != State::Ready {
-            //return Err(crate::error::PyroscopeError {
-                //msg: String::from("Pprof Backend is not Ready"),
-            //});
-            return Err(crate::error::PyroscopeError::default());
+            return Err(PyroscopeError::new("Pprof Backend is not Ready"));
         }
 
         self.guard = Some(self.inner_builder.as_ref().unwrap().clone().build()?);
@@ -68,11 +63,7 @@ impl Backend for Pprof<'_> {
     fn stop(&mut self) -> Result<()> {
         // Check if Backend is Running
         if self.state != State::Running {
-            //return Err(crate::error::PyroscopeError {
-                //msg: String::from("Pprof Backend is not Running"),
-            //});
-
-            return Err(crate::error::PyroscopeError::default());
+            return Err(PyroscopeError::new("Pprof Backend is not Running"));
         }
 
         // drop the guard
@@ -87,10 +78,7 @@ impl Backend for Pprof<'_> {
     fn report(&mut self) -> Result<Vec<u8>> {
         // Check if Backend is Running
         if self.state != State::Running {
-            //return Err(crate::error::PyroscopeError {
-                //msg: String::from("Pprof Backend is not Running"),
-            //});
-            return Err(crate::error::PyroscopeError::default());
+            return Err(PyroscopeError::new("Pprof Backend is not Running"));
         }
 
         let mut buffer = Vec::new();
@@ -107,7 +95,9 @@ impl Backend for Pprof<'_> {
 
 // Copyright: https://github.com/YangKeao
 fn fold<W>(report: &Report, with_thread_name: bool, mut writer: W) -> Result<()>
-where W: std::io::Write {
+where
+    W: std::io::Write,
+{
     for (key, value) in report.data.iter() {
         if with_thread_name {
             if !key.thread_name.is_empty() {

src/error.rs

@@ -32,6 +32,24 @@ impl Default for PyroscopeError {
     }
 }
 
+impl PyroscopeError {
+    /// Create a new instance of PyroscopeError
+    pub fn new(msg: &str) -> Self {
+        PyroscopeError {
+            msg: msg.to_string(),
+            source: None,
+        }
+    }
+
+    /// Create a new instance of PyroscopeError with source
+    pub fn new_with_source(msg: &str, source: Box<dyn std::error::Error + Send + Sync>) -> Self {
+        PyroscopeError {
+            msg: msg.to_string(),
+            source: Some(source),
+        }
+    }
+}
+
 impl From<reqwest::Error> for PyroscopeError {
     fn from(err: reqwest::Error) -> Self {
         PyroscopeError {
@@ -71,17 +89,17 @@ impl From<std::io::Error> for PyroscopeError {
 impl<T> From<std::sync::PoisonError<T>> for PyroscopeError {
     fn from(_err: std::sync::PoisonError<T>) -> Self {
         PyroscopeError {
-            msg: String::from("Poison/Mutex Error"),
+            msg: String::from("Poison Error"),
             source: None,
         }
     }
 }
 
-impl<T> From<std::sync::mpsc::SendError<T>> for PyroscopeError {
-    fn from(_err: std::sync::mpsc::SendError<T>) -> Self {
+impl<T: 'static + Send + Sync> From<std::sync::mpsc::SendError<T>> for PyroscopeError {
+    fn from(err: std::sync::mpsc::SendError<T>) -> Self {
         PyroscopeError {
-            msg: String::from("mpsc Send Error"),
-            source: None,
+            msg: String::from("SendError Error"),
+            source: Some(Box::new(err)),
         }
     }
 }