Use strongly typed errors based on thiserror

Dyn<error> is generally discouraged in libraries.

Cargo.toml

@@ -21,6 +21,7 @@ reqwest = { version = "0.11.18", features = ["json", "multipart"] }
 serde = "1.0.183"
 serde_derive = "1.0.183"
 serde_json = "1.0.104"
+thiserror = "1.0.63"
 url = "2.4.0"
 
 [dev-dependencies]

examples/falcon_discover_hosts.rs

@@ -56,7 +56,7 @@ async fn main() {
             break;
         }
 
-        offset = offset + response.resources.len();
+        offset += response.resources.len();
 
         let batch_details = get_hosts(&falcon.cfg, response.resources)
             .await

src/apis/mod.rs

@@ -1,97 +1,34 @@
-use std::error;
-use std::fmt;
-
 #[derive(Debug, Clone)]
-pub struct ResponseContent<T> {
+pub struct ResponseContent<T: std::fmt::Debug> {
     pub status: reqwest::StatusCode,
     pub content: String,
     pub entity: Option<T>,
 }
 
-#[derive(Debug)]
-pub enum Error<T> {
-    Reqwest(reqwest::Error),
-    Serde(serde_json::Error),
-    Io(std::io::Error),
-    ResponseError(ResponseContent<T>),
-}
-
-impl<T> fmt::Display for Error<T> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        let (module, e) = match self {
-            Error::Reqwest(e) => ("reqwest", e.to_string()),
-            Error::Serde(e) => ("serde", e.to_string()),
-            Error::Io(e) => ("IO", e.to_string()),
-            Error::ResponseError(e) => ("response", format!("status code {}", e.status)),
-        };
-        write!(f, "error in {}: {}", module, e)
-    }
-}
-
-impl<T: fmt::Debug> error::Error for Error<T> {
-    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
-        Some(match self {
-            Error::Reqwest(e) => e,
-            Error::Serde(e) => e,
-            Error::Io(e) => e,
-            Error::ResponseError(_) => return None,
-        })
-    }
-}
-
-impl<T> From<reqwest::Error> for Error<T> {
-    fn from(e: reqwest::Error) -> Self {
-        Error::Reqwest(e)
+impl<T: std::fmt::Debug> std::fmt::Display for ResponseContent<T> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}: {:?} {:?}", self.status, self.content, self.entity)
     }
 }
 
-impl<T> From<serde_json::Error> for Error<T> {
-    fn from(e: serde_json::Error) -> Self {
-        Error::Serde(e)
-    }
-}
+impl<T: std::fmt::Debug> std::error::Error for ResponseContent<T> {}
 
-impl<T> From<std::io::Error> for Error<T> {
-    fn from(e: std::io::Error) -> Self {
-        Error::Io(e)
-    }
+#[derive(Debug, thiserror::Error)]
+pub enum Error<T: std::fmt::Debug> {
+    #[error("reqwest error: {0}")]
+    Reqwest(#[from] reqwest::Error),
+    #[error("serde error: {0}")]
+    Serde(#[from] serde_json::Error),
+    #[error("io error: {0}")]
+    Io(#[from] std::io::Error),
+    #[error("Response error: {0}")]
+    ResponseError(#[from] ResponseContent<T>),
 }
 
 pub fn urlencode<T: AsRef<str>>(s: T) -> String {
     ::url::form_urlencoded::byte_serialize(s.as_ref().as_bytes()).collect()
 }
 
-pub fn parse_deep_object(prefix: &str, value: &serde_json::Value) -> Vec<(String, String)> {
-    if let serde_json::Value::Object(object) = value {
-        let mut params = vec![];
-
-        for (key, value) in object {
-            match value {
-                serde_json::Value::Object(_) => params.append(&mut parse_deep_object(
-                    &format!("{}[{}]", prefix, key),
-                    value,
-                )),
-                serde_json::Value::Array(array) => {
-                    for (i, value) in array.iter().enumerate() {
-                        params.append(&mut parse_deep_object(
-                            &format!("{}[{}][{}]", prefix, key, i),
-                            value,
-                        ));
-                    }
-                }
-                serde_json::Value::String(s) => {
-                    params.push((format!("{}[{}]", prefix, key), s.clone()))
-                }
-                _ => params.push((format!("{}[{}]", prefix, key), value.to_string())),
-            }
-        }
-
-        return params;
-    }
-
-    unimplemented!("Only objects are supported with style=deepObject")
-}
-
 pub mod alerts_api;
 pub mod cloud_connect_aws_api;
 pub mod configuration_assessment_api;

src/easy/client.rs

@@ -2,7 +2,7 @@ use crate::apis::configuration::Configuration;
 use crate::apis::oauth2_api::{oauth2_access_token, Oauth2AccessTokenError};
 use crate::apis::Error;
 use crate::easy::cloud::FalconCloud;
-use crate::easy::errors::CredentialsError;
+use crate::error::CredentialsError;
 use std::env;
 
 #[derive(Clone)]
@@ -39,7 +39,7 @@ impl FalconHandle {
         Ok(())
     }
 
-    pub async fn from_env() -> Result<Self, Box<dyn std::error::Error>> {
+    pub async fn from_env() -> Result<Self, crate::error::CredentialsError> {
         Ok(FalconHandle::from_cfg(Credentials::from_env()?).await?)
     }
 }
@@ -54,19 +54,10 @@ pub struct Credentials {
 
 impl Credentials {
     pub fn from_env() -> Result<Self, CredentialsError> {
-        let client_id = env::var("FALCON_CLIENT_ID").map_err(|_| {
-            CredentialsError(
-                "Missing FALCON_CLIENT_ID environment variable. Please provide your OAuth2 API Client Secret for authentication with CrowdStrike Falcon platform. Establishing and retrieving OAuth2 API credentials can be performed at https://falcon.crowdstrike.com/support/api-clients-and-keys."
-                    .to_string(),
-            )
-        })?;
+        let client_id = env::var("FALCON_CLIENT_ID").map_err(|_| CredentialsError::ClientID)?;
 
-        let client_secret = env::var("FALCON_CLIENT_SECRET").map_err(|_| {
-            CredentialsError(
-                "Missing FALCON_CLIENT_SECRET environment variable. Please provide your OAuth2 API Client Secret for authentication with CrowdStrike Falcon platform. Establishing and retrieving OAuth2 API credentials can be performed at https://falcon.crowdstrike.com/support/api-clients-and-keys."
-                    .to_string(),
-            )
-        })?;
+        let client_secret =
+            env::var("FALCON_CLIENT_SECRET").map_err(|_| CredentialsError::Secret)?;
         let member_cid = env::var("FALCON_MEMBER_CID").ok();
 
         Ok(Credentials {

src/easy/cloud.rs

@@ -1,6 +1,7 @@
-use crate::easy::errors::CredentialsError;
 use std::{env, str::FromStr};
 
+use crate::error::CredentialsError;
+
 #[derive(Debug, Clone, Copy)]
 pub enum FalconCloud {
     Us1,
@@ -24,7 +25,7 @@ impl FalconCloud {
     }
 
     pub fn from_env() -> Result<Self, CredentialsError> {
-        let cloud_str = env::var("FALCON_CLOUD").map_err(|_| CredentialsError("Missing FALCON_CLOUD environment variable. Please provide your Falcon Cloud region".to_string()))?;
+        let cloud_str = env::var("FALCON_CLOUD").map_err(|_| CredentialsError::CloudEnv)?;
         Self::from_str(cloud_str.as_str())
     }
 }
@@ -38,7 +39,7 @@ impl FromStr for FalconCloud {
             "us-2" => Ok(Self::Us2),
             "eu-1" => Ok(Self::Eu1),
             "us-gov-1" => Ok(Self::UsGov1),
-            _ => Err(CredentialsError(format!("Invalid FALCON_CLOUD specifier: '{s}'. Supported values are: us-1, us-2, eu-1, us-gov-1"))),
+            _ => Err(CredentialsError::Cloud(s.to_string())),
         }
     }
 }

src/easy/mod.rs

@@ -1,4 +1,3 @@
 //! Easy interfaces to get started!
 pub mod client;
 pub mod cloud;
-pub mod errors;

src/error.rs

@@ -0,0 +1,23 @@
+use crate::apis::oauth2_api::Oauth2AccessTokenError;
+
+#[derive(Debug, thiserror::Error)]
+pub enum CredentialsError {
+    #[error("Missing FALCON_CLIENT_ID environment variable. Please provide your OAuth2 API Client Secret for authentication with CrowdStrike Falcon platform. Establishing and retrieving OAuth2 API credentials can be performed at https://falcon.crowdstrike.com/support/api-clients-and-keys.")]
+    ClientID,
+    #[error("Missing FALCON_CLIENT_SECRET environment variable. Please provide your OAuth2 API Client Secret for authentication with CrowdStrike Falcon platform. Establishing and retrieving OAuth2 API credentials can be performed at https://falcon.crowdstrike.com/support/api-clients-and-keys.")]
+    Secret,
+    #[error(
+        "Invalid FALCON_CLOUD specifier: '{0}'. Supported values are: us-1, us-2, eu-1, us-gov-1"
+    )]
+    Cloud(String),
+    #[error("FALCON_CLOUD env variable is not set")]
+    CloudEnv,
+    #[error("Oauth error: {0}")]
+    Oauth(#[from] crate::apis::Error<Oauth2AccessTokenError>),
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("Credentials error: {0}")]
+    Credentials(#[from] CredentialsError),
+}

src/lib.rs

@@ -69,6 +69,7 @@ extern crate url;
 #[allow(clippy::all, clippy::pedantic)]
 pub mod apis;
 pub mod easy;
+pub mod error;
 // Disable lints in this module as it's autogenerated, we can run it manually if required
 #[allow(clippy::all, clippy::pedantic)]
 pub mod models;