Refactor config values merging (#24)

Additionally:
- fix config tests

config.toml

@@ -1,6 +1,26 @@
 [server]
+# IP address to bind HTTP server to.
+#
+# Default:
+#   bind_ip = "0.0.0.0"
+
+# Port to bind HTTP server to.
+#
+# Default:
+#   bind_port = 8080
+
+
+
+
+[rpc]
 # Duration, after which remote RPC client will be considered idle if no
 # heartbeat messages received.
 #
 # Default:
 #   idle_timeout = "10s"
+
+# Duration, after which the server deletes the client session if
+# the remote RPC client does not reconnect after it is idle.
+#
+# Default:
+#   reconnect_timeout = "10s"

src/conf/mod.rs

@@ -5,16 +5,11 @@ pub mod server;
 
 use std::env;
 
-use config::{
-    Config, ConfigError, Environment, File, FileFormat, Source, Value,
-};
+use config::{Config, Environment, File};
 use failure::Error;
 use serde::{Deserialize, Serialize};
 
-pub use self::rpc::Rpc;
-pub use self::server::Server;
-
-use std::collections::HashMap;
+pub use self::{rpc::Rpc, server::Server};
 
 /// CLI argument that is responsible for holding application configuration
 /// file path.
@@ -25,25 +20,13 @@ static APP_CONF_PATH_ENV_VAR_NAME: &str = "MEDEA_CONF";
 
 /// Holds application config.
 #[derive(Clone, Debug, Deserialize, Serialize, Default)]
+#[serde(default)]
 pub struct Conf {
-    /// HTTP server settings.
-    pub rpc: rpc::Rpc,
     /// RPC connection settings.
-    pub server: server::Server,
-}
-
-/// Allows merging [`Conf`] into [`config::Config`].
-// TODO: Remove after the following issue is resolved:
-//       https://github.com/mehcode/config-rs/issues/60#issuecomment-443241600
-impl Source for Conf {
-    fn clone_into_box(&self) -> Box<Source + Send + Sync> {
-        Box::new((*self).clone())
-    }
+    pub rpc: rpc::Rpc,
 
-    fn collect(&self) -> Result<HashMap<String, Value>, ConfigError> {
-        let serialized = toml::to_string(self).unwrap();
-        File::from_str(serialized.as_str(), FileFormat::Toml).collect()
-    }
+    /// HTTP server settings.
+    pub server: server::Server,
 }
 
 impl Conf {
@@ -54,19 +37,15 @@ impl Conf {
     ///   parameter or environment variable;
     /// - environment variables.
     pub fn parse() -> Result<Self, Error> {
-        // TODO: use Config::try_from(&Self::default()) when the issue is fixed:
-        //       https://github.com/mehcode/config-rs/issues/60
         let mut cfg = Config::new();
-        cfg.merge(Self::default())?;
 
         if let Some(path) = get_conf_file_name(env::args()) {
             cfg.merge(File::with_name(&path))?;
         }
 
         cfg.merge(Environment::with_prefix("MEDEA").separator("."))?;
 
-        let s: Self = cfg.try_into()?;
-        Ok(s)
+        Ok(cfg.try_into()?)
     }
 }
 
@@ -91,17 +70,22 @@ where
 }
 
 #[cfg(test)]
-mod get_conf_file_name_spec {
+mod tests {
+    use serial_test_derive::serial;
+    use std::{fs, time::Duration};
+
     use super::*;
 
     #[test]
-    fn none_if_nothing_is_set() {
+    #[serial]
+    fn get_conf_file_name_spec_none_if_nothing_is_set() {
         env::remove_var(APP_CONF_PATH_ENV_VAR_NAME);
         assert_eq!(get_conf_file_name(vec![]), None);
     }
 
     #[test]
-    fn none_if_empty() {
+    #[serial]
+    fn get_conf_file_name_spec_none_if_empty() {
         env::set_var(APP_CONF_PATH_ENV_VAR_NAME, "env_path");
         assert_eq!(
             get_conf_file_name(vec![
@@ -110,16 +94,20 @@ mod get_conf_file_name_spec {
             ]),
             None,
         );
+        env::remove_var(APP_CONF_PATH_ENV_VAR_NAME);
     }
 
     #[test]
-    fn env_if_set() {
+    #[serial]
+    fn get_conf_file_name_spec_env_if_set() {
         env::set_var(APP_CONF_PATH_ENV_VAR_NAME, "env_path");
         assert_eq!(get_conf_file_name(vec![]), Some("env_path".to_owned()));
+        env::remove_var(APP_CONF_PATH_ENV_VAR_NAME);
     }
 
     #[test]
-    fn arg_if_set() {
+    #[serial]
+    fn get_conf_file_name_spec_arg_if_set() {
         env::remove_var(APP_CONF_PATH_ENV_VAR_NAME);
         assert_eq!(
             get_conf_file_name(vec![
@@ -131,7 +119,8 @@ mod get_conf_file_name_spec {
     }
 
     #[test]
-    fn arg_is_prioritized() {
+    #[serial]
+    fn get_conf_file_name_spec_arg_is_prioritized() {
         env::set_var(APP_CONF_PATH_ENV_VAR_NAME, "env_path");
         assert_eq!(
             get_conf_file_name(vec![
@@ -140,20 +129,12 @@ mod get_conf_file_name_spec {
             ]),
             Some("arg_path".to_owned()),
         );
+        env::remove_var(APP_CONF_PATH_ENV_VAR_NAME);
     }
-}
-
-#[cfg(test)]
-mod conf_parse_spec {
-    use std::{fs, time::Duration};
-
-    use serial_test_derive::serial;
-
-    use super::*;
 
     #[test]
     #[serial]
-    fn file_overrides_defaults() {
+    fn conf_parse_spec_file_overrides_defaults() {
         let defaults = Conf::default();
         let test_config_file_path = "test_config.toml";
 
@@ -170,11 +151,9 @@ mod conf_parse_spec {
         assert_ne!(new_config.rpc.idle_timeout, defaults.rpc.idle_timeout);
     }
 
-    // TODO: This test seems to pollute environment and might
-    //       fail from time to time.
     #[test]
     #[serial]
-    fn env_overrides_defaults() {
+    fn conf_parse_spec_env_overrides_defaults() {
         let defaults = Conf::default();
 
         env::set_var("MEDEA_RPC.IDLE_TIMEOUT", "46s");
@@ -187,7 +166,7 @@ mod conf_parse_spec {
 
     #[test]
     #[serial]
-    fn env_overrides_file() {
+    fn conf_parse_spec_env_overrides_file() {
         let test_config_file_path = "test_config.toml";
 
         let data = format!("[rpc]\nidle_timeout = \"47s\"");

src/conf/rpc.rs

@@ -6,6 +6,7 @@ use std::time::Duration;
 
 /// RPC connection settings.
 #[derive(Clone, Debug, Deserialize, Serialize, SmartDefault)]
+#[serde(default)]
 pub struct Rpc {
     /// Duration, after which remote RPC client will be considered idle if no
     /// heartbeat messages received. Defaults to `10s`.

src/conf/server.rs

@@ -7,6 +7,7 @@ use smart_default::*;
 
 /// HTTP server settings.
 #[derive(Clone, Debug, Deserialize, Serialize, SmartDefault)]
+#[serde(default)]
 pub struct Server {
     /// IP address to bind HTTP server to. Defaults to `0.0.0.0`.
     #[default(IpAddr::V4(Ipv4Addr::new(0, 0, 0, 0)))]
@@ -48,6 +49,9 @@ mod server_spec {
 
         let env_conf = Conf::parse().unwrap();
 
+        env::remove_var("MEDEA_SERVER.BIND_IP");
+        env::remove_var("MEDEA_SERVER.BIND_PORT");
+
         assert_ne!(default_conf.server.bind_ip, env_conf.server.bind_ip);
         assert_ne!(default_conf.server.bind_port, env_conf.server.bind_port);