Final touches and bow-tieing on configuration. Update README to reflect.

1 files changed, 45 insertions, 26 deletions

diff --git a/src/config/mod.rs b/src/config/mod.rs
index 02ab941..983338c 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -28,9 +28,11 @@ use std::net::SocketAddr;
 use std::time::Duration;
 
 mod file;
+
 pub use self::file::FileConfig;
 
 mod environment;
+
 pub use self::environment::EnvironmentConfig;
 
 use Error;
@@ -44,26 +46,21 @@ pub const DEFAULT_STATUS_INTERVAL: Duration = Duration::from_secs(600);
 ///
 /// Specifies parameters needed to configure a Roughenough server.
 ///
-/// Parameters labeled "**Required**" must are always be provided and have no default value.
-/// Parameters labeled "**Optional**" provide default values that can be overridden.
-///
-/// * **`interface`** - [Required] IP address or interface name for listening to client requests
-/// * **`port`** - [Required] UDP port to listen for requests
-/// * **`seed`** - [Required] A 32-byte hexadecimal value used to generate the server's long-term
-///                key pair. **This is a secret value and must be un-guessable**,
-///                treat it with care.
-/// * **`batch_size`** - [Optional] The maximum number of requests to process in one batch. All
-///                      nonces in a batch are used to build a Merkle tree, the root of which
-///                      is signed.
-///                      Defaults to [DEFAULT_BATCH_SIZE](constant.DEFAULT_BATCH_SIZE.html)
-/// * **`status_interval`** - [Optional] Amount of time between each logged status update.
-///                           Defaults to [DEFAULT_STATUS_INTERVAL](constant.DEFAULT_STATUS_INTERVAL.html)
+/// Parameters labeled "**Required**" must always be provided and have no default value
+/// while those labeled "**Optional**" provide default values that can be overridden.
 ///
-/// Implementations of this trait obtain a valid configuration from different back-
-/// end sources.
+/// YAML Key | Environment Variable | Necessity | Description
+/// --- | --- | --- | ---
+/// `interface` | `ROUGHENOUGH_INTERFACE` | Required | IP address or interface name for listening to client requests
+/// `port` | `ROUGHENOUGH_PORT` | Required | UDP port to listen for requests
+/// `seed` | `ROUGHENOUGH_SEED` | Required | A 32-byte hexadecimal value used to generate the server's long-term key pair. **This is a secret value and must be un-guessable**, treat it with care.
+/// `batch_size` | `ROUGHENOUGH_BATCH_SIZE` | Optional | The maximum number of requests to process in one batch. All nonces in a batch are used to build a Merkle tree, the root of which is signed. Defaults to [DEFAULT_BATCH_SIZE](constant.DEFAULT_BATCH_SIZE.html) requests per batch.
+/// `status_interval` | `ROUGHENOUGH_STATUS_INTERVAL` | Optional | Number of _seconds_ between each logged status update. Default value is [DEFAULT_STATUS_INTERVAL](constant.DEFAULT_STATUS_INTERVAL.html).
 ///
-/// See:
-///   * [FileConfig](struct.FileConfig.html)
+/// Implementations of this trait obtain a valid configuration from different back-end
+/// sources. See:
+///   * [FileConfig](struct.FileConfig.html) - configure via a YAML file
+///   * [EnvironmentConfig](struct.EnvironmentConfig.html) - configure via environment vars
 ///
 pub trait ServerConfig {
     /// [Required] IP address or interface name to listen for client requests
@@ -90,6 +87,26 @@ pub trait ServerConfig {
     fn socket_addr(&self) -> Result<SocketAddr, Error>;
 }
 
+///
+/// Factory function to create a `ServerConfig` trait object based on the provided `arg`
+///
+pub fn make_config(arg: &str) -> Result<Box<ServerConfig>, Error> {
+    if arg == "ENV" {
+        match EnvironmentConfig::new() {
+            Ok(cfg) => Ok(Box::new(cfg)),
+            Err(e) => Err(e),
+        }
+    } else {
+        match FileConfig::new(arg) {
+            Ok(cfg) => Ok(Box::new(cfg)),
+            Err(e) => Err(e),
+        }
+    }
+}
+
+///
+/// Validate configuration settings
+///
 pub fn is_valid_config(cfg: &Box<ServerConfig>) -> bool {
     let mut is_valid = true;
 
@@ -101,13 +118,6 @@ pub fn is_valid_config(cfg: &Box<ServerConfig>) -> bool {
         error!("interface is missing");
         is_valid = false;
     }
-    match cfg.socket_addr() {
-        Err(e) => {
-            error!("{}:{}: {:?}", cfg.interface(), cfg.port(), e);
-            is_valid = false;
-        }
-        _ => ()
-    }
     if cfg.seed().is_empty() {
         error!("seed value is missing");
         is_valid = false;
@@ -121,6 +131,15 @@ pub fn is_valid_config(cfg: &Box<ServerConfig>) -> bool {
         is_valid = false;
     }
 
+    if is_valid {
+        match cfg.socket_addr() {
+            Err(e) => {
+                error!("failed to create socket {}:{} {:?}", cfg.interface(), cfg.port(), e);
+                is_valid = false;
+            }
+            _ => (),
+        }
+    }
+
     is_valid
 }
-