Improve display of table config value.

lib/src/config/mod.rs

@@ -43,9 +43,9 @@
 //!   * **session_key**: _[string]_ a 256-bit base64 encoded string (44
 //!     characters) to use as the session key
 //!     * example: `"8Xui8SN4mI+7egV/9dlfYYLGQJeEx4+DwmSQLwDVXJg="`
-//!   * **tls**: _[dict]_ a dictionary with two keys: 1) `certs`: _[string]_ a
+//!   * **tls**: _[table]_ a table with two keys: 1) `certs`: _[string]_ a path
-//!     path to a certificate chain in PEM format, and 2) `key`: _[string]_ a
+//!   to a certificate chain in PEM format, and 2) `key`: _[string]_ a path to a
-//!     path to a private key file in PEM format for the certificate in `certs`
+//!   private key file in PEM format for the certificate in `certs`
 //!     * example: `{ certs = "/path/to/certs.pem", key = "/path/to/key.pem" }`
 //!
 //! ### Rocket.toml
@@ -196,6 +196,7 @@ pub use self::environment::Environment;
 pub use self::config::Config;
 pub use self::builder::ConfigBuilder;
 pub use self::toml_ext::IntoValue;
+pub(crate) use self::toml_ext::LoggedValue;
 
 use self::Environment::*;
 use self::environment::CONFIG_ENV;

lib/src/config/toml_ext.rs

@@ -1,3 +1,4 @@
+use std::fmt;
 use std::collections::{HashMap, BTreeMap};
 use std::hash::Hash;
 use std::str::FromStr;
@@ -133,6 +134,31 @@ impl_into_value!(Boolean: bool);
 impl_into_value!(Float: f64);
 impl_into_value!(Float: f32, as f64);
 
+/// A simple wrapper over a `Value` reference with a custom implementation of
+/// `Display`. This is used to log config values at initialization.
+pub(crate) struct LoggedValue<'a>(pub &'a Value);
+
+impl<'a> fmt::Display for LoggedValue<'a> {
+    #[inline]
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use config::Value::*;
+        match *self.0 {
+            String(_) | Integer(_) | Float(_) | Boolean(_) | Datetime(_) | Array(_) => {
+                self.0.fmt(f)
+            }
+            Table(ref map) => {
+                write!(f, "{{ ")?;
+                for (i, (key, val)) in map.iter().enumerate() {
+                    write!(f, "{} = {}", key, LoggedValue(val))?;
+                    if i != map.len() - 1 { write!(f, ", ")?; }
+                }
+
+                write!(f, " }}")
+            }
+        }
+    }
+}
+
 #[cfg(test)]
 mod test {
     use std::collections::BTreeMap;

lib/src/rocket.rs

@@ -11,7 +11,7 @@ use state::Container;
 #[cfg(feature = "tls")] use hyper_rustls::TlsServer;
 use {logger, handler};
 use ext::ReadExt;
-use config::{self, Config};
+use config::{self, Config, LoggedValue};
 use request::{Request, FormItems};
 use data::Data;
 use response::{Body, Response};
@@ -396,7 +396,8 @@ impl Rocket {
         }
 
         for (name, value) in config.extras() {
-            info_!("{} {}: {}", Yellow.paint("[extra]"), name, White.paint(value));
+            info_!("{} {}: {}",
+                   Yellow.paint("[extra]"), name, White.paint(LoggedValue(value)));
         }
 
         Rocket {