show existing domain info on get page

src/service.rs

@@ -179,19 +179,22 @@ impl<'svc> Service<'svc> {
             config: Option<domain::config::Config>,
         }
 
-        match self.domain_manager.get_config(&args.domain) {
-            Ok(_config) => self.render_error_page(500, "TODO not yet implemented"),
-            Err(domain::manager::GetConfigError::NotFound) => self.render_page(
+        let config = match self.domain_manager.get_config(&args.domain) {
+            Ok(config) => Some(config),
+            Err(domain::manager::GetConfigError::NotFound) => None,
+            Err(domain::manager::GetConfigError::Unexpected(e)) => {
+                return self
+                    .render_error_page(500, format!("retrieving configuration: {}", e).as_str());
+            }
+        };
+
+        self.render_page(
             "/domain.html",
             &Response {
                 domain: args.domain,
-                    config: None,
+                config: config,
             },
-            ),
-            Err(domain::manager::GetConfigError::Unexpected(e)) => {
-                self.render_error_page(500, format!("retrieving configuration: {}", e).as_str())
-            }
-        }
+        )
     }
 
     fn domain_init(&self, args: DomainInitArgs, domain_config: util::FlatConfig) -> SvcResponse {

src/service/http_tpl/domain.html

@@ -2,11 +2,21 @@
   Configure New Domain
 </h2>
 
+{{# if data.config }}
+
+<p>Your domain <code>{{ data.domain }}</code> is already configured with
+Domiply. You can see the existing configuration below. If you modify any values
+you will need to hit the "Next" button to complete the update.</p>
+
+{{ else }}
+
 <p>Your domain <code>{{ data.domain }}</code> is not yet configured with Domiply.
 To get started, please input the details of a public git repo which will be used
 to serve your domain. When you update the given branch, your domain will be
 automatically updated too!</p>
 
+{{/if}}
+
 <p><em>In the future Domiply will support more backends than just git
   repos.</em></p>