From ee92301fb960146700ef7d483d0f632888480f46 Mon Sep 17 00:00:00 2001
From: Vincent Breitmoser <look@my.amazin.horse>
Date: Sun, 5 May 2019 20:17:54 +0200
Subject: [PATCH] add "maintenance mode"

---
 Rocket.toml.dist                    |  3 ++
 dist/templates/maintenance.html.hbs |  8 ++++
 src/web/maintenance.rs              | 68 +++++++++++++++++++++++++++++
 src/web/mod.rs                      | 13 ++++++
 4 files changed, 92 insertions(+)
 create mode 100644 dist/templates/maintenance.html.hbs
 create mode 100644 src/web/maintenance.rs

diff --git a/Rocket.toml.dist b/Rocket.toml.dist
index d861279..a0e2c91 100644
--- a/Rocket.toml.dist
+++ b/Rocket.toml.dist
@@ -15,6 +15,7 @@ keys_external_dir = "state/keys-external"
 token_dir = "state/tokens"
 tmp_dir = "state/tmp"
 mail_rate_limit = 60
+maintenance_file = "state/maintenance"
 
 [staging]
 base-URI = "https://keys.openpgp.org"
@@ -29,6 +30,7 @@ assets_dir = "public/assets"
 token_dir = "tokens"
 tmp_dir = "tmp"
 mail_rate_limit = 60
+maintenance_file = "maintenance"
 
 [production]
 base-URI = "https://keys.openpgp.org"
@@ -43,3 +45,4 @@ assets_dir = "public/assets"
 token_dir = "tokens"
 tmp_dir = "tmp"
 mail_rate_limit = 3600
+maintenance_file = "maintenance"
diff --git a/dist/templates/maintenance.html.hbs b/dist/templates/maintenance.html.hbs
new file mode 100644
index 0000000..1e7d895
--- /dev/null
+++ b/dist/templates/maintenance.html.hbs
@@ -0,0 +1,8 @@
+{{#> layout }}
+  <h2>Maintenance Mode</h2>
+
+  <p>
+  {{message}}
+  </p>
+
+{{/layout}}
diff --git a/src/web/maintenance.rs b/src/web/maintenance.rs
new file mode 100644
index 0000000..1c1a16e
--- /dev/null
+++ b/src/web/maintenance.rs
@@ -0,0 +1,68 @@
+use rocket::{Request, Data};
+use rocket::fairing::{Fairing, Info, Kind};
+use rocket_contrib::templates::Template;
+use rocket::http::Method;
+
+use std::fs;
+use std::path::PathBuf;
+
+use web::MyResponse;
+
+pub struct MaintenanceMode {
+    maintenance_file: PathBuf,
+}
+
+mod templates {
+    #[derive(Serialize)]
+    pub struct MaintenanceMode {
+        pub message: String,
+        pub commit: String,
+        pub version: String,
+    }
+}
+
+impl Fairing for MaintenanceMode {
+    fn info(&self) -> Info {
+        Info {
+            name: "Maintenance Mode",
+            kind: Kind::Request
+        }
+    }
+
+    fn on_request(&self, request: &mut Request, _: &Data) {
+        if !self.is_relevant_path(request.uri().path()) { 
+            return;
+        }
+        if let Some(message) = self.get_maintenance_message() {
+            request.set_uri(uri!(maintenance_error: message));
+            request.set_method(Method::Get);
+        }
+    }
+}
+
+impl MaintenanceMode {
+    pub fn new(maintenance_file: PathBuf) -> Self {
+        MaintenanceMode { maintenance_file }
+    }
+
+    fn is_relevant_path(&self, path: &str) -> bool {
+        path.starts_with("/publish") || path.starts_with("/manage")
+    }
+
+    fn get_maintenance_message(&self) -> Option<String> {
+        if !self.maintenance_file.exists() {
+            return None;
+        }
+        fs::read_to_string(&self.maintenance_file).ok()
+    }
+}
+
+#[get("/maintenance/<message>")]
+pub fn maintenance_error(message: String) -> MyResponse {
+    let ctx = templates::MaintenanceMode{
+        message,
+        version: env!("VERGEN_SEMVER").to_string(),
+        commit: env!("VERGEN_SHA_SHORT").to_string(),
+    };
+    MyResponse::ServerError(Template::render("maintenance", ctx))
+}
diff --git a/src/web/mod.rs b/src/web/mod.rs
index d86b784..5d342cd 100644
--- a/src/web/mod.rs
+++ b/src/web/mod.rs
@@ -24,6 +24,9 @@ use std::convert::TryInto;
 
 mod hkp;
 mod manage;
+mod maintenance;
+
+use web::maintenance::MaintenanceMode;
 
 use rocket::http::hyper::header::ContentDisposition;
 
@@ -338,6 +341,8 @@ fn rocket_factory(rocket: rocket::Rocket) -> Result<rocket::Rocket> {
         manage::vks_manage_key,
         manage::vks_manage_post,
         manage::vks_manage_unpublish,
+        // Maintenance error page
+        maintenance::maintenance_error,
     ];
 
     let db_service = configure_db_service(rocket.config())?;
@@ -346,9 +351,11 @@ fn rocket_factory(rocket: rocket::Rocket) -> Result<rocket::Rocket> {
     let stateless_token_service = configure_stateless_token_service(rocket.config())?;
     let mail_service = configure_mail_service(rocket.config())?;
     let rate_limiter = configure_rate_limiter(rocket.config())?;
+    let maintenance_mode = configure_maintenance_mode(rocket.config())?;
 
     Ok(rocket
        .attach(Template::fairing())
+       .attach(maintenance_mode)
        .manage(hagrid_state)
        .manage(stateless_token_service)
        .manage(stateful_token_service)
@@ -431,6 +438,12 @@ fn configure_rate_limiter(config: &Config) -> Result<RateLimiter> {
     Ok(RateLimiter::new(timeout_secs))
 }
 
+fn configure_maintenance_mode(config: &Config) -> Result<MaintenanceMode> {
+    let maintenance_file: PathBuf = config.get_str("maintenance_file")
+        .unwrap_or("maintenance").into();
+    Ok(MaintenanceMode::new(maintenance_file))
+}
+
 #[cfg(test)]
 pub mod tests {
     use regex;