Update 'memcache' to 0.17.

We no longer depend on 'r2d2-memcache', which was woefully out of date,
and instead implement our own r2d2 connection manager for memcache.

contrib/sync_db_pools/lib/Cargo.toml

@@ -19,7 +19,7 @@ diesel_postgres_pool = ["diesel/postgres", "diesel/r2d2"]
 diesel_mysql_pool = ["diesel/mysql", "diesel/r2d2"]
 sqlite_pool = ["rusqlite", "r2d2_sqlite"]
 postgres_pool = ["postgres", "r2d2_postgres"]
-memcache_pool = ["memcache", "r2d2-memcache"]
+memcache_pool = ["memcache"]
 
 [dependencies]
 r2d2 = "0.8"
@@ -34,8 +34,7 @@ r2d2_postgres = { version = "0.18", optional = true }
 rusqlite = { version = "0.31.0", optional = true }
 r2d2_sqlite = { version = "0.24.0", optional = true }
 
-memcache = { version = "0.15.2", optional = true }
-r2d2-memcache = { version = "0.6", optional = true }
+memcache = { version = "0.17.2", optional = true }
 
 [dependencies.rocket_sync_db_pools_codegen]
 version = "0.1.0"

contrib/sync_db_pools/lib/src/lib.rs

@@ -318,7 +318,7 @@
 //! | MySQL    | [Diesel]              | `2`       | [`diesel::MysqlConnection`]    | `diesel_mysql_pool`    |
 //! | Postgres | [Rust-Postgres]       | `0.19`    | [`postgres::Client`]           | `postgres_pool`        |
 //! | Sqlite   | [`Rusqlite`]          | `0.31`    | [`rusqlite::Connection`]       | `sqlite_pool`          |
-//! | Memcache | [`memcache`]          | `0.15`    | [`memcache::Client`]           | `memcache_pool`        |
+//! | Memcache | [`memcache`]          | `0.17`    | [`memcache::Client`]           | `memcache_pool`        |
 //!
 //! [Diesel]: https://diesel.rs
 //! [`diesel::SqliteConnection`]: https://docs.rs/diesel/2/diesel/sqlite/struct.SqliteConnection.html
@@ -327,10 +327,10 @@
 //! [Rust-Postgres]: https://github.com/sfackler/rust-postgres
 //! [`postgres::Client`]: https://docs.rs/postgres/0.19/postgres/struct.Client.html
 //! [`Rusqlite`]: https://github.com/jgallagher/rusqlite
-//! [`rusqlite::Connection`]: https://docs.rs/rusqlite/0.27/rusqlite/struct.Connection.html
+//! [`rusqlite::Connection`]: https://docs.rs/rusqlite/0.31/rusqlite/struct.Connection.html
 //! [`diesel::PgConnection`]: http://docs.diesel.rs/diesel/pg/struct.PgConnection.html
 //! [`memcache`]: https://github.com/aisk/rust-memcache
-//! [`memcache::Client`]: https://docs.rs/memcache/0.15/memcache/struct.Client.html
+//! [`memcache::Client`]: https://docs.rs/memcache/0.17/memcache/struct.Client.html
 //!
 //! The above table lists all the supported database adapters in this library.
 //! In order to use particular `Poolable` type that's included in this library,
@@ -372,7 +372,6 @@ pub use diesel;
 #[cfg(feature = "sqlite_pool")] pub use r2d2_sqlite;
 
 #[cfg(feature = "memcache_pool")] pub use memcache;
-#[cfg(feature = "memcache_pool")] pub use r2d2_memcache;
 
 pub use r2d2;
 

contrib/sync_db_pools/lib/src/poolable.rs

@@ -13,11 +13,12 @@ use crate::{Config, Error};
 ///
 /// Implementations of `Poolable` are provided for the following types:
 ///
-///   * `diesel::MysqlConnection`
-///   * `diesel::PgConnection`
-///   * `diesel::SqliteConnection`
-///   * `postgres::Connection`
-///   * `rusqlite::Connection`
+///   * [`diesel::MysqlConnection`](diesel::MysqlConnection)
+///   * [`diesel::PgConnection`](diesel::PgConnection)
+///   * [`diesel::SqliteConnection`](diesel::SqliteConnection)
+///   * [`postgres::Client`](postgres::Client)
+///   * [`rusqlite::Connection`](rusqlite::Connection)
+///   * [`memcache::Client`](memcache::Client)
 ///
 /// # Implementation Guide
 ///
@@ -263,19 +264,52 @@ impl Poolable for rusqlite::Connection {
 }
 
 #[cfg(feature = "memcache_pool")]
-impl Poolable for memcache::Client {
-    type Manager = r2d2_memcache::MemcacheConnectionManager;
-    // Unused, but we might want it in the future without a breaking change.
-    type Error = memcache::MemcacheError;
+mod memcache_pool {
+    use memcache::{Client, Connectable, MemcacheError};
 
-    fn pool(db_name: &str, rocket: &Rocket<Build>) -> PoolResult<Self> {
-        let config = Config::from(db_name, rocket)?;
-        let manager = r2d2_memcache::MemcacheConnectionManager::new(&*config.url);
-        let pool = r2d2::Pool::builder()
-            .max_size(config.pool_size)
-            .connection_timeout(Duration::from_secs(config.timeout as u64))
-            .build(manager)?;
+    use super::*;
 
-        Ok(pool)
+    #[derive(Debug)]
+    pub struct ConnectionManager {
+        urls: Vec<String>,
+    }
+
+    impl ConnectionManager {
+        pub fn new<C: Connectable>(target: C) -> Self {
+            Self { urls: target.get_urls(), }
+        }
+    }
+
+    impl r2d2::ManageConnection for ConnectionManager {
+        type Connection = Client;
+        type Error = MemcacheError;
+
+        fn connect(&self) -> Result<Client, MemcacheError> {
+            Client::connect(self.urls.clone())
+        }
+
+        fn is_valid(&self, connection: &mut Client) -> Result<(), MemcacheError> {
+            connection.version().map(|_| ())
+        }
+
+        fn has_broken(&self, _connection: &mut Client) -> bool {
+            false
+        }
+    }
+
+    impl super::Poolable for memcache::Client {
+        type Manager = ConnectionManager;
+        type Error = MemcacheError;
+
+        fn pool(db_name: &str, rocket: &Rocket<Build>) -> PoolResult<Self> {
+            let config = Config::from(db_name, rocket)?;
+            let manager = ConnectionManager::new(&*config.url);
+            let pool = r2d2::Pool::builder()
+                .max_size(config.pool_size)
+                .connection_timeout(Duration::from_secs(config.timeout as u64))
+                .build(manager)?;
+
+            Ok(pool)
+        }
     }
 }

contrib/sync_db_pools/lib/tests/databases.rs

@@ -11,6 +11,16 @@ mod databases_tests {
     struct PrimaryDb(diesel::PgConnection);
 }
 
+#[cfg(feature = "memcache_pool")]
+mod memcache_pool_tests {
+    #![allow(dead_code)]
+
+    use rocket_sync_db_pools::database;
+
+    #[database("test_db")]
+    struct MemcacheDb(memcache::Client);
+}
+
 #[cfg(test)]
 #[cfg(all(feature = "sqlite_pool"))]
 mod rusqlite_integration_test {