feat(postgres): add an option to specify extra options (#1539)

* feat(postgres): add an option to specify extra options ...

... this allow you to specify stuff like search path and statement
timeouts etc.

* feat(postgres): set options through setting run-time parameters

* feat(postgres): use flat command-list instead of hashmap

* feat(postgres): make the options taking parameters with `Display` trait

Author: liushuyu

sqlx-core/src/postgres/connection/establish.rs

@@ -40,6 +40,10 @@ impl PgConnection {
             params.push(("application_name", application_name));
         }
 
+        if let Some(ref options) = options.options {
+            params.push(("options", options));
+        }
+
         stream
             .send(Startup {
                 username: Some(&options.username),

sqlx-core/src/postgres/options/mod.rs

@@ -1,4 +1,5 @@
 use std::env::var;
+use std::fmt::Display;
 use std::path::{Path, PathBuf};
 
 mod connect;
@@ -33,6 +34,7 @@ pub use ssl_mode::PgSslMode;
 /// | `password` | `None` | Password to be used if the server demands password authentication. |
 /// | `port` | `5432` | Port number to connect to at the server host, or socket file name extension for Unix-domain connections. |
 /// | `dbname` | `None` | The database name. |
+/// | `options` | `None` | The runtime parameters to send to the server at connection start. |
 ///
 /// The URI scheme designator can be either `postgresql://` or `postgres://`.
 /// Each of the URI parts is optional.
@@ -85,6 +87,7 @@ pub struct PgConnectOptions {
     pub(crate) statement_cache_capacity: usize,
     pub(crate) application_name: Option<String>,
     pub(crate) log_settings: LogSettings,
+    pub(crate) options: Option<String>,
 }
 
 impl Default for PgConnectOptions {
@@ -145,6 +148,7 @@ impl PgConnectOptions {
             statement_cache_capacity: 100,
             application_name: var("PGAPPNAME").ok(),
             log_settings: Default::default(),
+            options: var("PGOPTIONS").ok(),
         }
     }
 
@@ -332,6 +336,34 @@ impl PgConnectOptions {
         self
     }
 
+    /// Set additional startup options for the connection as a list of key-value pairs.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// # use sqlx_core::postgres::PgConnectOptions;
+    /// let options = PgConnectOptions::new()
+    ///     .options([("geqo", "off"), ("statement_timeout", "5min")]);
+    /// ```
+    pub fn options<K, V, I>(mut self, options: I) -> Self
+    where
+        K: Display,
+        V: Display,
+        I: IntoIterator<Item = (K, V)>,
+    {
+        let mut options_str = String::new();
+        for (k, v) in options {
+            options_str += &format!("-c {}={}", k, v);
+        }
+        if let Some(ref mut v) = self.options {
+            v.push(' ');
+            v.push_str(&options_str);
+        } else {
+            self.options = Some(options_str);
+        }
+        self
+    }
+
     /// We try using a socket if hostname starts with `/` or if socket parameter
     /// is specified.
     pub(crate) fn fetch_socket(&self) -> Option<String> {

sqlx-core/src/postgres/options/parse.rs

@@ -85,6 +85,21 @@ impl FromStr for PgConnectOptions {
 
                 "application_name" => options = options.application_name(&*value),
 
+                "options" => {
+                    if let Some(options) = options.options.as_mut() {
+                        options.push(' ');
+                        options.push_str(&*value);
+                    } else {
+                        options.options = Some(value.to_string());
+                    }
+                }
+
+                k if k.starts_with("options[") => {
+                    if let Some(key) = k.strip_prefix("options[").unwrap().strip_suffix(']') {
+                        options = options.options([(key, &*value)]);
+                    }
+                }
+
                 _ => log::warn!("ignoring unrecognized connect parameter: {}={}", key, value),
             }
         }
@@ -197,3 +212,23 @@ fn it_parses_socket_correctly_with_username_percent_encoded() {
     assert_eq!(Some("/var/lib/postgres/".into()), opts.socket);
     assert_eq!(Some("database"), opts.database.as_deref());
 }
+#[test]
+fn it_parses_libpq_options_correctly() {
+    let uri = "postgres:///?options=-c%20synchronous_commit%3Doff%20--search_path%3Dpostgres";
+    let opts = PgConnectOptions::from_str(uri).unwrap();
+
+    assert_eq!(
+        Some("-c synchronous_commit=off --search_path=postgres".into()),
+        opts.options
+    );
+}
+#[test]
+fn it_parses_sqlx_options_correctly() {
+    let uri = "postgres:///?options[synchronous_commit]=off&options[search_path]=postgres";
+    let opts = PgConnectOptions::from_str(uri).unwrap();
+
+    assert_eq!(
+        Some("-c synchronous_commit=off -c search_path=postgres".into()),
+        opts.options
+    );
+}