allow specifying db uri in config file

config/defaults.hjson

@@ -1,16 +1,37 @@
 {
   # settings related to the postgresql database
   database: {
-    # Username to connect to postgres
-    user: "lemmy"
-    # Password to connect to postgres
-    password: "password"
-    # Host where postgres is running
-    host: "localhost"
-    # Port where postgres can be accessed
-    port: 5432
-    # Name of the postgres database for lemmy
-    database: "lemmy"
+
+      # Configure the database by specifying a URI
+      # 
+      # This is the preferred method to specify database connection details since
+      # it is the most flexible.
+      # Connection URI pointing to a postgres instance
+      # 
+      # This example uses peer authentication to obviate the need for creating,
+      # configuring, and managing passwords.
+      # 
+      # For an explanation of how to use connection URIs, see [here][0] in
+      # PostgreSQL's documentation.
+      # 
+      # [0]: https://www.postgresql.org/docs/current/libpq-connect.html#id-1.7.3.8.3.6
+      uri: "postgresql:///lemmy?user=lemmy&host=/var/run/postgresql"
+      // or
+      # Configure the database by specifying parts of a URI
+      # 
+      # Note that specifying the `uri` field should be preferred since it provides
+      # greater control over how the connection is made. This merely exists for
+      # backwards-compatibility.
+      # Username to connect to postgres
+      user: "string"
+      # Password to connect to postgres
+      password: "string"
+      # Host where postgres is running
+      host: "string"
+      # Port where postgres can be accessed
+      port: 123
+      # Name of the postgres database for lemmy
+      database: "string"
     # Maximum number of active sql connections
     pool_size: 5
   }

crates/utils/src/settings/mod.rs

@@ -12,6 +12,8 @@ use std::{env, fs, io::Error};
 
 pub mod structs;
 
+use structs::DatabaseConnection;
+
 static DEFAULT_CONFIG_FILE: &str = "config/config.hjson";
 
 pub static SETTINGS: Lazy<Settings> = Lazy::new(|| {
@@ -43,15 +45,25 @@ impl Settings {
   }
 
   pub fn get_database_url(&self) -> String {
-    let conf = &self.database;
-    format!(
-      "postgres://{}:{}@{}:{}/{}",
-      utf8_percent_encode(&conf.user, NON_ALPHANUMERIC),
-      utf8_percent_encode(&conf.password, NON_ALPHANUMERIC),
-      conf.host,
-      conf.port,
-      utf8_percent_encode(&conf.database, NON_ALPHANUMERIC),
-    )
+    match &self.database.connection {
+      DatabaseConnection::Uri { uri } => uri.clone(),
+      DatabaseConnection::Parts {
+        user,
+        password,
+        host,
+        port,
+        database,
+      } => {
+        format!(
+          "postgres://{}:{}@{}:{}/{}",
+          utf8_percent_encode(user, NON_ALPHANUMERIC),
+          utf8_percent_encode(password, NON_ALPHANUMERIC),
+          host,
+          port,
+          utf8_percent_encode(database, NON_ALPHANUMERIC),
+        )
+      }
+    }
   }
 
   fn get_config_location() -> String {

crates/utils/src/settings/structs.rs

@@ -55,28 +55,62 @@ pub struct PictrsConfig {
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone, SmartDefault, Document)]
-#[serde(default, deny_unknown_fields)]
+#[serde(default)]
 pub struct DatabaseConfig {
-  /// Username to connect to postgres
-  #[default("lemmy")]
-  pub(super) user: String,
-  /// Password to connect to postgres
-  #[default("password")]
-  pub password: String,
-  #[default("localhost")]
-  /// Host where postgres is running
-  pub host: String,
-  /// Port where postgres can be accessed
-  #[default(5432)]
-  pub(super) port: i32,
-  /// Name of the postgres database for lemmy
-  #[default("lemmy")]
-  pub(super) database: String,
+  #[serde(flatten, default)]
+  pub connection: DatabaseConnection,
+
   /// Maximum number of active sql connections
   #[default(5)]
   pub pool_size: usize,
 }
 
+#[derive(Debug, Deserialize, Serialize, Clone, SmartDefault, Document)]
+#[serde(untagged)]
+pub enum DatabaseConnection {
+  /// Configure the database by specifying a URI
+  ///
+  /// This is the preferred method to specify database connection details since
+  /// it is the most flexible.
+  Uri {
+    /// Connection URI pointing to a postgres instance
+    ///
+    /// This example uses peer authentication to obviate the need for creating,
+    /// configuring, and managing passwords.
+    ///
+    /// For an explanation of how to use connection URIs, see [here][0] in
+    /// PostgreSQL's documentation.
+    ///
+    /// [0]: https://www.postgresql.org/docs/current/libpq-connect.html#id-1.7.3.8.3.6
+    #[doku(example = "postgresql:///lemmy?user=lemmy&host=/var/run/postgresql")]
+    uri: String,
+  },
+
+  /// Configure the database by specifying parts of a URI
+  ///
+  /// Note that specifying the `uri` field should be preferred since it provides
+  /// greater control over how the connection is made. This merely exists for
+  /// backwards-compatibility.
+  #[default]
+  Parts {
+    /// Username to connect to postgres
+    #[default("lemmy")]
+    user: String,
+    /// Password to connect to postgres
+    #[default("password")]
+    password: String,
+    #[default("localhost")]
+    /// Host where postgres is running
+    host: String,
+    /// Port where postgres can be accessed
+    #[default(5432)]
+    port: i32,
+    /// Name of the postgres database for lemmy
+    #[default("lemmy")]
+    database: String,
+  },
+}
+
 #[derive(Debug, Deserialize, Serialize, Clone, Document, SmartDefault)]
 #[serde(deny_unknown_fields)]
 pub struct EmailConfig {