Rewrite entire codebase to split into client and server

src/server/config.rs

@@ -0,0 +1,117 @@
+use std::{fs, path::PathBuf, time::Duration};
+
+use anyhow::{anyhow, Context};
+use clap::Parser;
+use serde::{Deserialize, Serialize};
+use sqlx::{mysql::MySqlConnectOptions, ConnectOptions, MySqlConnection};
+
+use crate::core::common::DEFAULT_CONFIG_PATH;
+
+pub const DEFAULT_PORT: u16 = 3306;
+pub const DEFAULT_TIMEOUT: u64 = 2;
+
+// NOTE: this might look empty now, and the extra wrapping for the mysql
+//       config seems unnecessary, but it will be useful later when we
+//       add more configuration options.
+#[derive(Debug, Clone, Deserialize, Serialize)]
+pub struct ServerConfig {
+    pub mysql: MysqlConfig,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize)]
+#[serde(rename = "mysql")]
+pub struct MysqlConfig {
+    pub host: String,
+    pub port: Option<u16>,
+    pub username: String,
+    pub password: String,
+    pub timeout: Option<u64>,
+}
+
+#[derive(Parser, Debug, Clone)]
+pub struct ServerConfigArgs {
+    /// Hostname of the MySQL server.
+    #[arg(long, value_name = "HOST", global = true)]
+    mysql_host: Option<String>,
+
+    /// Port of the MySQL server.
+    #[arg(long, value_name = "PORT", global = true)]
+    mysql_port: Option<u16>,
+
+    /// Username to use for the MySQL connection.
+    #[arg(long, value_name = "USER", global = true)]
+    mysql_user: Option<String>,
+
+    /// Path to a file containing the MySQL password.
+    #[arg(long, value_name = "PATH", global = true)]
+    mysql_password_file: Option<String>,
+
+    /// Seconds to wait for the MySQL connection to be established.
+    #[arg(long, value_name = "SECONDS", global = true)]
+    mysql_connect_timeout: Option<u64>,
+}
+
+/// Use the arguments and whichever configuration file which might or might not
+/// be found and default values to determine the configuration for the program.
+pub fn read_config_from_path_with_arg_overrides(
+    config_path: Option<PathBuf>,
+    args: ServerConfigArgs,
+) -> anyhow::Result<ServerConfig> {
+    let config = read_config_form_path(config_path)?;
+
+    let mysql = &config.mysql;
+
+    let password = if let Some(path) = args.mysql_password_file {
+        fs::read_to_string(path)
+            .context("Failed to read MySQL password file")
+            .map(|s| s.trim().to_owned())?
+    } else {
+        mysql.password.to_owned()
+    };
+
+    Ok(ServerConfig {
+        mysql: MysqlConfig {
+            host: args.mysql_host.unwrap_or(mysql.host.to_owned()),
+            port: args.mysql_port.or(mysql.port),
+            username: args.mysql_user.unwrap_or(mysql.username.to_owned()),
+            password,
+            timeout: args.mysql_connect_timeout.or(mysql.timeout),
+        },
+    })
+}
+
+pub fn read_config_form_path(config_path: Option<PathBuf>) -> anyhow::Result<ServerConfig> {
+    let config_path = config_path.unwrap_or_else(|| PathBuf::from(DEFAULT_CONFIG_PATH));
+
+    fs::read_to_string(&config_path)
+        .context(format!(
+            "Failed to read config file from {:?}",
+            &config_path
+        ))
+        .and_then(|c| toml::from_str(&c).context("Failed to parse config file"))
+        .context(format!(
+            "Failed to parse config file from {:?}",
+            &config_path
+        ))
+}
+
+/// Use the provided configuration to establish a connection to a MySQL server.
+pub async fn create_mysql_connection_from_config(
+    config: &MysqlConfig,
+) -> anyhow::Result<MySqlConnection> {
+    match tokio::time::timeout(
+        Duration::from_secs(config.timeout.unwrap_or(DEFAULT_TIMEOUT)),
+        MySqlConnectOptions::new()
+            .host(&config.host)
+            .username(&config.username)
+            .password(&config.password)
+            .port(config.port.unwrap_or(DEFAULT_PORT))
+            .database("mysql")
+            .connect(),
+    )
+    .await
+    {
+        Ok(connection) => connection.context("Failed to connect to MySQL"),
+        Err(_) => Err(anyhow!("Timed out after 2 seconds")).context("Failed to connect to MySQL"),
+    }
+}