Parse command-line-arguments

Use command-line-arguments to set the config file path and the log
level.

src/args.rs

@@ -0,0 +1,15 @@
+use clap::Parser;
+use std::path::PathBuf;
+use tracing::Level;
+
+#[derive(Parser)]
+#[command(author, version, about)]
+pub struct Args {
+    /// Use a custom config file
+    #[arg(short, long, value_name = "FILE")]
+    config: Option<PathBuf>,
+
+    /// Set a log level
+    #[arg(short, long, value_name = "LEVEL", default_value_t = Level::INFO)]
+    pub log_level: Level,
+}

src/main.rs

@@ -1,4 +1,5 @@
 use anyhow::Result;
+use clap::Parser;
 use diesel::{
     prelude::*,
     r2d2::{ConnectionManager, Pool, PooledConnection},
@@ -8,10 +9,12 @@ use std::{env, thread::park_timeout};
 use time::{Duration, OffsetDateTime};
 use tracing::{debug, info, trace};
 
+mod args;
 mod config;
 mod models;
 mod schema;
 
+use args::Args;
 use config::Config;
 use models::{NewReminder, Reminder};
 
@@ -54,6 +57,12 @@ fn remind(
 }
 
 fn main() -> Result<()> {
+    let args = Args::parse();
+
+    if env::var("RUST_LOG").is_err() {
+        env::set_var("RUST_LOG", format!("{}", args.log_level));
+    }
+
     tracing_subscriber::fmt::init();
 
     info!(