Add verbose flag

src/check.rs

@@ -128,7 +128,7 @@ where
     let mut command = Command::new("nix");
     command.args(args_vec);
 
-    log::debug!("run command: {:?}", command_vec);
+    log::trace!("run command: {:?}", command_vec);
 
     let output = get_command_output(command)?;
 
@@ -138,7 +138,7 @@ where
         stdout: String::from_utf8(output.stdout)?,
         stderr: String::from_utf8(output.stderr)?,
     };
-    log::debug!("command called:\n{}", process_info);
+    log::trace!("command called:\n{}", process_info);
     if !output.status.success() {
         return Err(Error::ProcessFailed(process_info));
     }

src/main.rs

@@ -9,9 +9,8 @@ use error::Error;
 use options::{Commands, Options};
 
 fn main() {
-    init_logger();
-
     let options = options::Options::parse();
+    init_logger(&options);
     log::debug!("options = {:#?}", options);
     if let Err(e) = main_result(options) {
         log::error!("{}", e);
@@ -27,11 +26,16 @@ fn main_result(options: Options) -> Result<(), Error> {
     Ok(())
 }
 
-fn init_logger() {
+fn init_logger(options: &Options) {
     let mut builder = pretty_env_logger::formatted_builder();
+    let default_level = match options.verbose {
+        0 => "info",
+        1 => "debug",
+        _ => "trace",
+    };
     let filters = match std::env::var("RUST_LOG") {
         Ok(f) => f,
-        Err(_) => "flat_flake=info".to_string(),
+        Err(_) => format!("flat_flake={default_level}"),
     };
     builder.parse_filters(&filters);
     builder.init()

src/options.rs

@@ -7,6 +7,9 @@ use clap::{Parser, Subcommand};
 pub struct Options {
     #[command(subcommand)]
     pub command: Commands,
+    #[arg(short, long, global = true, action = clap::ArgAction::Count,
+          help = "Increase logging verbosity, override by RUST_LOG")]
+    pub verbose: u8,
 }
 
 #[derive(Clone, Debug, Subcommand)]