Add -v option to print out logs (>= info) (#164)

src/config.rs

@@ -117,6 +117,10 @@ pub struct CommandLineArgs {
     /// Do not perform upgrades for the given steps
     #[structopt(long = "disable", raw(possible_values = "&Step::possible_values()"))]
     disable: Vec<Step>,
+
+    /// Output logs
+    #[structopt(short = "v", long = "verbose")]
+    verbose: bool,
 }
 
 /// Represents the application configuration
@@ -189,4 +193,9 @@ impl Config {
     pub fn no_retry(&self) -> bool {
         self.opt.no_retry
     }
+
+    /// Tell whether we should print log.
+    pub fn verbose(&self) -> bool {
+        self.opt.verbose
+    }
 }

src/main.rs

@@ -1,3 +1,5 @@
+#![allow(clippy::cognitive_complexity)]
+
 mod config;
 mod ctrlc;
 mod error;
@@ -14,6 +16,7 @@ use self::error::{Error, ErrorKind};
 use self::report::Report;
 use self::steps::*;
 use self::terminal::*;
+use env_logger::Env;
 use failure::{Fail, ResultExt};
 use log::debug;
 #[cfg(feature = "self-update")]
@@ -73,7 +76,11 @@ fn run() -> Result<(), Error> {
         }
     }
 
-    env_logger::init();
+    let mut env = Env::default();
+    if config.verbose() {
+        env = env.filter_or("LOG_LEVEL", "info");
+    }
+    env_logger::init_from_env(env);
 
     let git = git::Git::new();
     let mut git_repos = git::Repositories::new(&git);