diff --git a/Cargo.lock b/Cargo.lock
index 27535bd..e98a49b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1075,6 +1075,7 @@ dependencies = [
  "dirs 2.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "indicatif 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "json 0.11.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "oss-rust-sdk 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "reqwest 0.9.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "rust-crypto 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/Cargo.toml b/Cargo.toml
index 9b21e6d..6ce03eb 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,6 +19,7 @@ sequoia-openpgp = "0.12.0"
 oss-rust-sdk = "0.1.12"
 chrono = "0.4.10"
 zip = "0.5.3"
+lazy_static = "1.3.0"
 rust_util = { git = "https://github.com/jht5945/rust_util" }
 
 
diff --git a/src/main.rs b/src/main.rs
index 9643f3f..ad05c40 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,5 @@
+#[macro_use]
+extern crate lazy_static;
 extern crate sequoia_openpgp as openpgp;
 pub mod oss_util;
 pub mod pgp_util;
@@ -71,15 +73,25 @@ fn main() -> XResult<()> {
 // TODO call it!
 pub fn process_oss_files(oss_client: &OSSClient, bucket_name: &str, path: &str, meta_file_name: &str, new_file: &str, limit: usize) -> XResult<()> {
     let meta_file_key = &format!("{}/{}", path, meta_file_name);
+    if *opt::IS_DEBUG {
+        print_message(MessageType::DEBUG, &format!("Read meta file: {}", meta_file_key));
+    }
     let meta_file_content = match oss_client.get_file_content(bucket_name, meta_file_key)? {
         None => "[]".to_string(),
         Some(c) => c,
     };
+    if *opt::IS_DEBUG {
+        print_message(MessageType::DEBUG, &format!("Read meta file content: {}", &meta_file_content));
+    }
     let (removed_file, new_meta_file_content) = process_new_backup_file(&meta_file_content, new_file, limit)?;
+    if *opt::IS_DEBUG {
+        print_message(MessageType::DEBUG, &format!("Processed meta file content: {}", &new_meta_file_content));
+    }
     oss_client.put_file_content(bucket_name, meta_file_key, &new_meta_file_content)?;
     if !removed_file.is_empty() {
         for rm_file in removed_file {
             let rm_file_key = &format!("{}/{}", path, rm_file);
+            print_message(MessageType::INFO, &format!("Remove OSS key: {}", rm_file_key));
             oss_client.delete_file(bucket_name, rm_file_key)?;
         }
     }
diff --git a/src/opt.rs b/src/opt.rs
index ee0ac83..f151df1 100644
--- a/src/opt.rs
+++ b/src/opt.rs
@@ -1,6 +1,13 @@
-use rust_util::XResult;
+use rust_util::{
+    XResult,
+    util_env::is_env_on,
+};
 use argparse::{ArgumentParser, StoreTrue, Store};
 
+lazy_static! {
+    pub static ref IS_DEBUG: bool = is_env_on("DEBUG");
+}
+
 pub struct Options {
     pub version: bool,
     pub verbose: bool,