api: introduce feature error-backtrace

Intoduce feature `error-backtrace` to reduce dependency of the
nydus-service crate.

Signed-off-by: Jiang Liu <gerry@linux.alibaba.com>

Cargo.toml

@@ -56,7 +56,7 @@ openssl = { version = "0.10.48", features = ["vendored"] }
 # pin openssl-src to bring in fix for https://rustsec.org/advisories/RUSTSEC-2022-0032
 #openssl-src = { version = "111.22" }
 
-nydus-api = { version = "0.3.0", path = "api", features = ["handler"] }
+nydus-api = { version = "0.3.0", path = "api", features = ["error-backtrace", "handler"] }
 nydus-builder = { version = "0.1.0", path = "builder" }
 nydus-rafs = { version = "0.3.1", path = "rafs" }
 nydus-service = { version = "0.3.0", path = "service", features = ["block-device"] }

api/Cargo.toml

@@ -9,20 +9,22 @@ repository = "https://github.com/dragonflyoss/image-service"
 edition = "2018"
 
 [dependencies]
-backtrace = "0.3"
+libc = "0.2"
+log = "0.4.8"
+serde_json = "1.0.53"
+toml = "0.5"
+
+backtrace = { version = "0.3", optional = true }
 dbs-uhttp = { version = "0.3.0", optional = true }
 http = { version = "0.2.1", optional = true }
 lazy_static = { version = "1.4.0", optional = true }
-libc = "0.2"
-log = "0.4.8"
 mio = { version = "0.8", features = ["os-poll", "os-ext"], optional = true }
 serde = { version = "1.0.110", features = ["rc", "serde_derive"] }
-serde_json = "1.0.53"
-toml = "0.5"
 url = { version = "2.1.1", optional = true }
 
 [dev-dependencies]
 vmm-sys-util = { version = "0.10" }
 
 [features]
 handler = ["dbs-uhttp", "http", "lazy_static", "mio", "url"]
+error-backtrace = ["backtrace"]

api/src/error.rs

@@ -2,26 +2,29 @@
 //
 // SPDX-License-Identifier: Apache-2.0
 
-use std::env;
 use std::fmt::Debug;
 
-use log::error;
-
 /// Display error messages with line number, file path and optional backtrace.
-pub fn make_error(err: std::io::Error, raw: impl Debug, file: &str, line: u32) -> std::io::Error {
-    if cfg!(debug_assertions) {
-        if let Ok(val) = env::var("RUST_BACKTRACE") {
+pub fn make_error(
+    err: std::io::Error,
+    _raw: impl Debug,
+    _file: &str,
+    _line: u32,
+) -> std::io::Error {
+    #[cfg(all(debug_assertions, feature = "error-backtrace"))]
+    {
+        if let Ok(val) = std::env::var("RUST_BACKTRACE") {
             if val.trim() != "0" {
-                error!("Stack:\n{:?}", backtrace::Backtrace::new());
-                error!("Error:\n\t{:?}\n\tat {}:{}", raw, file, line);
+                log::error!("Stack:\n{:?}", backtrace::Backtrace::new());
+                log::error!("Error:\n\t{:?}\n\tat {}:{}", _raw, _file, _line);
                 return err;
             }
         }
+        log::error!(
+            "Error:\n\t{:?}\n\tat {}:{}\n\tnote: enable `RUST_BACKTRACE=1` env to display a backtrace",
+            _raw, _file, _line
+        );
     }
-    error!(
-        "Error:\n\t{:?}\n\tat {}:{}\n\tnote: enable `RUST_BACKTRACE=1` env to display a backtrace",
-        raw, file, line
-    );
     err
 }