wg show <interface> if specified in the command line (#17)

Using `interface` instead of `all` if specified

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name                     = "prometheus_wireguard_exporter"
-version                  = "3.1.1"
+version                  = "3.2.0"
 authors                  = ["Francesco Cogno <francesco.cogno@outlook.com>"]
 description              = "Prometheus WireGuard Exporter"
 edition                  = "2018"

README.md

@@ -4,15 +4,15 @@
 
 [![Crate](https://img.shields.io/crates/v/prometheus_wireguard_exporter.svg)](https://crates.io/crates/prometheus_wireguard_exporter) [![cratedown](https://img.shields.io/crates/d/prometheus_wireguard_exporter.svg)](https://crates.io/crates/prometheus_wireguard_exporter) [![cratelastdown](https://img.shields.io/crates/dv/prometheus_wireguard_exporter.svg)](https://crates.io/crates/prometheus_wireguard_exporter)
 
-[![release](https://img.shields.io/github/release/MindFlavor/prometheus_wireguard_exporter.svg)](https://github.com/MindFlavor/prometheus_wireguard_exporter/tree/3.1.1)
+[![release](https://img.shields.io/github/release/MindFlavor/prometheus_wireguard_exporter.svg)](https://github.com/MindFlavor/prometheus_wireguard_exporter/tree/3.2.0)
-[![tag](https://img.shields.io/github/tag/mindflavor/prometheus_wireguard_exporter.svg)](https://github.com/MindFlavor/prometheus_wireguard_exporter/tree/3.1.1)
+[![tag](https://img.shields.io/github/tag/mindflavor/prometheus_wireguard_exporter.svg)](https://github.com/MindFlavor/prometheus_wireguard_exporter/tree/3.2.0)
 
 [![Build Status](https://travis-ci.org/MindFlavor/prometheus_wireguard_exporter.svg?branch=master)](https://travis-ci.org/MindFlavor/prometheus_wireguard_exporter)
-[![commitssince](https://img.shields.io/github/commits-since/mindflavor/prometheus_wireguard_exporter/3.1.1.svg)](https://img.shields.io/github/commits-since/mindflavor/prometheus_wireguard_exporter/3.1.1.svg)
+[![commitssince](https://img.shields.io/github/commits-since/mindflavor/prometheus_wireguard_exporter/3.2.0.svg)](https://img.shields.io/github/commits-since/mindflavor/prometheus_wireguard_exporter/3.2.0.svg)
 
 ## Intro
 
-A Prometheus exporter for [WireGuard](https://www.wireguard.com), written in Rust. This tool exports the `wg show all dump` results in a format that [Prometheus](https://prometheus.io/) can understand. The exporter is very light on your server resources, both in terms of memory and CPU usage.
+A Prometheus exporter for [WireGuard](https://www.wireguard.com), written in Rust. This tool exports the `wg show all dump` (or `wg show <interface> dump` if you specify a config file) results in a format that [Prometheus](https://prometheus.io/) can understand. The exporter is very light on your server resources, both in terms of memory and CPU usage.
 
 Starting from release [2.0.2](https://github.com/MindFlavor/prometheus_wireguard_exporter/releases/tag/2.0.2) this exporter supports IPv6 addressess too (thanks to [Maximilian Bosch](https://github.com/Ma27)'s PR [#5](https://github.com/MindFlavor/prometheus_wireguard_exporter/pull/5)).
 From release [3.0.0](https://github.com/MindFlavor/prometheus_wireguard_exporter/releases/tag/3.0.0) the exporter allows two label modes: one is to dump every allowed ip in a single label (called `allowed_ips`) along with their subnets. The second one is to create a pair of labels for each allowed ip/subnet pair (called `allowed_ip_0`/`allowed_subnet_0`, `allowed_ip_1`/`allowed_subnet_1` and so on for every allowed ip). The default if the single label mode but you can enable the second mode by specifying the `-s` switch at startup. Thank you [Toon Schoenmakers](https://github.com/schoentoon) for this solution (see [https://github.com/MindFlavor/prometheus_wireguard_exporter/issues/8](https://github.com/MindFlavor/prometheus_wireguard_exporter/issues/8)).

src/main.rs

@@ -5,7 +5,7 @@ use clap;
 use clap::{crate_authors, crate_name, crate_version, Arg};
 use futures::future::{done, ok, Either, Future};
 use hyper::{Body, Request, Response};
-use log::{info, trace};
+use log::{debug, info, trace};
 use std::env;
 mod options;
 use options::Options;
@@ -25,14 +25,13 @@ use std::sync::Arc;
 
 fn wg_with_text(
     wg_config_str: &str,
-    wg_output: ::std::process::Output,
+    wg_output_str: &str,
     options: Arc<Options>,
 ) -> Result<Response<Body>, ExporterError> {
     let pehm = peer_entry_hashmap_try_from(wg_config_str)?;
     trace!("pehm == {:?}", pehm);
 
-    let wg_output_string = String::from_utf8(wg_output.stdout)?;
+    let wg = WireGuard::try_from(wg_output_str)?;
-    let wg = WireGuard::try_from(&wg_output_string as &str)?;
     Ok(Response::new(Body::from(wg.render_with_names(
         Some(&pehm),
         options.separate_allowed_ips,
@@ -45,30 +44,60 @@ fn perform_request(
     options: &Arc<Options>,
 ) -> impl Future<Item = Response<Body>, Error = failure::Error> {
     trace!("perform_request");
-
     // this is needed to satisfy the borrow checker
     let options = options.clone();
+    debug!("options == {:?}", options);
+
+    //let interface = options.get_interface();
+
+    let interface_str = match options.get_interface() {
+        Some(interface_str) => interface_str,
+        None => "all",
+    }
+    .to_owned();
+
+    debug!("using inteface_str {}", interface_str);
 
     done(
         Command::new("wg")
             .arg("show")
-            .arg("all")
+            .arg(&interface_str)
             .arg("dump")
             .output(),
     )
     .from_err()
     .and_then(move |output| {
+        done(String::from_utf8(output.stdout))
+            .from_err()
+            .and_then(move |output_str| {
+                trace!("wg show output == {}", output_str);
+
+                // the output of wg show is different if we use all or we specify an interface.
+                // In the first case the first column will be the interface name. In the second case
+                // the interface name will be omitted. We need to compensate for the skew somehow (one
+                // column less in the second case). We solve this prepending the interface name in every
+                // line so the output of the second case will be equal to the first case.
+                let output_str = if interface_str != "all" {
+                    debug!("injecting {} to the wg show output", interface_str);
+                    let mut result = String::new();
+                    for s in output_str.lines() {
+                        result.push_str(&format!("{}\t{}\n", interface_str, s));
+                    }
+                    result
+                } else {
+                    output_str
+                };
+
                 if let Some(extract_names_config_file) = &options.extract_names_config_file {
                     Either::A(
                         done(::std::fs::read_to_string(extract_names_config_file))
                             .from_err()
-                    .and_then(|wg_config_string| {
+                            .and_then(move |wg_config_string| {
-                        wg_with_text(&wg_config_string as &str, output, options)
+                                wg_with_text(&wg_config_string as &str, &output_str, options)
                             }),
                     )
                 } else {
-            Either::B(done(String::from_utf8(output.stdout)).from_err().and_then(
+                    Either::B({
-                move |output_str| {
                         trace!("{}", output_str);
                         done(WireGuard::try_from(&output_str as &str))
                             .from_err()
@@ -79,11 +108,11 @@ fn perform_request(
                                     options.export_remote_ip_and_port,
                                 ))))
                             })
-                },
+                    })
-            ))
                 }
             })
             .from_err()
+    })
 }
 
 fn main() {

src/options.rs

@@ -24,4 +24,46 @@ impl Options {
             }
         }
     }
+
+    pub fn get_interface(&self) -> Option<&str> {
+        if let Some(config_file) = &self.extract_names_config_file {
+            let path = std::path::Path::new(config_file);
+            if let Some(file_stem) = path.file_stem() {
+                file_stem.to_str()
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_interface_some() {
+        let options = Options {
+            verbose: true,
+            separate_allowed_ips: false,
+            extract_names_config_file: Some("/etc/wireguard/wg0.conf".to_owned()),
+            export_remote_ip_and_port: true,
+        };
+
+        assert_eq!(options.get_interface(), Some("wg0"));
+    }
+
+    #[test]
+    fn test_interface_none() {
+        let options = Options {
+            verbose: true,
+            separate_allowed_ips: false,
+            extract_names_config_file: None,
+            export_remote_ip_and_port: true,
+        };
+
+        assert_eq!(options.get_interface(), None);
+    }
 }