feat: add PING_EXPORTER_RESOLVER option

CHANGELOG.md

@@ -1,6 +1,11 @@
 # Change Log
 All notable changes to this project will be documented in this file.
 
+## 0.3.0 - 2019-08-12
+
+- Add `PING_EXPORTER_RESOLVER` option
+
+
 ## 0.2.0 - 2018-11-12
 
 - Add `ping_resolve_error` metric

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ping-exporter"
-version = "0.2.0"
+version = "0.3.0"
 authors = ["Fedor Gogolev <[email protected]>"]
 publish = false
 

README.md

@@ -21,6 +21,7 @@ Visiting [http://localhost:9346/ping?target=google.com](http://localhost:9346/pi
 | -------------------------------------- | ------------- |
 | PING_EXPORTER_LISTEN                   | [::]:9346     |
 | PING_EXPORTER_DEFAULT_PROTOCOL         | v4            |
+| PING_EXPORTER_RESOLVER                 | system        |
 | PING_EXPORTER_DEFAULT_COUNT            | 5             |
 | PING_EXPORTER_MAX_COUNT                | 30            |
 | PING_EXPORTER_DEFAULT_PING_TIMEOUT     | 1000          |

src/main.rs

@@ -84,7 +84,7 @@ fn run() -> i32 {
     let (stop_sender, stop_receiver) = oneshot::channel();
 
     runtime.spawn(futures::lazy(move || {
-        let server_future = pinger::Pinger::new()
+        let server_future = pinger::Pinger::new(settings.clone())
             .map_err(|_| {
                 error!("Unable to create pinger, please check capabilities");
             }).and_then(move |pinger| http::server(settings, pinger));

src/pinger.rs

@@ -8,6 +8,7 @@ use tokio::timer::Deadline;
 use tokio_ping::{Error as PingError, Pinger as LowLevelPinger};
 
 use resolver::{Error as ResolveError, Resolver};
+use settings::Settings;
 use utils::{NameOrIpAddr, Protocol};
 
 #[derive(Debug, Fail)]
@@ -52,8 +53,8 @@ struct PingerInner {
 }
 
 impl Pinger {
-    pub fn new() -> impl Future<Item = Self, Error = Error> {
-        let resolver_future = Resolver::new().map_err(From::from);
+    pub fn new(settings: Settings) -> impl Future<Item = Self, Error = Error> {
+        let resolver_future = Resolver::new(settings).map_err(From::from);
         let pinger_future = LowLevelPinger::new().map_err(From::from);
         resolver_future
             .join(pinger_future)

src/resolver.rs

@@ -1,10 +1,12 @@
-use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
 
 use futures::{future, Future};
 use rand::{thread_rng, Rng};
+use trust_dns_resolver::config::{self, ResolverConfig, NameServerConfig, ResolverOpts};
 use trust_dns_resolver::error::{ResolveError, ResolveErrorKind};
 use trust_dns_resolver::ResolverFuture;
 
+use settings::Settings;
 use utils::{boxed, NameOrIpAddr, Protocol};
 
 pub struct Resolver {
@@ -30,8 +32,19 @@ impl From<ResolveError> for Error {
 }
 
 impl Resolver {
-    pub fn new() -> impl Future<Item = Self, Error = Error> {
-        let future = future::result(ResolverFuture::from_system_conf()).flatten();
+    pub fn new(settings: Settings) -> impl Future<Item = Self, Error = Error> {
+        let future = future::result(match settings.resolver {
+            Some(resolver_addr) => {
+                let mut config = ResolverConfig::new();
+                config.add_name_server(NameServerConfig {
+                    socket_addr: SocketAddr::new(resolver_addr, 53),
+                    protocol: config::Protocol::Udp,
+                    tls_dns_name: None,
+                });
+                Ok(ResolverFuture::new(config, ResolverOpts::default()))
+            },
+            None => ResolverFuture::from_system_conf(),
+        }).flatten();
 
         future
             .map_err(From::from)

src/settings.rs

@@ -1,6 +1,6 @@
 use std::env;
 use std::fmt;
-use std::net::SocketAddr;
+use std::net::{IpAddr, SocketAddr};
 use std::ops::Deref;
 use std::str::FromStr;
 use std::sync::Arc;
@@ -24,6 +24,10 @@ impl fmt::Display for Settings {
     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
         write!(f, "listen address: {}, ", self.listen)?;
         write!(f, "preferred protocol: {}, ", self.protocol)?;
+        match self.resolver {
+            Some(resolver) => write!(f, "resolver: {}, ", resolver)?,
+            None => write!(f, "resolver: system, ")?,
+        }
         write!(f, "default number of ICMP packets: {}, ", self.count)?;
         write!(f, "maximum number of ICMP packets: {}, ", self.max_count)?;
         write!(
@@ -50,6 +54,7 @@ impl fmt::Display for Settings {
 pub struct SettingsInner {
     pub listen: SocketAddr,
     pub protocol: Protocol,
+    pub resolver: Option<IpAddr>,
     pub count: usize,
     pub max_count: usize,
     pub ping_timeout: u64,
@@ -64,6 +69,11 @@ impl Settings {
             inner: Arc::new(SettingsInner {
                 listen: get_env_or("LISTEN", DEFAULT_LISTEN.clone())?,
                 protocol: get_env_or("DEFAULT_PROTOCOL", Protocol::V4)?,
+                resolver: match get_env_("RESOLVER") {
+                    Ok(resolver) => Some(resolver),
+                    Err(Error::MissingEnvVar { .. }) => None,
+                    Err(err) => return Err(err.into()),
+                },
                 count: get_env_or("DEFAULT_COUNT", 5)?,
                 max_count: get_env_or("MAX_COUNT", 30)?,
                 ping_timeout: get_env_or("DEFAULT_PING_TIMEOUT", 1000)?,