feat(metrics): Add option to send hostname with every metric

CHANGELOG.md

@@ -16,6 +16,7 @@
 - GCS, S3, HTTP, and local filesystem sources: Attempt to retry failed downloads at least once. ([#485](https://github.com/getsentry/symbolicator/pull/485))
 - Refresh symcaches when a new `BcSymbolMap` becomes available. ([#493](https://github.com/getsentry/symbolicator/pull/493))
 - Cache download failures and do not retry the download for a while ([#484](https://github.com/getsentry/symbolicator/pull/484), [#501](https://github.com/getsentry/symbolicator/pull/501))
+- New configuration option `hostname_tag` ([#513](https://github.com/getsentry/symbolicator/pull/513))
 
 ### Tools
 

crates/symbolicator/Cargo.toml

@@ -22,6 +22,7 @@ fragile = "1.0.0" # used for vendoring sentry-actix
 futures = { version = "0.3.12", features = ["compat"] }
 futures01 = { version = "0.1.29", package = "futures" }
 glob = "0.3.0"
+hostname = "0.3.1"
 humantime-serde = "1.0.1"
 ipnetwork = "0.18.0"
 jsonwebtoken = "7.2.0"

crates/symbolicator/src/cli.rs

@@ -73,7 +73,13 @@ pub fn execute() -> Result<()> {
 
     logging::init_logging(&config);
     if let Some(ref statsd) = config.metrics.statsd {
-        metrics::configure_statsd(&config.metrics.prefix, statsd);
+        let hostname = config.metrics.hostname_tag.clone().and_then(|tag| {
+            hostname::get()
+                .ok()
+                .and_then(|s| s.into_string().ok())
+                .map(|name| (tag, name))
+        });
+        metrics::configure_statsd(&config.metrics.prefix, statsd, hostname);
     }
 
     procspawn::ProcConfig::new()

crates/symbolicator/src/config.rs

@@ -55,6 +55,8 @@ pub struct Metrics {
     pub statsd: Option<String>,
     /// The prefix that should be added to all metrics.
     pub prefix: String,
+    /// A tag name to report the hostname to, for each metric. Defaults to not sending such a tag.
+    pub hostname_tag: Option<String>,
 }
 
 impl Default for Metrics {
@@ -65,6 +67,7 @@ impl Default for Metrics {
                 Err(_) => None,
             },
             prefix: "symbolicator".into(),
+            hostname_tag: None,
         }
     }
 }

crates/symbolicator/src/metrics.rs

@@ -1,16 +1,20 @@
 //! Provides access to the metrics sytem.
 use std::net::ToSocketAddrs;
+use std::ops::{Deref, DerefMut};
 use std::sync::Arc;
 
-use cadence::{StatsdClient, UdpMetricSink};
+use cadence::{Metric, MetricBuilder, StatsdClient, UdpMetricSink};
 use parking_lot::RwLock;
 
+type Hostname = String;
+type HostnameTag = String;
+
 lazy_static::lazy_static! {
-    static ref METRICS_CLIENT: RwLock<Option<Arc<StatsdClient>>> = RwLock::new(None);
+    static ref METRICS_CLIENT: RwLock<Option<Arc<MetricsClient>>> = RwLock::new(None);
 }
 
 thread_local! {
-    static CURRENT_CLIENT: Option<Arc<StatsdClient>> = METRICS_CLIENT.read().clone();
+    static CURRENT_CLIENT: Option<Arc<MetricsClient>> = METRICS_CLIENT.read().clone();
 }
 
 /// Internal prelude for the macro
@@ -25,21 +29,64 @@ pub mod prelude {
     pub use cadence::prelude::*;
 }
 
+#[derive(Debug)]
+pub struct MetricsClient {
+    /// The raw statsd client.
+    pub statsd_client: StatsdClient,
+    /// The hostname and the tag to report it to.
+    pub hostname: Option<(HostnameTag, Hostname)>,
+}
+
+impl MetricsClient {
+    #[inline(always)]
+    pub fn send_metric<'a, T>(&'a self, mut metric: MetricBuilder<'a, '_, T>)
+    where
+        T: Metric + From<String>,
+    {
+        if let Some((tag, name)) = self.hostname.as_ref() {
+            metric = metric.with_tag(tag, name);
+        }
+        metric.send()
+    }
+}
+
+impl Deref for MetricsClient {
+    type Target = StatsdClient;
+
+    fn deref(&self) -> &Self::Target {
+        &self.statsd_client
+    }
+}
+
+impl DerefMut for MetricsClient {
+    fn deref_mut(&mut self) -> &mut StatsdClient {
+        &mut self.statsd_client
+    }
+}
+
 /// Set a new statsd client.
-pub fn set_client(statsd_client: StatsdClient) {
-    *METRICS_CLIENT.write() = Some(Arc::new(statsd_client));
+pub fn set_client(client: MetricsClient) {
+    *METRICS_CLIENT.write() = Some(Arc::new(client));
 }
 
 /// Tell the metrics system to report to statsd.
-pub fn configure_statsd<A: ToSocketAddrs>(prefix: &str, host: A) {
+pub fn configure_statsd<A: ToSocketAddrs>(
+    prefix: &str,
+    host: A,
+    hostname: Option<(HostnameTag, Hostname)>,
+) {
     let addrs: Vec<_> = host.to_socket_addrs().unwrap().collect();
     if !addrs.is_empty() {
         log::info!("Reporting metrics to statsd at {}", addrs[0]);
     }
     let socket = std::net::UdpSocket::bind("0.0.0.0:0").unwrap();
     socket.set_nonblocking(true).unwrap();
     let sink = UdpMetricSink::from(&addrs[..], socket).unwrap();
-    set_client(StatsdClient::from_sink(prefix, sink));
+    let statsd_client = StatsdClient::from_sink(prefix, sink);
+    set_client(MetricsClient {
+        statsd_client,
+        hostname,
+    });
 }
 
 /// Invoke a callback with the current statsd client.
@@ -49,7 +96,7 @@ pub fn configure_statsd<A: ToSocketAddrs>(prefix: &str, host: A) {
 #[inline(always)]
 pub fn with_client<F, R>(f: F) -> R
 where
-    F: FnOnce(&StatsdClient) -> R,
+    F: FnOnce(&MetricsClient) -> R,
     R: Default,
 {
     CURRENT_CLIENT.with(|client| {
@@ -68,57 +115,63 @@ macro_rules! metric {
     (counter($id:expr) += $value:expr $(, $k:expr => $v:expr)* $(,)?) => {{
         use $crate::metrics::_pred::*;
         $crate::metrics::with_client(|client| {
-            client.count_with_tags($id, $value)
-                $(.with_tag($k, $v))*
-                .send();
+            client.send_metric(
+                client.count_with_tags($id, $value)
+                    $(.with_tag($k, $v))*
+            );
         })
     }};
     (counter($id:expr) -= $value:expr $(, $k:expr => $v:expr)* $(,)?) => {{
         use $crate::metrics::_pred::*;
         $crate::metrics::with_client(|client| {
-            client.count_with_tags($id, -$value)
-                $(.with_tag($k, $v))*
-                .send();
+            client.send_metric(
+                client.count_with_tags($id, -$value)
+                    $(.with_tag($k, $v))*
+             );
         })
     }};
 
     // gauges
     (gauge($id:expr) = $value:expr $(, $k:expr => $v:expr)* $(,)?) => {{
         use $crate::metrics::_pred::*;
         $crate::metrics::with_client(|client| {
-            client.gauge_with_tags($id, $value)
-                $(.with_tag($k, $v))*
-                .send();
+            client.send_metric(
+                client.gauge_with_tags($id, $value)
+                    $(.with_tag($k, $v))*
+            );
         })
     }};
 
     // timers
     (timer($id:expr) = $value:expr $(, $k:expr => $v:expr)* $(,)?) => {{
         use $crate::metrics::_pred::*;
         $crate::metrics::with_client(|client| {
-            client.time_duration_with_tags($id, $value)
-                $(.with_tag($k, $v))*
-                .send();
+            client.send_metric(
+                client.time_duration_with_tags($id, $value)
+                    $(.with_tag($k, $v))*
+            );
         })
     }};
 
     // we use statsd timers to send things such as filesizes as well.
     (time_raw($id:expr) = $value:expr $(, $k:expr => $v:expr)* $(,)?) => {{
         use $crate::metrics::_pred::*;
         $crate::metrics::with_client(|client| {
-            client.time_with_tags($id, $value)
-                $(.with_tag($k, $v))*
-                .send();
+            client.send_metric(
+                client.time_with_tags($id, $value)
+                    $(.with_tag($k, $v))*
+            );
         })
     }};
 
     // histograms
     (histogram($id:expr) = $value:expr $(, $k:expr => $v:expr)* $(,)?) => {{
         use $crate::metrics::_pred::*;
         $crate::metrics::with_client(|client| {
-            client.histogram_with_tags($id, $value)
-                $(.with_tag($k, $v))*
-                .send();
+            client.send_metric(
+                client.histogram_with_tags($id, $value)
+                    $(.with_tag($k, $v))*
+            );
         })
     }};
 }

docs/index.md

@@ -59,6 +59,7 @@ metrics:
       environment variable or in case it is not defined, then it defaults to `null`,
       which disables metric submission.
     - `prefix`: A prefix for every metric, defaults to `symbolicator`.
+    - `hostname_tag`: If set, report the current hostname under the given tag name for all metrics.
 - `sentry_dsn`: DSN to a Sentry project for internal error reporting. Defaults
   to `null`, which disables reporting to Sentry.
 - `sources`: An optional list of preconfigured sources. If these are configured