Remove extra new lines

metrics-exporter-prometheus/src/lib.rs

@@ -13,13 +13,14 @@ use metrics_util::{
     parse_quantiles, CompositeKey, Handle, Histogram, MetricKind, Quantile, Registry,
 };
 use parking_lot::RwLock;
+use std::collections::HashMap;
 use std::io;
 use std::iter::FromIterator;
 use std::net::{IpAddr, Ipv4Addr, SocketAddr};
 use std::sync::Arc;
 #[cfg(feature = "tokio-exporter")]
 use std::thread;
-use std::{collections::HashMap, time::SystemTime};
+use std::time::SystemTime;
 use thiserror::Error as ThisError;
 #[cfg(feature = "tokio-exporter")]
 use tokio::{pin, runtime, select};
@@ -180,7 +181,15 @@ impl Inner {
             mut distributions,
         } = self.get_recent_metrics();
 
-        let mut output = String::new();
+        let ts = SystemTime::now()
+            .duration_since(SystemTime::UNIX_EPOCH)
+            .map(|d| d.as_secs())
+            .unwrap_or(0);
+
+        let mut output = format!(
+            "# metrics snapshot (ts={}) (prometheus exposition format)\n",
+            ts
+        );
 
         let descriptions = self.descriptions.read();
 
@@ -203,7 +212,6 @@ impl Inner {
                 output.push_str(value.to_string().as_str());
                 output.push_str("\n");
             }
-            output.push_str("\n");
         }
 
         for (name, mut by_labels) in gauges.drain() {
@@ -225,7 +233,6 @@ impl Inner {
                 output.push_str(value.to_string().as_str());
                 output.push_str("\n");
             }
-            output.push_str("\n");
         }
 
         let mut sorted_overrides = self
@@ -308,8 +315,6 @@ impl Inner {
                 output.push_str(count.to_string().as_str());
                 output.push_str("\n");
             }
-
-            output.push_str("\n");
         }
 
         output