Fix/expand a few comments

backend/telemetry_core/src/aggregator/aggregator_set.rs

@@ -63,7 +63,7 @@ impl AggregatorSet {
                     };
 
                     // Lock, update the stored metrics and drop the lock immediately.
-                    // We discard any error; if somethign went wrong talking to the inner loop,
+                    // We discard any error; if something went wrong talking to the inner loop,
                     // it's probably a fatal error
                     {
                         inner.metrics.lock().unwrap()[idx] = metrics;

backend/telemetry_core/src/main.rs

@@ -485,13 +485,16 @@ where
 async fn return_prometheus_metrics(aggregator: AggregatorSet) -> Response<hyper::Body> {
     let metrics = aggregator.latest_metrics();
 
-    // Instead of using the rust prometheus library, we just split out the text format that prometheus expects
+    // Instead of using the rust prometheus library (which is optimised around global variables updated across a codebase),
-    // ourselves, using whatever the latest metrics that we've captured so far are. See:
+    // we just split out the text format that prometheus expects ourselves, using whatever the latest metrics that we've
+    // captured so far from the aggregators are. See:
     //
     // https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md#text-format-details
     //
     // For an example and explanation of this text based format. The minimal output we produce here seems to
     // be handled correctly when pointing a current version of prometheus at it.
+    //
+    // Note: '{{' and '}}' are just escaped versions of '{' and '}' in Rust fmt strings.
     let mut s = String::new();
     for (idx, m) in metrics.iter().enumerate() {
         s.push_str(&format!(

backend/telemetry_core/tests/soak_tests.rs

@@ -46,17 +46,17 @@ use test_utils::workspace::{start_server, CoreOpts, ServerOpts, ShardOpts};
 ///
 /// To start up 4 telemetry_shards and 1 telemetry_core with 10 feeds and 100 nodes:
 /// ```sh
-/// SOAK_TEST_ARGS='--feeds 10 --nodes 100 --shards 4' cargo test --release -- realistic_soak_test --ignored --nocapture
+/// SOAK_TEST_ARGS='--feeds 10 --nodes 100 --shards 4' cargo test --release -- soak_test --ignored --nocapture
 /// ```
 ///
 /// You can also run this test against the pre-sharding actix binary with something like this:
 /// ```sh
-/// TELEMETRY_BIN=~/old_telemetry_binary SOAK_TEST_ARGS='--feeds 100 --nodes 100 --shards 4' cargo test --release -- realistic_soak_test --ignored --nocapture
+/// TELEMETRY_BIN=~/old_telemetry_binary SOAK_TEST_ARGS='--feeds 100 --nodes 100 --shards 4' cargo test --release -- soak_test --ignored --nocapture
 /// ```
 ///
 /// Or, you can run it against existing processes on the network with something like this:
 /// ```sh
-/// TELEMETRY_SUBMIT_HOSTS='127.0.0.1:8001' TELEMETRY_FEED_HOST='127.0.0.1:8000' SOAK_TEST_ARGS='--feeds 100 --nodes 100 --shards 4' cargo test --release -- realistic_soak_test --ignored --nocapture
+/// TELEMETRY_SUBMIT_HOSTS='127.0.0.1:8001' TELEMETRY_FEED_HOST='127.0.0.1:8000' SOAK_TEST_ARGS='--feeds 100 --nodes 100 --shards 4' cargo test --release -- soak_test --ignored --nocapture
 /// ```
 ///
 #[ignore]
@@ -70,14 +70,14 @@ pub fn soak_test() {
         .thread_name("telemetry_test_runner")
         .build()
         .unwrap()
-        .block_on(run_realistic_soak_test(opts));
+        .block_on(run_soak_test(opts));
 }
 
 /// A general soak test runner.
 /// This test sends realistic messages from connected nodes
 /// so that we can see how things react under more normal
 /// circumstances
-async fn run_realistic_soak_test(opts: SoakTestOpts) {
+async fn run_soak_test(opts: SoakTestOpts) {
     let mut server = start_server(
         ServerOpts {
             release_mode: true,