Add blanket implementations of Recorder for some pointer-like types

.github/workflows/ci.yml

@@ -44,16 +44,22 @@ jobs:
     name: Test ${{ matrix.rust_version }}
     runs-on: ubuntu-latest
     strategy:
+      # 1.70 is the MSRV for the project, which currently does not match the version specified in
+      # the rust-toolchain.toml file as metrics-observer requires 1.74 to build. See
+      # https://github.com/metrics-rs/metrics/pull/505#discussion_r1724092556 for more information.
       matrix:
-        rust_version: ['stable', 'nightly']
+        rust_version: ['stable', 'nightly', '1.70']
+        include:
+          - rust_version: '1.70'
+            exclude-packages: '--exclude metrics-observer'
     steps:
     - uses: actions/checkout@v3
     - name: Install Protobuf Compiler
       run: sudo apt-get install protobuf-compiler
     - name: Install Rust ${{ matrix.rust_version }}
       run: rustup install ${{ matrix.rust_version }}
     - name: Run Tests
-      run: cargo +${{ matrix.rust_version }} test --all-features --workspace
+      run: cargo +${{ matrix.rust_version }} test --all-features --workspace ${{ matrix.exclude-packages }}
   docs:
     runs-on: ubuntu-latest
     env:

clippy.toml

@@ -1 +1,2 @@
 too-many-lines-threshold = 150
+ignore-interior-mutability = ["metrics::key::Key"]

metrics-exporter-prometheus/src/common.rs

@@ -80,6 +80,7 @@ pub enum BuildError {
     ZeroBucketDuration,
 }
 
+#[derive(Debug)]
 pub struct Snapshot {
     pub counters: HashMap<String, HashMap<Vec<String>, u64>>,
     pub gauges: HashMap<String, HashMap<Vec<String>, f64>>,

metrics-exporter-prometheus/src/distribution.rs

@@ -15,7 +15,7 @@ const DEFAULT_SUMMARY_BUCKET_COUNT: NonZeroU32 = match NonZeroU32::new(3) {
 const DEFAULT_SUMMARY_BUCKET_DURATION: Duration = Duration::from_secs(20);
 
 /// Distribution type.
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub enum Distribution {
     /// A Prometheus histogram.
     ///
@@ -33,7 +33,10 @@ pub enum Distribution {
 
 impl Distribution {
     /// Creates a histogram distribution.
-    #[warn(clippy::missing_panics_doc)]
+    ///
+    /// # Panics
+    ///
+    /// Panics if `buckets` is empty.
     pub fn new_histogram(buckets: &[f64]) -> Distribution {
         let hist = Histogram::new(buckets).expect("buckets should never be empty");
         Distribution::Histogram(hist)
@@ -134,14 +137,14 @@ impl DistributionBuilder {
     }
 }
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 struct Bucket {
     begin: Instant,
     summary: Summary,
 }
 
 /// A `RollingSummary` manages a list of [Summary] so that old results can be expired.
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct RollingSummary {
     // Buckets are ordered with the latest buckets first.  The buckets are kept in alignment based
     // on the instant of the first added bucket and the bucket_duration.  There may be gaps in the
@@ -299,8 +302,11 @@ mod tests {
         let snapshot = summary.snapshot(clock.now());
 
         assert_eq!(0, snapshot.count());
-        assert_eq!(f64::INFINITY, snapshot.min());
-        assert_eq!(f64::NEG_INFINITY, snapshot.max());
+        #[allow(clippy::float_cmp)]
+        {
+            assert_eq!(f64::INFINITY, snapshot.min());
+            assert_eq!(f64::NEG_INFINITY, snapshot.max());
+        }
         assert_eq!(None, snapshot.quantile(0.5));
     }
 
@@ -318,8 +324,11 @@ mod tests {
 
         let snapshot = summary.snapshot(clock.now());
 
-        assert_eq!(42.0, snapshot.min());
-        assert_eq!(42.0, snapshot.max());
+        #[allow(clippy::float_cmp)]
+        {
+            assert_eq!(42.0, snapshot.min());
+            assert_eq!(42.0, snapshot.max());
+        }
         // 42 +/- (42 * 0.0001)
         assert!(Some(41.9958) < snapshot.quantile(0.5));
         assert!(Some(42.0042) > snapshot.quantile(0.5));

metrics-exporter-prometheus/src/exporter/builder.rs

@@ -33,6 +33,7 @@ use super::ExporterConfig;
 use super::ExporterFuture;
 
 /// Builder for creating and installing a Prometheus recorder/exporter.
+#[derive(Debug)]
 pub struct PrometheusBuilder {
     #[cfg_attr(not(any(feature = "http-listener", feature = "push-gateway")), allow(dead_code))]
     exporter_config: ExporterConfig,
@@ -560,8 +561,7 @@ mod tests {
         gauge1.set(-3.14);
         let rendered = handle.render();
         let expected_gauge = format!(
-            "{}# TYPE basic_gauge gauge\nbasic_gauge{{wutang=\"forever\"}} -3.14\n\n",
-            expected_counter
+            "{expected_counter}# TYPE basic_gauge gauge\nbasic_gauge{{wutang=\"forever\"}} -3.14\n\n",
         );
 
         assert_eq!(rendered, expected_gauge);
@@ -579,7 +579,7 @@ mod tests {
             "basic_histogram_count 1\n",
             "\n"
         );
-        let expected_histogram = format!("{}{}", expected_gauge, histogram_data);
+        let expected_histogram = format!("{expected_gauge}{histogram_data}");
 
         assert_eq!(rendered, expected_histogram);
     }

metrics-exporter-prometheus/src/exporter/http_listener.rs

@@ -32,6 +32,7 @@ enum ListenerType {
 }
 
 /// Error type for HTTP listening.
+#[derive(Debug)]
 pub enum HttpListeningError {
     Hyper(hyper::Error),
     Io(std::io::Error),
@@ -59,11 +60,11 @@ impl HttpListeningExporter {
                     continue;
                 }
             };
-            self.process_tcp_stream(stream).await;
+            self.process_tcp_stream(stream);
         }
     }
 
-    async fn process_tcp_stream(&self, stream: TcpStream) {
+    fn process_tcp_stream(&self, stream: TcpStream) {
         let is_allowed = self.check_tcp_allowed(&stream);
         let handle = self.handle.clone();
         let service = service_fn(move |req: Request<body::Incoming>| {
@@ -107,12 +108,12 @@ impl HttpListeningExporter {
                     continue;
                 }
             };
-            self.process_uds_stream(stream).await;
+            self.process_uds_stream(stream);
         }
     }
 
     #[cfg(feature = "uds-listener")]
-    async fn process_uds_stream(&self, stream: UnixStream) {
+    fn process_uds_stream(&self, stream: UnixStream) {
         let handle = self.handle.clone();
         let service = service_fn(move |req: Request<body::Incoming>| {
             let handle = handle.clone();

metrics-exporter-prometheus/src/exporter/mod.rs

@@ -14,6 +14,7 @@ use hyper::Uri;
 
 /// Error types possible from an exporter
 #[cfg(any(feature = "http-listener", feature = "push-gateway"))]
+#[derive(Debug)]
 pub enum ExporterError {
     #[cfg(feature = "http-listener")]
     HttpListener(HttpListeningError),
@@ -24,14 +25,14 @@ pub enum ExporterError {
 pub type ExporterFuture = Pin<Box<dyn Future<Output = Result<(), ExporterError>> + Send + 'static>>;
 
 #[cfg(feature = "http-listener")]
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 enum ListenDestination {
     Tcp(SocketAddr),
     #[cfg(feature = "uds-listener")]
     Uds(std::path::PathBuf),
 }
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 enum ExporterConfig {
     // Run an HTTP listener on the given `listen_address`.
     #[cfg(feature = "http-listener")]

metrics-exporter-prometheus/src/exporter/push_gateway.rs

@@ -94,7 +94,7 @@ fn basic_auth(username: &str, password: Option<&str>) -> HeaderValue {
     header
 }
 
-#[cfg(all(test))]
+#[cfg(test)]
 mod tests {
     use super::basic_auth;
 

metrics-exporter-prometheus/src/formatting.rs

@@ -110,35 +110,37 @@ pub fn write_metric_line<T, T2>(
 /// [data model]: https://prometheus.io/docs/concepts/data_model/#metric-names-and-labels
 pub fn sanitize_metric_name(name: &str) -> String {
     // The first character must be [a-zA-Z_:], and all subsequent characters must be [a-zA-Z0-9_:].
-    let mut out = String::with_capacity(name.len());
-    let mut is_invalid: fn(char) -> bool = invalid_metric_name_start_character;
-    for c in name.chars() {
-        if is_invalid(c) {
-            out.push('_');
-        } else {
-            out.push(c);
-        }
-        is_invalid = invalid_metric_name_character;
-    }
-    out
+    name.chars()
+        .enumerate()
+        .map(|(i, c)| {
+            if i == 0 && valid_metric_name_start_character(c)
+                || i != 0 && valid_metric_name_character(c)
+            {
+                c
+            } else {
+                '_'
+            }
+        })
+        .collect()
 }
 
 /// Sanitizes a label key to be valid under the Prometheus [data model].
 ///
 /// [data model]: https://prometheus.io/docs/concepts/data_model/#metric-names-and-labels
 pub fn sanitize_label_key(key: &str) -> String {
     // The first character must be [a-zA-Z_], and all subsequent characters must be [a-zA-Z0-9_].
-    let mut out = String::with_capacity(key.len());
-    let mut is_invalid: fn(char) -> bool = invalid_label_key_start_character;
-    for c in key.chars() {
-        if is_invalid(c) {
-            out.push('_');
-        } else {
-            out.push(c);
-        }
-        is_invalid = invalid_label_key_character;
-    }
-    out
+    key.chars()
+        .enumerate()
+        .map(|(i, c)| {
+            if i == 0 && valid_label_key_start_character(c)
+                || i != 0 && valid_label_key_character(c)
+            {
+                c
+            } else {
+                '_'
+            }
+        })
+        .collect()
 }
 
 /// Sanitizes a label value to be valid under the Prometheus [data model].
@@ -209,35 +211,35 @@ fn sanitize_label_value_or_description(value: &str, is_desc: bool) -> String {
 }
 
 #[inline]
-fn invalid_metric_name_start_character(c: char) -> bool {
+fn valid_metric_name_start_character(c: char) -> bool {
     // Essentially, needs to match the regex pattern of [a-zA-Z_:].
-    !(c.is_ascii_alphabetic() || c == '_' || c == ':')
+    c.is_ascii_alphabetic() || c == '_' || c == ':'
 }
 
 #[inline]
-fn invalid_metric_name_character(c: char) -> bool {
+fn valid_metric_name_character(c: char) -> bool {
     // Essentially, needs to match the regex pattern of [a-zA-Z0-9_:].
-    !(c.is_ascii_alphanumeric() || c == '_' || c == ':')
+    c.is_ascii_alphanumeric() || c == '_' || c == ':'
 }
 
 #[inline]
-fn invalid_label_key_start_character(c: char) -> bool {
+fn valid_label_key_start_character(c: char) -> bool {
     // Essentially, needs to match the regex pattern of [a-zA-Z_].
-    !(c.is_ascii_alphabetic() || c == '_')
+    c.is_ascii_alphabetic() || c == '_'
 }
 
 #[inline]
-fn invalid_label_key_character(c: char) -> bool {
+fn valid_label_key_character(c: char) -> bool {
     // Essentially, needs to match the regex pattern of [a-zA-Z0-9_].
-    !(c.is_ascii_alphanumeric() || c == '_')
+    c.is_ascii_alphanumeric() || c == '_'
 }
 
 #[cfg(test)]
 mod tests {
     use crate::formatting::{
-        invalid_label_key_character, invalid_label_key_start_character,
-        invalid_metric_name_character, invalid_metric_name_start_character, sanitize_description,
-        sanitize_label_key, sanitize_label_value, sanitize_metric_name,
+        sanitize_description, sanitize_label_key, sanitize_label_value, sanitize_metric_name,
+        valid_label_key_character, valid_label_key_start_character, valid_metric_name_character,
+        valid_metric_name_start_character,
     };
     use proptest::prelude::*;
 
@@ -321,11 +323,11 @@ mod tests {
             let as_chars = result.chars().collect::<Vec<_>>();
 
             if let Some(c) = as_chars.first() {
-                assert_eq!(false, invalid_metric_name_start_character(*c),
+                assert!(valid_metric_name_start_character(*c),
                     "first character of metric name was not valid");
             }
 
-            assert!(!as_chars.iter().any(|c| invalid_metric_name_character(*c)),
+            assert!(as_chars.iter().all(|c| valid_metric_name_character(*c)),
                 "invalid character in metric name");
         }
 
@@ -335,7 +337,7 @@ mod tests {
             let as_chars = result.chars().collect::<Vec<_>>();
 
             if let Some(c) = as_chars.first() {
-                assert_eq!(false, invalid_label_key_start_character(*c),
+                assert!(valid_label_key_start_character(*c),
                     "first character of label key was not valid");
             }
 
@@ -353,7 +355,7 @@ mod tests {
                 }
             }*/
 
-            assert!(!as_chars.iter().any(|c| invalid_label_key_character(*c)),
+            assert!(as_chars.iter().all(|c| valid_label_key_character(*c)),
                 "invalid character in label key");
         }
 
@@ -369,7 +371,7 @@ mod tests {
             let as_chars = delayered_backslashes.chars().collect::<Vec<_>>();
 
             // If the first character is a double quote, then we messed up.
-            assert!(as_chars.first().map(|c| *c != '"').unwrap_or(true),
+            assert!(as_chars.first().map_or(true, |c| *c != '"'),
                 "first character cannot be a double quote: {}", result);
 
             // Now look for unescaped characters in the rest of the string, in a windowed fashion.

metrics-exporter-prometheus/src/recorder.rs

@@ -15,6 +15,7 @@ use crate::formatting::{
 };
 use crate::registry::GenerationalAtomicStorage;
 
+#[derive(Debug)]
 pub(crate) struct Inner {
     pub registry: Registry<Key, GenerationalAtomicStorage>,
     pub recency: Recency<Key>,
@@ -214,6 +215,7 @@ impl Inner {
 /// Most users will not need to interact directly with the recorder, and can simply deal with the
 /// builder methods on [`PrometheusBuilder`](crate::PrometheusBuilder) for building and installing
 /// the recorder/exporter.
+#[derive(Debug)]
 pub struct PrometheusRecorder {
     inner: Arc<Inner>,
 }
@@ -275,7 +277,7 @@ impl Recorder for PrometheusRecorder {
 /// handled directly by the HTTP listener, or push gateway background task.  [`PrometheusHandle`]
 /// allows rendering a snapshot of the current metrics stored by an installed [`PrometheusRecorder`]
 /// as a payload conforming to the Prometheus exposition format.
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct PrometheusHandle {
     inner: Arc<Inner>,
 }

metrics-exporter-prometheus/src/registry.rs

@@ -7,6 +7,7 @@ use quanta::Instant;
 pub type GenerationalAtomicStorage = GenerationalStorage<AtomicStorage>;
 
 /// Atomic metric storage for the prometheus exporter.
+#[derive(Debug)]
 pub struct AtomicStorage;
 
 impl<K> metrics_util::registry::Storage<K> for AtomicStorage {
@@ -28,6 +29,7 @@ impl<K> metrics_util::registry::Storage<K> for AtomicStorage {
 }
 
 /// An `AtomicBucket` newtype wrapper that tracks the time of value insertion.
+#[derive(Debug)]
 pub struct AtomicBucketInstant<T> {
     inner: AtomicBucket<(T, Instant)>,
 }