Remove labels parametrisation (#63)

* Stop leaking 'le', 'quantile' in Summary/Histogram labels, remove labels parametrisation

* chore: Remove base labels protocol and add ExpressibleByArrayLiteral

* chore: Cleanup documentation. Remove deprecations

Co-authored-by: Jari (LotU) <[email protected]>

Author: avolokhov

README.md

@@ -102,20 +102,18 @@ summary.observe(4.7) // Observe the given value
 ```
 
 ## Labels
-All metric types support adding labels, allowing for grouping of related metrics.
+All metric types support adding labels, allowing for grouping of related metrics. Labels are passed when recording values to your metric as an instance of `DimensionLabels`, or as an array of `(String, String)`.
 
 Example with a counter:
 
 ```swift
-struct RouteLabels: MetricLabels {
-   var route: String = "*"
-}
-
-let counter = myProm.createCounter(forType: Int.self, named: "my_counter", helpText: "Just a counter", withLabelType: RouteLabels.self)
+let counter = myProm.createCounter(forType: Int.self, named: "my_counter", helpText: "Just a counter")
 
-let counter = prom.createCounter(forType: Int.self, named: "my_counter", helpText: "Just a counter", withLabelType: RouteLabels.self)
+let counter = prom.createCounter(forType: Int.self, named: "my_counter", helpText: "Just a counter")
 
-counter.inc(12, .init(route: "/"))
+counter.inc(12, .init([("route", "/users")]))
+// OR
+counter.inc(12, [("route", "/users")])
 ```
 
 # Exporting

Sources/Prometheus/MetricTypes/Counter.swift

@@ -3,7 +3,7 @@ import NIOConcurrencyHelpers
 /// Prometheus Counter metric
 ///
 /// See: https://prometheus.io/docs/concepts/metric_types/#counter
-public class PromCounter<NumType: Numeric, Labels: MetricLabels>: PromMetric, PrometheusHandled {
+public class PromCounter<NumType: Numeric>: PromMetric, PrometheusHandled {
     /// Prometheus instance that created this Counter
     internal weak var prometheus: PrometheusClient?
 
@@ -22,7 +22,7 @@ public class PromCounter<NumType: Numeric, Labels: MetricLabels>: PromMetric, Pr
     private let initialValue: NumType
 
     /// Storage of values that have labels attached
-    internal var metrics: [Labels: NumType] = [:]
+    internal var metrics: [DimensionLabels: NumType] = [:]
 
     /// Lock used for thread safety
     internal let lock: Lock
@@ -75,7 +75,7 @@ public class PromCounter<NumType: Numeric, Labels: MetricLabels>: PromMetric, Pr
     ///     - labels: Labels to attach to the value
     ///
     @discardableResult
-    public func inc(_ amount: NumType = 1, _ labels: Labels? = nil) -> NumType {
+    public func inc(_ amount: NumType = 1, _ labels: DimensionLabels? = nil) -> NumType {
         return self.lock.withLock {
             if let labels = labels {
                 var val = self.metrics[labels] ?? self.initialValue
@@ -95,7 +95,7 @@ public class PromCounter<NumType: Numeric, Labels: MetricLabels>: PromMetric, Pr
     ///     - labels: Labels to get the value for
     ///
     /// - Returns: The value of the Counter attached to the provided labels
-    public func get(_ labels: Labels? = nil) -> NumType {
+    public func get(_ labels: DimensionLabels? = nil) -> NumType {
         return self.lock.withLock {
             if let labels = labels {
                 return self.metrics[labels] ?? initialValue

Sources/Prometheus/MetricTypes/Gauge.swift

@@ -5,7 +5,7 @@ import NIOConcurrencyHelpers
 /// Prometheus Gauge metric
 ///
 /// See https://prometheus.io/docs/concepts/metric_types/#gauge
-public class PromGauge<NumType: DoubleRepresentable, Labels: MetricLabels>: PromMetric, PrometheusHandled {
+public class PromGauge<NumType: DoubleRepresentable>: PromMetric, PrometheusHandled {
     /// Prometheus instance that created this Gauge
     internal weak var prometheus: PrometheusClient?
 
@@ -24,7 +24,7 @@ public class PromGauge<NumType: DoubleRepresentable, Labels: MetricLabels>: Prom
     private let initialValue: NumType
 
     /// Storage of values that have labels attached
-    private var metrics: [Labels: NumType] = [:]
+    private var metrics: [DimensionLabels: NumType] = [:]
 
     /// Lock used for thread safety
     private let lock: Lock
@@ -78,7 +78,7 @@ public class PromGauge<NumType: DoubleRepresentable, Labels: MetricLabels>: Prom
     ///
     /// - Returns: The value of the Gauge attached to the provided labels
     @discardableResult
-    public func setToCurrentTime(_ labels: Labels? = nil) -> NumType {
+    public func setToCurrentTime(_ labels: DimensionLabels? = nil) -> NumType {
         return self.set(.init(Date().timeIntervalSince1970), labels)
     }
 
@@ -94,7 +94,7 @@ public class PromGauge<NumType: DoubleRepresentable, Labels: MetricLabels>: Prom
     ///
     /// - Returns: The same type of function passed in for `body`, but wrapped to track progress.
     @inlinable
-    public func trackInProgress<T>(_ labels: Labels? = nil, _ body: @escaping () throws -> T) -> (() throws -> T) {
+    public func trackInProgress<T>(_ labels: DimensionLabels? = nil, _ body: @escaping () throws -> T) -> (() throws -> T) {
         return {
             self.inc()
             defer {
@@ -109,7 +109,7 @@ public class PromGauge<NumType: DoubleRepresentable, Labels: MetricLabels>: Prom
     ///     - labels: Labels to attach to the resulting value.
     ///     - body: Closure to run & record execution time of.
     @inlinable
-    public func time<T>(_ labels: Labels? = nil, _ body: @escaping () throws -> T) rethrows -> T {
+    public func time<T>(_ labels: DimensionLabels? = nil, _ body: @escaping () throws -> T) rethrows -> T {
         let start = DispatchTime.now().uptimeNanoseconds
         defer {
             let delta = Double(DispatchTime.now().uptimeNanoseconds - start)
@@ -127,7 +127,7 @@ public class PromGauge<NumType: DoubleRepresentable, Labels: MetricLabels>: Prom
     ///
     /// - Returns: The value of the Gauge attached to the provided labels
     @discardableResult
-    public func set(_ amount: NumType, _ labels: Labels? = nil) -> NumType {
+    public func set(_ amount: NumType, _ labels: DimensionLabels? = nil) -> NumType {
         return self.lock.withLock {
             if let labels = labels {
                 self.metrics[labels] = amount
@@ -147,7 +147,7 @@ public class PromGauge<NumType: DoubleRepresentable, Labels: MetricLabels>: Prom
     ///
     /// - Returns: The value of the Gauge attached to the provided labels
     @discardableResult
-    public func inc(_ amount: NumType, _ labels: Labels? = nil) -> NumType {
+    public func inc(_ amount: NumType, _ labels: DimensionLabels? = nil) -> NumType {
         return self.lock.withLock {
             if let labels = labels {
                 var val = self.metrics[labels] ?? self.initialValue
@@ -168,7 +168,7 @@ public class PromGauge<NumType: DoubleRepresentable, Labels: MetricLabels>: Prom
     ///
     /// - Returns: The value of the Gauge attached to the provided labels
     @discardableResult
-    public func inc(_ labels: Labels? = nil) -> NumType {
+    public func inc(_ labels: DimensionLabels? = nil) -> NumType {
         return self.inc(1, labels)
     }
 
@@ -180,7 +180,7 @@ public class PromGauge<NumType: DoubleRepresentable, Labels: MetricLabels>: Prom
     ///
     /// - Returns: The value of the Gauge attached to the provided labels
     @discardableResult
-    public func dec(_ amount: NumType, _ labels: Labels? = nil) -> NumType {
+    public func dec(_ amount: NumType, _ labels: DimensionLabels? = nil) -> NumType {
         return self.lock.withLock {
             if let labels = labels {
                 var val = self.metrics[labels] ?? self.initialValue
@@ -201,7 +201,7 @@ public class PromGauge<NumType: DoubleRepresentable, Labels: MetricLabels>: Prom
     ///
     /// - Returns: The value of the Gauge attached to the provided labels
     @discardableResult
-    public func dec(_ labels: Labels? = nil) -> NumType {
+    public func dec(_ labels: DimensionLabels? = nil) -> NumType {
         return self.dec(1, labels)
     }
 
@@ -211,7 +211,7 @@ public class PromGauge<NumType: DoubleRepresentable, Labels: MetricLabels>: Prom
     ///     - labels: Labels to get the value for
     ///
     /// - Returns: The value of the Gauge attached to the provided labels
-    public func get(_ labels: Labels? = nil) -> NumType {
+    public func get(_ labels: DimensionLabels? = nil) -> NumType {
         return self.lock.withLock {
             if let labels = labels {
                 return self.metrics[labels] ?? initialValue

Sources/Prometheus/MetricTypes/Histogram.swift

@@ -63,24 +63,10 @@ public struct Buckets: ExpressibleByArrayLiteral {
     }
 }
 
-/// Label type Histograms can use
-public protocol HistogramLabels: MetricLabels {
-    /// Bucket
-    var le: String { get set }
-}
-
-extension HistogramLabels {
-    /// Creates empty HistogramLabels
-    init() {
-        self.init()
-        self.le = ""
-    }
-}
-
 /// Prometheus Histogram metric
 ///
 /// See https://prometheus.io/docs/concepts/metric_types/#Histogram
-public class PromHistogram<NumType: DoubleRepresentable, Labels: HistogramLabels>: PromMetric, PrometheusHandled {
+public class PromHistogram<NumType: DoubleRepresentable>: PromMetric, PrometheusHandled {
     /// Prometheus instance that created this Histogram
     internal weak var prometheus: PrometheusClient?
 
@@ -93,19 +79,16 @@ public class PromHistogram<NumType: DoubleRepresentable, Labels: HistogramLabels
     public let _type: PromMetricType = .histogram
 
     /// Bucketed values for this Histogram
-    private var buckets: [PromCounter<NumType, EmptyLabels>] = []
+    private var buckets: [PromCounter<NumType>] = []
 
     /// Buckets used by this Histogram
     internal let upperBounds: [Double]
 
-    /// Labels for this Histogram
-    internal let labels: Labels
-
     /// Sub Histograms for this Histogram
-    fileprivate var subHistograms: [Labels: PromHistogram<NumType, Labels>] = [:]
+    fileprivate var subHistograms: [DimensionLabels: PromHistogram<NumType>] = [:]
 
     /// Total value of the Histogram
-    private let sum: PromCounter<NumType, EmptyLabels>
+    private let sum: PromCounter<NumType>
 
     /// Lock used for thread safety
     private let lock: Lock
@@ -115,19 +98,16 @@ public class PromHistogram<NumType: DoubleRepresentable, Labels: HistogramLabels
     /// - Parameters:
     ///     - name: Name of the Histogram
     ///     - help: Help text of the Histogram
-    ///     - labels: Labels for the Histogram
     ///     - buckets: Buckets to use for the Histogram
     ///     - p: Prometheus instance creating this Histogram
-    internal init(_ name: String, _ help: String? = nil, _ labels: Labels = Labels(), _ buckets: Buckets = .defaultBuckets, _ p: PrometheusClient) {
+    internal init(_ name: String, _ help: String? = nil, _ buckets: Buckets = .defaultBuckets, _ p: PrometheusClient) {
         self.name = name
         self.help = help
 
         self.prometheus = p
 
         self.sum = .init("\(self.name)_sum", nil, 0, p)
 
-        self.labels = labels
-
         self.upperBounds = buckets.buckets
 
         self.lock = Lock()
@@ -142,8 +122,8 @@ public class PromHistogram<NumType: DoubleRepresentable, Labels: HistogramLabels
     /// - Returns:
     ///     Newline separated Prometheus formatted metric string
     public func collect() -> String {
-        let (buckets, subHistograms, labels) = self.lock.withLock {
-            (self.buckets, self.subHistograms, self.labels)
+        let (buckets, subHistograms) = self.lock.withLock {
+            (self.buckets, self.subHistograms)
         }
 
         var output = [String]()
@@ -157,13 +137,13 @@ public class PromHistogram<NumType: DoubleRepresentable, Labels: HistogramLabels
         collectBuckets(buckets: buckets,
                        upperBounds: self.upperBounds,
                        name: self.name,
-                       labels: labels,
+                       labels: nil,
                        sum: self.sum.get(),
                        into: &output)
 
         subHistograms.forEach { subHistogram in
             let (subHistogramBuckets, subHistogramLabels) = self.lock.withLock {
-                (subHistogram.value.buckets, subHistogram.value.labels)
+                (subHistogram.value.buckets, subHistogram.key)
             }
             collectBuckets(buckets: subHistogramBuckets,
                            upperBounds: subHistogram.value.upperBounds,
@@ -175,22 +155,20 @@ public class PromHistogram<NumType: DoubleRepresentable, Labels: HistogramLabels
         return output.joined(separator: "\n")
     }
 
-    private func collectBuckets(buckets: [PromCounter<NumType, EmptyLabels>],
+    private func collectBuckets(buckets: [PromCounter<NumType>],
                                 upperBounds: [Double],
                                 name: String,
-                                labels: Labels,
+                                labels: DimensionLabels?,
                                 sum: NumType,
                                 into output: inout [String]) {
-        var labels = labels
         var acc: NumType = 0
         for (i, bound) in upperBounds.enumerated() {
             acc += buckets[i].get()
-            labels.le = bound.description
-            let labelsString = encodeLabels(labels)
+            let labelsString = encodeLabels(EncodableHistogramLabels(labels: labels, le: bound.description))
             output.append("\(name)_bucket\(labelsString) \(acc)")
         }
 
-        let labelsString = encodeLabels(labels, ["le"])
+        let labelsString = encodeLabels(EncodableHistogramLabels(labels: labels))
         output.append("\(name)_count\(labelsString) \(acc)")
 
         output.append("\(name)_sum\(labelsString) \(sum)")
@@ -201,8 +179,8 @@ public class PromHistogram<NumType: DoubleRepresentable, Labels: HistogramLabels
     /// - Parameters:
     ///     - value: Value to observe
     ///     - labels: Labels to attach to the observed value
-    public func observe(_ value: NumType, _ labels: Labels? = nil) {
-        if let labels = labels, type(of: labels) != type(of: EmptyHistogramLabels()) {
+    public func observe(_ value: NumType, _ labels: DimensionLabels? = nil) {
+        if let labels = labels {
             self.getOrCreateHistogram(with: labels)
                 .observe(value)
         }
@@ -222,7 +200,7 @@ public class PromHistogram<NumType: DoubleRepresentable, Labels: HistogramLabels
     ///     - labels: Labels to attach to the resulting value.
     ///     - body: Closure to run & record.
     @inlinable
-    public func time<T>(_ labels: Labels? = nil, _ body: @escaping () throws -> T) rethrows -> T {
+    public func time<T>(_ labels: DimensionLabels? = nil, _ body: @escaping () throws -> T) rethrows -> T {
         let start = DispatchTime.now().uptimeNanoseconds
         defer {
             let delta = Double(DispatchTime.now().uptimeNanoseconds - start)
@@ -232,7 +210,7 @@ public class PromHistogram<NumType: DoubleRepresentable, Labels: HistogramLabels
     }
 
     /// Helper for histograms & labels
-    fileprivate func getOrCreateHistogram(with labels: Labels) -> PromHistogram<NumType, Labels> {
+    fileprivate func getOrCreateHistogram(with labels: DimensionLabels) -> PromHistogram<NumType> {
         let subHistograms = lock.withLock { self.subHistograms }
         if let histogram = subHistograms[labels] {
             precondition(histogram.name == self.name,
@@ -262,7 +240,7 @@ public class PromHistogram<NumType: DoubleRepresentable, Labels: HistogramLabels
                     return histogram
                 }
                 guard let prometheus = prometheus else { fatalError("Lingering Histogram") }
-                let newHistogram = PromHistogram(self.name, self.help, labels, Buckets(self.upperBounds), prometheus)
+                let newHistogram = PromHistogram(self.name, self.help, Buckets(self.upperBounds), prometheus)
                 self.subHistograms[labels] = newHistogram
                 return newHistogram
             }

Sources/Prometheus/MetricTypes/PromMetric.swift

@@ -50,25 +50,3 @@ internal protocol PrometheusHandled {
     /// Prometheus client handling this metric
     var prometheus: PrometheusClient? { get }
 }
-
-/// Base MetricLabels protocol
-///
-/// MetricLabels are used to enrich & specify metrics.
-///
-///     struct Labels: MetricLabels {
-///         let status: String = "unknown"
-///     }
-///     let counter = myProm.createCounter(...)
-///     counter.inc(12, labels: Labels(status: "failure")
-///     counter.inc(1, labels: Labels(status: "success")
-/// Will result in the following Prometheus output:
-///
-///     # TYPE my_counter counter
-///     my_counter 0
-///     my_counter{status="unknown"} 0
-///     my_counter{status="failure"} 12
-///     my_counter{status="success"} 1
-public protocol MetricLabels: Encodable, Hashable {
-    /// Create empty labels
-    init()
-}