New line in reporter (#43)

* fix collection to strign

* make collection into string consistent with collection into buffer

Author: avolokhov

Sources/Prometheus/Prometheus.swift

@@ -36,7 +36,7 @@ public class PrometheusClient {
     ///     - succeed: Closure that will be called with a newline separated string with metrics for all Metrics this PrometheusClient handles
     public func collect(_ succeed: (String) -> ()) {
         self.lock.withLock {
-            succeed(self.metrics.map { $0.collect() }.joined(separator: "\n"))
+            succeed(self.metrics.isEmpty ? "": "\(self.metrics.map { $0.collect() }.joined(separator: "\n"))\n")
         }
     }
 

Tests/SwiftPrometheusTests/GaugeTests.swift

@@ -49,7 +49,7 @@ final class GaugeTests: XCTestCase {
         XCTAssertEqual(try! promise.futureResult.wait(), """
         # TYPE my_gauge gauge
         my_gauge 20.0
-        my_gauge{myValue=\"labels\"} 10.0
+        my_gauge{myValue=\"labels\"} 10.0\n
         """)
     }
 

Tests/SwiftPrometheusTests/HistogramTests.swift

@@ -75,7 +75,7 @@ final class HistogramTests: XCTestCase {
         my_histogram_bucket{myValue="labels", le="10.0"} 1.0
         my_histogram_bucket{myValue="labels", le="+Inf"} 1.0
         my_histogram_count{myValue="labels"} 1.0
-        my_histogram_sum{myValue="labels"} 3.0
+        my_histogram_sum{myValue="labels"} 3.0\n
         """)
     }
 

Tests/SwiftPrometheusTests/PrometheusMetricsTests.swift

@@ -34,7 +34,7 @@ final class PrometheusMetricsTests: XCTestCase {
         XCTAssertEqual(try! promise.futureResult.wait(), """
         # TYPE my_counter counter
         my_counter 10
-        my_counter{myValue=\"labels\"} 10
+        my_counter{myValue=\"labels\"} 10\n
         """)
     }
 
@@ -65,7 +65,44 @@ final class PrometheusMetricsTests: XCTestCase {
         """)
     }
 
-    func testCollectAFewMetricsIntoBuffer() {
+    func testEmptyCollectIsConsistent() throws {
+        let promise = self.eventLoop.makePromise(of: ByteBuffer.self)
+        prom.collect(promise.succeed)
+        var buffer = try promise.futureResult.wait()
+
+        let stringPromise = self.eventLoop.makePromise(of: String.self)
+        prom.collect(stringPromise.succeed)
+        let collectedToString = try stringPromise.futureResult.wait()
+
+        let collectedToBuffer = buffer.readString(length: buffer.readableBytes)
+        XCTAssertEqual(collectedToBuffer, "")
+        XCTAssertEqual(collectedToBuffer, collectedToString)
+    }
+
+    func testCollectIsConsistent() throws {
+        let counter = Counter(label: "my_counter")
+        counter.increment(by: 10)
+        let counterTwo = Counter(label: "my_counter", dimensions: [("myValue", "labels")])
+        counterTwo.increment(by: 10)
+
+        let promise = self.eventLoop.makePromise(of: ByteBuffer.self)
+        prom.collect(promise.succeed)
+        var buffer = try promise.futureResult.wait()
+
+        let stringPromise = self.eventLoop.makePromise(of: String.self)
+        prom.collect(stringPromise.succeed)
+        let collectedToString = try stringPromise.futureResult.wait()
+
+        let collectedToBuffer = buffer.readString(length: buffer.readableBytes)
+        XCTAssertEqual(collectedToBuffer, """
+        # TYPE my_counter counter
+        my_counter 10
+        my_counter{myValue=\"labels\"} 10\n
+        """)
+        XCTAssertEqual(collectedToBuffer, collectedToString)
+    }
+
+    func testCollectAFewMetricsIntoBuffer() throws {
         let counter = Counter(label: "my_counter")
         counter.increment(by: 10)
         let counterA = Counter(label: "my_counter", dimensions: [("a", "aaa"), ("x", "x")])
@@ -75,7 +112,7 @@ final class PrometheusMetricsTests: XCTestCase {
 
         let promise = self.eventLoop.makePromise(of: ByteBuffer.self)
         prom.collect(promise.succeed)
-        var buffer = try! promise.futureResult.wait()
+        var buffer = try promise.futureResult.wait()
 
         XCTAssertEqual(buffer.readString(length: buffer.readableBytes),
             """
@@ -105,8 +142,7 @@ final class PrometheusMetricsTests: XCTestCase {
             my_counter 10
             my_counter{x="x", a="aaa"} 4
             # TYPE my_gauge gauge
-            my_gauge 100.0
+            my_gauge 100.0\n
             """)
     }
 }
-

Tests/SwiftPrometheusTests/SanitizerTests.swift

@@ -46,7 +46,7 @@ final class SanitizerTests: XCTestCase {
         prom.collect(into: promise)
         XCTAssertEqual(try! promise.futureResult.wait(), """
         # TYPE test_counter counter
-        test_counter 10
+        test_counter 10\n
         """)
     }
 }

Tests/SwiftPrometheusTests/SummaryTests.swift

@@ -67,7 +67,7 @@ final class SummaryTests: XCTestCase {
         my_summary{quantile="0.99", myValue="labels"} 123.0
         my_summary{quantile="0.999", myValue="labels"} 123.0
         my_summary_count{myValue="labels"} 1
-        my_summary_sum{myValue="labels"} 123.0
+        my_summary_sum{myValue="labels"} 123.0\n
         """)
     }
 
@@ -93,7 +93,7 @@ final class SummaryTests: XCTestCase {
         my_summary{quantile="0.99"} 10000.0
         my_summary{quantile="0.999"} 10000.0
         my_summary_count 5
-        my_summary_sum 10010.0
+        my_summary_sum 10010.0\n
         """)
     }
 

Tests/SwiftPrometheusTests/SwiftPrometheusTests.swift

@@ -49,7 +49,7 @@ final class SwiftPrometheusTests: XCTestCase {
 
         XCTAssertEqual(counter.collect(), "# HELP my_counter Counter for testing\n# TYPE my_counter counter\nmy_counter 30\nmy_counter{myValue=\"labels\"} 30")
         self.prom.collect { metricsString in
-            XCTAssertEqual(metricsString, "# HELP my_counter Counter for testing\n# TYPE my_counter counter\nmy_counter 30\nmy_counter{myValue=\"labels\"} 30")
+            XCTAssertEqual(metricsString, "# HELP my_counter Counter for testing\n# TYPE my_counter counter\nmy_counter 30\nmy_counter{myValue=\"labels\"} 30\n")
         }
     }
 }