Implement User-Agent spec for transport (#1518)

This commit implements the User-Agent feature.
Update User-Agent sent by the agent to match the spec.
HttpClient parses apm-agent-dotnet/<version> (<service> <version>)
as two separate User-Agent header values:

apm-agent-dotnet/<version>
(<service> <version>)

- Refactor outcome steps to use ScenarioContext.
- Introduce TestConfiguration to allow configuration to be provided a step
at a time.
- Collect all payloads sent to mock HttpMessageHandler.

Co-authored-by: Russ Cam <[email protected]>

src/Elastic.Apm/BackendComm/BackendCommUtils.cs

@@ -193,8 +193,7 @@ internal static HttpClient BuildHttpClient(IApmLogger loggerArg, IConfiguration
 					, serverUrlBase.Sanitize(), dbgCallerDesc);
 			var httpClient =
 				new HttpClient(httpMessageHandler ?? CreateHttpClientHandler(configuration, loggerArg)) { BaseAddress = serverUrlBase };
-			httpClient.DefaultRequestHeaders.UserAgent.Add(
-				new ProductInfoHeaderValue($"elasticapm-{Consts.AgentName}", AdaptUserAgentValue(service.Agent.Version)));
+			httpClient.DefaultRequestHeaders.UserAgent.TryParseAdd(GetUserAgent(service));
 			httpClient.DefaultRequestHeaders.UserAgent.Add(new ProductInfoHeaderValue("System.Net.Http",
 				AdaptUserAgentValue(typeof(HttpClient).Assembly.GetCustomAttribute<AssemblyFileVersionAttribute>().Version)));
 
@@ -213,10 +212,20 @@ internal static HttpClient BuildHttpClient(IApmLogger loggerArg, IConfiguration
 
 			// Replace invalid characters by underscore. All invalid characters can be found at
 			// https://github.com/dotnet/corefx/blob/e64cac6dcacf996f98f0b3f75fb7ad0c12f588f7/src/System.Net.Http/src/System/Net/Http/HttpRuleParser.cs#L41
-			string AdaptUserAgentValue(string value)
+		}
+
+		private static string GetUserAgent(Service service)
+		{
+			var value = $"apm-agent-{Consts.AgentName}/{AdaptUserAgentValue(service.Agent.Version)}";
+			if (!string.IsNullOrEmpty(service.Name))
 			{
-				return Regex.Replace(value, "[ /()<>@,:;={}?\\[\\]\"\\\\]", "_");
+				value += !string.IsNullOrEmpty(service.Version)
+					? $" ({AdaptUserAgentValue(service.Name)} {AdaptUserAgentValue(service.Version)})"
+					: $" ({AdaptUserAgentValue(service.Name)})";
 			}
+			return value;
 		}
+
+		private static string AdaptUserAgentValue(string value) => Regex.Replace(value, "[ /()<>@,:;={}?\\[\\]\"\\\\]", "_");
 	}
 }

test/Elastic.Apm.Feature.Tests/ApiKeySteps.cs

@@ -9,6 +9,7 @@
 namespace Elastic.Apm.Feature.Tests
 {
 	[Binding]
+	[Scope(Feature = "API Key.")]
 	public class ApiKeySteps
 	{
 		private readonly ApiKeyFeatureContext _apiKeyFeatureContext;

test/Elastic.Apm.Feature.Tests/CloudProviderSteps.cs

@@ -3,19 +3,14 @@
 // Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information
 
-using System;
-using System.Collections.Generic;
-using System.IO;
 using System.Net;
 using System.Net.Http;
-using System.Threading;
 using Elastic.Apm.Api;
 using Elastic.Apm.Logging;
 using Elastic.Apm.Report;
 using Elastic.Apm.Tests.Utilities;
 using Elastic.Apm.Tests.Utilities.XUnit;
 using FluentAssertions;
-using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 using RichardSzalay.MockHttp;
 using TechTalk.SpecFlow;
@@ -28,7 +23,7 @@ namespace Elastic.Apm.Feature.Tests
 	[Binding]
 	public class CloudProviderSteps
 	{
-		private static readonly JsonSerializer _serializer = new JsonSerializer();
+
 		private readonly ScenarioContext _scenarioContext;
 
 		public CloudProviderSteps(ScenarioContext scenarioContext) => _scenarioContext = scenarioContext;
@@ -47,13 +42,7 @@ public void AgentWithCloudMetadata(string cloudProvider)
 			handler.When(BuildIntakeV2EventsAbsoluteUrl(config.ServerUrl).AbsoluteUri)
 				.Respond(r =>
 				{
-					var json = r.Content.ReadAsStringAsync().Result;
-					if (json.Contains("\"metadata\""))
-					{
-						payloadCollector.Request = ParseJObjects(json);
-						payloadCollector.WaitHandle.Set();
-					}
-
+					payloadCollector.ProcessPayload(r);
 					return new HttpResponseMessage(HttpStatusCode.OK);
 				});
 
@@ -69,10 +58,7 @@ public void AgentWithCloudMetadata(string cloudProvider)
 					handler,
 					environmentVariables: environmentVariables);
 
-			var lazyAgent = new Lazy<ApmAgent>(() =>
-				new ApmAgent(new TestAgentComponents(logger, config, payloadSender)));
-
-			_scenarioContext.Set(lazyAgent);
+			_scenarioContext.Set(() => new ApmAgent(new TestAgentComponents(logger, config, payloadSender)));
 		}
 
 		[Given("^the following environment variables are present$")]
@@ -87,26 +73,22 @@ public void EnvironmentVariablesSet(Table table)
 		[When("^cloud metadata is collected$")]
 		public void CollectCloudMetadata()
 		{
-			var lazyAgent = _scenarioContext.Get<Lazy<ApmAgent>>();
 			// create the agent and capture a transaction to send metadata
-			var agent = lazyAgent.Value;
+			var agent = _scenarioContext.Get<ApmAgent>();
 			agent.Tracer.CaptureTransaction("Transaction", "feature", () => { });
 
 			var payloadCollector = _scenarioContext.Get<PayloadCollector>();
 
-			// wait for the wait handle to be signalled
-			var timeout = TimeSpan.FromSeconds(30);
-			if (!payloadCollector.WaitHandle.Wait(timeout))
-				throw new Exception($"Did not receive payload within {timeout}");
+			payloadCollector.Wait();
 		}
 
 		[Then("^cloud metadata is not null$")]
 		public void CloudMetadataIsNotNull()
 		{
 			var payloadCollector = _scenarioContext.Get<PayloadCollector>();
 
-			payloadCollector.Request.Should().NotBeNull();
-			var cloudMetadata = payloadCollector.Request[0]["metadata"]["cloud"];
+			payloadCollector.Payloads.Should().NotBeEmpty();
+			var cloudMetadata = payloadCollector.Payloads[0].Body[0]["metadata"]["cloud"];
 			cloudMetadata.Should().NotBeNull();
 		}
 
@@ -115,38 +97,19 @@ public void CloudMetadataIsNull()
 		{
 			var payloadCollector = _scenarioContext.Get<PayloadCollector>();
 
-			payloadCollector.Request.Should().NotBeNull();
-			var cloudMetadata = payloadCollector.Request[0]["metadata"]["cloud"];
+			payloadCollector.Payloads.Should().NotBeEmpty();
+			var cloudMetadata = payloadCollector.Payloads[0].Body[0]["metadata"]["cloud"];
 			cloudMetadata.Should().BeNull();
 		}
 
 		[Then("^cloud metadata '(.*?)' is '(.*?)'$")]
 		public void CloudMetadataKeyEqualsValue(string key, string value)
 		{
 			var payloadCollector = _scenarioContext.Get<PayloadCollector>();
-			var token = payloadCollector.Request[0].SelectToken($"metadata.cloud.{key}");
+			var token = payloadCollector.Payloads[0].Body[0].SelectToken($"metadata.cloud.{key}");
 
 			token.Should().NotBeNull();
 			token.Value<string>().Should().Be(value);
 		}
-
-		private class PayloadCollector
-		{
-			public ManualResetEventSlim WaitHandle { get; }
-
-			public PayloadCollector() => WaitHandle = new ManualResetEventSlim(false);
-
-			public List<JObject> Request { get; set; }
-		}
-
-		private static List<JObject> ParseJObjects(string json)
-		{
-			var jObjects = new List<JObject>();
-			using var stringReader = new StringReader(json);
-			using var jsonReader = new JsonTextReader(stringReader) { SupportMultipleContent = true };
-			while (jsonReader.Read())
-				jObjects.Add(_serializer.Deserialize<JObject>(jsonReader));
-			return jObjects;
-		}
 	}
 }

test/Elastic.Apm.Feature.Tests/ConfigurationSteps.cs

@@ -0,0 +1,37 @@
+// Licensed to Elasticsearch B.V under
+// one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
+using TechTalk.SpecFlow;
+
+namespace Elastic.Apm.Feature.Tests
+{
+	[Binding]
+	public class ConfigurationSteps
+	{
+		private readonly ScenarioContext _scenarioContext;
+
+		public ConfigurationSteps(ScenarioContext scenarioContext) => _scenarioContext = scenarioContext;
+
+		[When("^service name is not set$")]
+		public void WhenServiceNameIsNotSet() { }
+
+		[When("^service version is not set$")]
+		public void WhenServiceVersionIsNotSet() { }
+
+		[When("^service name is set to '(.*?)'$")]
+		public void WhenServiceNameIsSetTo(string name)
+		{
+			var configuration = _scenarioContext.Get<TestConfiguration>();
+			configuration.ServiceName = name;
+		}
+
+		[When("^service version is set to '(.*?)'$")]
+		public void WhenServiceVersionIsSetTo(string version)
+		{
+			var configuration = _scenarioContext.Get<TestConfiguration>();
+			configuration.ServiceVersion = version;
+		}
+	}
+}

test/Elastic.Apm.Feature.Tests/Features/user_agent.feature

@@ -0,0 +1,19 @@
+Feature: Agent Transport User agent Header
+
+  Scenario: Default user-agent
+    Given an agent
+    When service name is not set
+    When service version is not set
+    Then the User-Agent header matches regex '^apm-agent-[a-z]+/[^ ]*'
+
+  Scenario: User-agent with service name only
+    Given an agent
+    When service name is set to 'myService'
+    When service version is not set
+    Then the User-Agent header matches regex '^apm-agent-[a-z]+/[^ ]* \(myService\)'
+
+  Scenario: User-agent with service name and service version
+    Given an agent
+    When service name is set to 'myService'
+    When service version is set to 'v42'
+    Then the User-Agent header matches regex '^apm-agent-[a-z]+/[^ ]* \(myService v42\)'