Centralizes --failure-rate option. Closes #194 (#245)

Author: waldekmastykarz

msgraph-developer-proxy-abstractions/IProxyConfiguration.cs

@@ -0,0 +1,25 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System.Runtime.Serialization;
+
+namespace Microsoft.Graph.DeveloperProxy.Abstractions;
+
+public enum LabelMode {
+    [EnumMember(Value = "text")]
+    Text,
+    [EnumMember(Value = "icon")]
+    Icon,
+    [EnumMember(Value = "nerdFont")]
+    NerdFont
+}
+
+public interface IProxyConfiguration {
+    int Port { get; }
+    LabelMode LabelMode { get; }
+    bool Record { get; }
+    LogLevel LogLevel { get; }
+    IEnumerable<int> WatchPids { get; }
+    IEnumerable<string> WatchProcessNames { get; }
+    int Rate { get; }
+}

msgraph-developer-proxy-abstractions/PluginEvents.cs

@@ -8,7 +8,8 @@
 namespace Microsoft.Graph.DeveloperProxy.Abstractions;
 
 public interface IProxyContext {
-    public ILogger Logger { get; }
+    IProxyConfiguration Configuration { get; }
+    ILogger Logger { get; }
 }
 
 public class ProxyHttpEventArgsBase {

msgraph-developer-proxy-plugins/RandomErrors/GenericRandomErrorPlugin.cs

@@ -19,7 +19,6 @@ internal enum GenericRandomErrorFailMode {
 }
 
 public class GenericRandomErrorConfiguration {
-    public int Rate { get; set; } = 0;
     public string? ErrorsFile { get; set; }
     [JsonPropertyName("responses")]
     public IEnumerable<GenericErrorResponse> Responses { get; set; } = Array.Empty<GenericErrorResponse>();
@@ -28,6 +27,7 @@ public class GenericRandomErrorConfiguration {
 public class GenericRandomErrorPlugin : BaseProxyPlugin {
     private readonly GenericRandomErrorConfiguration _configuration = new();
     private GenericErrorResponsesLoader? _loader = null;
+    private IProxyConfiguration? _proxyConfiguration;
 
     public override string Name => nameof(GenericRandomErrorPlugin);
 
@@ -56,7 +56,7 @@ private GenericRandomErrorFailMode ShouldFail(ProxyRequestArgs e) {
                 _throttledRequests.Remove(key);
             }
         }
-        return _random.Next(1, 100) <= _configuration.Rate ? GenericRandomErrorFailMode.Random : GenericRandomErrorFailMode.PassThru;
+        return _random.Next(1, 100) <= _proxyConfiguration?.Rate ? GenericRandomErrorFailMode.Random : GenericRandomErrorFailMode.PassThru;
     }
 
     private void FailResponse(ProxyRequestArgs e, GenericRandomErrorFailMode failMode) {
@@ -127,6 +127,12 @@ public override void Register(IPluginEvents pluginEvents,
 
         pluginEvents.Init += OnInit;
         pluginEvents.BeforeRequest += OnRequest;
+        
+        // needed to get the failure rate configuration
+        // must keep reference of the whole config rather than just rate
+        // because rate is an int and can be set through command line args
+        // which is done after plugins have been registered
+        _proxyConfiguration = context.Configuration;
     }
 
     private void OnInit(object? sender, InitArgs e) {
@@ -141,7 +147,7 @@ private async Task OnRequest(object? sender, ProxyRequestArgs e) {
             && e.ShouldExecute(_urlsToWatch)) {
             var failMode = ShouldFail(e);
 
-            if (failMode == GenericRandomErrorFailMode.PassThru && _configuration.Rate != 100) {
+            if (failMode == GenericRandomErrorFailMode.PassThru && _proxyConfiguration?.Rate != 100) {
                 _logger?.LogRequest(new[] { "Passed through" }, MessageType.PassedThrough, new LoggingContext(e.Session));
                 return;
             }

msgraph-developer-proxy-plugins/RandomErrors/GraphRandomErrorPlugin.cs

@@ -21,14 +21,13 @@ internal enum GraphRandomErrorFailMode {
 }
 
 public class GraphRandomErrorConfiguration {
-    public int Rate { get; set; } = 0;
     public List<int> AllowedErrors { get; set; } = new();
 }
 
 public class GraphRandomErrorPlugin : BaseProxyPlugin {
-    private readonly Option<int?> _rate;
     private readonly Option<IEnumerable<int>> _allowedErrors;
     private readonly GraphRandomErrorConfiguration _configuration = new();
+    private IProxyConfiguration? _proxyConfiguration;
 
     public override string Name => nameof(GraphRandomErrorPlugin);
 
@@ -89,15 +88,6 @@ public class GraphRandomErrorPlugin : BaseProxyPlugin {
     private readonly Random _random;
 
     public GraphRandomErrorPlugin() {
-        _rate = new Option<int?>("--failure-rate", "The percentage of requests to graph to respond with failures");
-        _rate.AddAlias("-f");
-        _rate.ArgumentHelpName = "failure rate";
-        _rate.AddValidator((input) => {
-            int? value = input.GetValueForOption(_rate);
-            if (value.HasValue && (value < 0 || value > 100)) {
-                input.ErrorMessage = $"{value} is not a valid failure rate. Specify a number between 0 and 100";
-            }
-        });
         _allowedErrors = new Option<IEnumerable<int>>("--allowed-errors", "List of errors that the developer proxy may produce");
         _allowedErrors.AddAlias("-a");
         _allowedErrors.ArgumentHelpName = "allowed errors";
@@ -123,7 +113,7 @@ private GraphRandomErrorFailMode ShouldFail(ProxyRequestArgs e) {
                 _throttledRequests.Remove(key);
             }
         }
-        return _random.Next(1, 100) <= _configuration.Rate ? GraphRandomErrorFailMode.Random : GraphRandomErrorFailMode.PassThru;
+        return _random.Next(1, 100) <= _proxyConfiguration?.Rate ? GraphRandomErrorFailMode.Random : GraphRandomErrorFailMode.PassThru;
     }
 
     private void FailResponse(ProxyRequestArgs e, GraphRandomErrorFailMode failMode) {
@@ -178,19 +168,20 @@ public override void Register(IPluginEvents pluginEvents,
         pluginEvents.Init += OnInit;
         pluginEvents.OptionsLoaded += OnOptionsLoaded;
         pluginEvents.BeforeRequest += OnRequest;
+
+        // needed to get the failure rate configuration
+        // must keep reference of the whole config rather than just rate
+        // because rate is an int and can be set through command line args
+        // which is done after plugins have been registered
+        _proxyConfiguration = context.Configuration;
     }
 
     private void OnInit(object? sender, InitArgs e) {
-        e.RootCommand.AddOption(_rate);
         e.RootCommand.AddOption(_allowedErrors);
     }
 
     private void OnOptionsLoaded(object? sender, OptionsLoadedArgs e) {
         InvocationContext context = e.Context;
-        // configure probability of failure
-        int? rate = context.ParseResult.GetValueForOption(_rate);
-        if (rate.HasValue)
-            _configuration.Rate = rate.Value;
 
         // Configure the allowed errors
         IEnumerable<int>? allowedErrors = context.ParseResult.GetValueForOption(_allowedErrors);
@@ -212,7 +203,7 @@ private async Task OnRequest(object? sender, ProxyRequestArgs e) {
             && e.ShouldExecute(_urlsToWatch)) {
             var failMode = ShouldFail(e);
 
-            if (failMode == GraphRandomErrorFailMode.PassThru && _configuration.Rate != 100) {
+            if (failMode == GraphRandomErrorFailMode.PassThru && _proxyConfiguration?.Rate != 100) {
                 return;
             }
             FailResponse(e, failMode);

msgraph-developer-proxy/Program.cs

@@ -7,7 +7,7 @@
 
 PluginEvents pluginEvents = new PluginEvents();
 ILogger logger = new ConsoleLogger(ProxyCommandHandler.Configuration, pluginEvents);
-IProxyContext context = new ProxyContext(logger);
+IProxyContext context = new ProxyContext(logger, ProxyCommandHandler.Configuration);
 ProxyHost proxyHost = new();
 RootCommand rootCommand = proxyHost.GetRootCommand();
 PluginLoaderResult loaderResults = new PluginLoader(logger).LoadPlugins(pluginEvents, context);

msgraph-developer-proxy/ProxyCommandHandler.cs

@@ -14,6 +14,7 @@ public class ProxyCommandHandler : ICommandHandler {
     public Option<bool?> Record { get; set; }
     public Option<IEnumerable<int>?> WatchPids { get; set; }
     public Option<IEnumerable<string>?> WatchProcessNames { get; set; }
+    public Option<int?> Rate { get; set; }
 
     private readonly PluginEvents _pluginEvents;
     private readonly ISet<UrlToWatch> _urlsToWatch;
@@ -24,6 +25,7 @@ public ProxyCommandHandler(Option<int?> port,
                                Option<bool?> record,
                                Option<IEnumerable<int>?> watchPids,
                                Option<IEnumerable<string>?> watchProcessNames,
+                               Option<int?> rate,
                                PluginEvents pluginEvents,
                                ISet<UrlToWatch> urlsToWatch,
                                ILogger logger) {
@@ -32,6 +34,7 @@ public ProxyCommandHandler(Option<int?> port,
         Record = record ?? throw new ArgumentNullException(nameof(record));
         WatchPids = watchPids ?? throw new ArgumentNullException(nameof(watchPids));
         WatchProcessNames = watchProcessNames ?? throw new ArgumentNullException(nameof(watchProcessNames));
+        Rate = rate ?? throw new ArgumentNullException(nameof(rate));
         _pluginEvents = pluginEvents ?? throw new ArgumentNullException(nameof(pluginEvents));
         _urlsToWatch = urlsToWatch ?? throw new ArgumentNullException(nameof(urlsToWatch));
         _logger = logger ?? throw new ArgumentNullException(nameof(logger));
@@ -62,6 +65,10 @@ public async Task<int> InvokeAsync(InvocationContext context) {
         if (watchProcessNames is not null) {
             Configuration.WatchProcessNames = watchProcessNames;
         }
+        var rate = context.ParseResult.GetValueForOption(Rate);
+        if (rate is not null) {
+            Configuration.Rate = rate.Value;
+        }
 
         CancellationToken? cancellationToken = (CancellationToken?)context.BindingContext.GetService(typeof(CancellationToken?));
 

msgraph-developer-proxy/ProxyConfiguration.cs

@@ -1,22 +1,12 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
-using System.Runtime.Serialization;
 using System.Text.Json.Serialization;
 using Microsoft.Graph.DeveloperProxy.Abstractions;
 
 namespace Microsoft.Graph.DeveloperProxy;
 
-public enum LabelMode {
-    [EnumMember(Value = "text")]
-    Text,
-    [EnumMember(Value = "icon")]
-    Icon,
-    [EnumMember(Value = "nerdFont")]
-    NerdFont
-}
-
-public class ProxyConfiguration {
+public class ProxyConfiguration: IProxyConfiguration {
     [JsonPropertyName("port")]
     public int Port { get; set; } = 8000;
     [JsonPropertyName("labelMode")]
@@ -29,5 +19,7 @@ public class ProxyConfiguration {
     public LogLevel LogLevel { get; set; } = LogLevel.Info;
     public IEnumerable<int> WatchPids { get; set; } = new List<int>();
     public IEnumerable<string> WatchProcessNames { get; set; } = new List<string>();
+    [JsonPropertyName("rate")]
+    public int Rate { get; set; } = 50;
 }
 

msgraph-developer-proxy/ProxyContext.cs

@@ -5,10 +5,15 @@
 
 namespace Microsoft.Graph.DeveloperProxy;
 
-internal class ProxyContext : IProxyContext {
-    public ILogger Logger { get; }
+internal class ProxyContext : IProxyContext
+{
+  public ILogger Logger { get; }
 
-    public ProxyContext(ILogger logger) {
-        Logger = logger ?? throw new ArgumentNullException(nameof(logger));
-    }
+  public IProxyConfiguration Configuration { get; }
+
+  public ProxyContext(ILogger logger, IProxyConfiguration configuration)
+  {
+    Logger = logger ?? throw new ArgumentNullException(nameof(logger));
+    Configuration = configuration ?? throw new ArgumentNullException(nameof(configuration));
+  }
 }

msgraph-developer-proxy/ProxyHost.cs

@@ -14,6 +14,7 @@ internal class ProxyHost {
     private Option<IEnumerable<int>?> _watchPidsOption;
     private Option<IEnumerable<string>?> _watchProcessNamesOption;
     private static Option<string?>? _configFileOption;
+    private Option<int?> _rateOption;
 
     private static bool _configFileResolved = false;
     private static string _configFile = "appsettings.json";
@@ -73,6 +74,16 @@ public ProxyHost() {
         _watchProcessNamesOption = new Option<IEnumerable<string>?>("--watch-process-names", "The names of processes to watch for requests");
         _watchProcessNamesOption.ArgumentHelpName = "processNames";
         _watchProcessNamesOption.AllowMultipleArgumentsPerToken = true;
+
+        _rateOption = new Option<int?>("--failure-rate", "The percentage of chance that a request will fail");
+        _rateOption.AddAlias("-f");
+        _rateOption.ArgumentHelpName = "failure rate";
+        _rateOption.AddValidator((input) => {
+            int? value = input.GetValueForOption(_rateOption);
+            if (value.HasValue && (value < 0 || value > 100)) {
+                input.ErrorMessage = $"{value} is not a valid failure rate. Specify a number between 0 and 100";
+            }
+        });
     }
 
     public RootCommand GetRootCommand() {
@@ -82,6 +93,7 @@ public RootCommand GetRootCommand() {
             _recordOption,
             _watchPidsOption,
             _watchProcessNamesOption,
+            _rateOption,
             // _configFileOption is set during the call to load
             // `ProxyCommandHandler.Configuration`. As such, it's always set here
             _configFileOption!
@@ -91,6 +103,6 @@ public RootCommand GetRootCommand() {
         return command;
     }
 
-    public ProxyCommandHandler GetCommandHandler(PluginEvents pluginEvents, ISet<UrlToWatch> urlsToWatch, ILogger logger) => new ProxyCommandHandler(_portOption, _logLevelOption, _recordOption, _watchPidsOption, _watchProcessNamesOption, pluginEvents, urlsToWatch, logger);
+    public ProxyCommandHandler GetCommandHandler(PluginEvents pluginEvents, ISet<UrlToWatch> urlsToWatch, ILogger logger) => new ProxyCommandHandler(_portOption, _logLevelOption, _recordOption, _watchPidsOption, _watchProcessNamesOption, _rateOption, pluginEvents, urlsToWatch, logger);
 }
 

msgraph-developer-proxy/appsettings.json

@@ -104,12 +104,12 @@
     "mocksFile": "responses.json"
   },
   "graphRandomErrorsPlugin": {
-    "rate": 50,
     "allowedErrors": [ 429, 500, 502, 503, 504, 507 ]
   },
   "executionSummaryPlugin": {
     "groupBy": "url"
   },
+  "rate": 50,
   "labelMode": "text",
   "logLevel": "info"
 }