上一篇博文介绍了如何连接Windows Azure: http://www.cnblogs.com/teld/p/5113063.html
本篇我们继续上次的示例代码，获取虚拟机的监控定义和监控数据。
有人会问，Azure Portal上已经有了监控数据，通过代码获取有意思吗？我们计划基于性能计数器的监控数据来实现应用的自动伸缩，因此可以获取到监控指标定义和监控数据应该是第一步。
在Azure的管理Portal中我们可以看到虚拟机的监控数据，目前，提供的主要有以下监控指标：
CPU Percentage；Disk Read; Disk Write; Network in；NetWork Out。
Azure中监控的Nuget主要是这个：Microsoft Azure Management Libraries
核心的几个namespace有：
我们本篇用的是Metric这个命名空间，核心类MetricClient：
namespace AzureTest {using Microsoft.WindowsAzure;using Microsoft.WindowsAzure.Management.Monitoring.Metrics;using Microsoft.WindowsAzure.Management.Monitoring.Metrics.Models;using Microsoft.WindowsAzure.Management.Monitoring.Utilities;/// <summary>/// 监控客户端/// </summary>class MonitorClient{private SubscriptionCloudCredentials credentials;public MonitorClient(SubscriptionCloudCredentials credentials){this.credentials = credentials;}/// <summary>/// 获取所有的监控指标/// </summary>public void GetMetricDefinitions(){var metricsClient = new MetricsClient(credentials);// Build the resource ID string.var resourceId = ResourceIdBuilder.BuildVirtualMachineResourceId("cloudServiceName", "deploymentName");Console.WriteLine("Resource Id: {0}", resourceId);//Get the metric definitions.var metricListResponse=metricsClient.MetricDefinitions.List(resourceId, null, null);34 MetricDefinitionCollection metricDefinitions = metricListResponse.MetricDefinitionCollection; // Display the metric definitions.int count = 0;foreach (MetricDefinition metricDefinition in metricDefinitions.Value){Console.WriteLine("MetricDefinitio: " + count++);Console.WriteLine("Display Name: " + metricDefinition.DisplayName);Console.WriteLine("Metric Name: " + metricDefinition.Name); Console.WriteLine("Metric Namespace: " + metricDefinition.Namespace); Console.WriteLine("Is Altertable: " + metricDefinition.IsAlertable);Console.WriteLine("Min. Altertable Time Window: " + metricDefinition.MinimumAlertableTimeWindow);Console.WriteLine();}} } }
使用上一篇我们的Azure 凭据验证器，获取一个令牌凭据TokenCloudCredentials，然后构造一个MonitorClient，获取指定虚拟机的监控数据。
static void Main(string[] args) { var credential = Authorizator.GetCredentials();var client = new MonitorClient(credential);client.GetMetricDefinitions();Console.ReadLine(); }
第一块代码中：
var resourceId = ResourceIdBuilder.BuildVirtualMachineResourceId("cloudServiceName", "deploymentName");
这个地方通ResourceIDBuilder获取虚拟机的资源ID，对应的参数分别为：cloudServiceName和deploymentName，第一个是虚拟机使用的云服务名称，第二个是虚拟机名称即可。
Run...
出错了：
{"ForbiddenError: The server failed to authenticate the request. Verify that the certificate is valid and is associated with this subscription."}
一番Google后未果，咋整，再分析下错误信息：
可以看到，请求的Uri：
{https://management.core.windows.net/37*****-5107-*****-*******6/services/monitoring/metricdefinitions/query?&resourceId=%2Fhostedservices%2Fteldptapp%2Fdeployments%2Fteldptapp}
请求又跑到Azure Global那去了。
这个错误困扰了好久，还在StackOverflow上发了英文咨询贴，不知道洋人们如何回答了。在此多谢鞠强老大的指导，想办法将请求的Uri定位到中国区的Azure。
重新分析了代码，找到了Monitor的构造函数中，可以指定Uri，将中国区Azure的Uri指定一下：https://management.core.chinacloudapi.cn
MetricsClient metricsClient = new MetricsClient(credentials, new Uri("https://management.core.chinacloudapi.cn/"));
测试通过，ok。
获取到了监控指标定义，接下来我们获取监控数据：
namespace AzureTest {using Microsoft.WindowsAzure;using Microsoft.WindowsAzure.Management.Monitoring.Metrics;using Microsoft.WindowsAzure.Management.Monitoring.Metrics.Models;using Microsoft.WindowsAzure.Management.Monitoring.Utilities;/// <summary>/// 监控客户端/// </summary>class MonitorClient{private SubscriptionCloudCredentials credentials;public MonitorClient(SubscriptionCloudCredentials credentials){this.credentials = credentials;}/// <summary>/// 获取所有的监控指标数据/// </summary>public void GetMetricData(){var metricsClient = new MetricsClient(credentials, new Uri("https://management.core.chinacloudapi.cn/"));// Build the resource ID string.var resourceId = ResourceIdBuilder.BuildVirtualMachineResourceId("cloudServiceName", "deploymentName");Console.WriteLine("Resource Id: {0}", resourceId);//Get the metric definitions.var metricListResponse = metricsClient.MetricDefinitions.List(resourceId, null, null);MetricDefinitionCollection metricDefinitions = metricListResponse.MetricDefinitionCollection;var metricNamespace = "";var metricNames = new List<string>();// Display the metric definitions.int count = 0;foreach (MetricDefinition metricDefinition in metricDefinitions.Value){Console.WriteLine("MetricDefinitio: " + count++);Console.WriteLine("Display Name: " + metricDefinition.DisplayName);Console.WriteLine("Metric Name: " + metricDefinition.Name);if (!metricNames.Contains(metricDefinition.Name))metricNames.Add(metricDefinition.Name);Console.WriteLine("Metric Namespace: " + metricDefinition.Namespace);metricNamespace = metricDefinition.Namespace;Console.WriteLine("Is Altertable: " + metricDefinition.IsAlertable);Console.WriteLine("Min. Altertable Time Window: " + metricDefinition.MinimumAlertableTimeWindow);Console.WriteLine();}// timeGrain must be 5, 60 or 720 minutes.TimeSpan timeGrain = TimeSpan.FromMinutes(5);DateTime startTime = DateTime.UtcNow.AddHours(-1);DateTime endTime = DateTime.UtcNow;MetricValueListResponse response = metricsClient.MetricValues.List(resourceId, metricNames, metricNamespace, timeGrain, startTime, endTime);foreach (MetricValueSet value in response.MetricValueSetCollection.Value){String valueName = value.Name;Console.WriteLine("MetricValue:{0}", valueName);foreach (MetricValue metricValue in value.MetricValues){Console.WriteLine("Maximum:{0}{1}", metricValue.Maximum, value.Unit);Console.WriteLine("Average:{0}{1}", metricValue.Average, value.Unit);Console.WriteLine("Minimum:{0}{1}", metricValue.Minimum, value.Unit);}}}} }
Run...
程序在metricsClient.MetricValues.List(resourceId, metricNames, metricNamespace, timeGrain, startTime, endTime);
出错了：
Additional information: <string xmlns="http://schemas.microsoft.com/2003/10/Serialization/">{"Code":"InvalidRequest","Message":"Could not retrieve metrics."}</string>
为啥不能获取监控指标呢？
这个错误，Google一番依旧未果，咨询了微软的技术工程师，给了如下指导，resouceID必须执行RoleName：
var resourceId = ResourceIdBuilder.BuildVirtualMachineResourceId("cloudService", "deploymentName", "roleName");
修改之后，问题解决。
至此，我们已经可以获取到监控指标和监控数据，下一步我们要获取自定义的性能计数器，基于自定义的性能计数器来实现自动伸缩。
周国庆
2016/3