This function monitors the calls of external services by the current application. It covers CSEConsumer, ApacheHttpClient, ApacheHttpAsyncClient, DubboConsumer, and HttpClient monitoring.

This section focuses on HttpClient monitoring.

Going to the Call Page

Log in to the management console.
Click on the left and choose Management & Deployment > Application Performance Management.
In the navigation pane, choose Application Monitoring > Metrics.
In the tree on the left, click next to the target environment.
Click the Call tab. By default, the HttpClient monitoring information of all instances is displayed.

Figure 1 External call data
On the displayed Call tab page, select a target instance and monitoring item to view the monitoring data in different metric sets.
Figure 2 Selecting an instance and monitoring item
Select a time range. Default: Last 20 minutes.
Options: Last 20 minutes, Last hour, Last 3 hours, Last 6 hours, Last day, Today, Yesterday, Last week, Last month, or Custom.

Figure 3 Selecting a time range
Click in the upper right corner of the list and select the metric data you want to view.

Viewing HttpClient Monitoring Data

URL summary

The HttpClient monitoring system collects the metrics of each URL. For details about the metrics, see Table 1. Click in the upper right corner of the list and select the metric data you want to view.

Figure 4 URL summary under HttpClient monitoring
Click to enlarge

**Table 1** Parameters of URL summary under HttpClient monitoring
Metric Set	Metric	Description
URL summary	url	Called URL
	method	HTTP method of the URL
	Calls	Number of times that the URL is called
	Avg RT (ms)	Average response time of the called URL
	Errors	Number of call errors of the URL
	Max Concurrency	Maximum concurrency of the URL
	Max RT (ms)	Maximum response time of the called URL
	0 ms–10 ms	Number of requests with 0 ms–10 ms response time
	10 ms–100 ms	Number of requests with 10 ms–100 ms response time
	100 ms–500 ms	Number of requests with 100 ms–500 ms response time
	500 ms–1s	Number of requests with 500 ms–1s response time
	1s–10s	Number of requests with 1s–10s response time
	10s–n	Number of requests with response time longer than 10s
	Error Trace	ID of the trace that encounters an error in a collection period
	Slowest Trace	ID of the slowest trace in a collection period

Click a number in blue (such as those in the Calls or Avg RT (ms) column) to view more details.
Click the text in blue (such as those in the Slowest Trace or Error Trace column) to view more details.

Cluster summary

APM can summarize external call metrics by cluster. For details about the metrics, see Table 2.

Figure 5 Cluster summary under HttpClient monitoring
Click to enlarge

**Table 2** Parameters of cluster summary under HttpClient monitoring
Metric Set	Metric	Description
Cluster summary	envId	Cluster ID of the called party
	Calls	Number of times that the cluster URL is called
	Avg RT (ms)	Average response time for calling the cluster URL
	Errors	Number of call errors of the URL
	Max RT (ms)	Maximum response time for calling the cluster URL
	hostUri	URI of the host
	0 ms–10 ms	Number of requests with 0 ms–10 ms response time
	10 ms–100 ms	Number of requests with 10 ms–100 ms response time
	100 ms–500 ms	Number of requests with 100 ms–500 ms response time
	500 ms–1s	Number of requests with 500 ms–1s response time
	1s–10s	Number of requests with 1s–10s response time
	10s–n	Number of requests with response time longer than 10s

Click a number in blue (such as those in the Calls or Avg RT (ms) column) to view more details.

Status code summary

APM can summarize external call metrics by status code. For details about the metrics, see Table 3.

Figure 6 Status code summary under HttpClient monitoring
Click to enlarge

**Table 3** Parameters of status code summary under HttpClient monitoring
Metric Set	Metric	Description
Status code summary	code	Status code
	Count	Number of times that the status code has occurred
	Latest URL	URL that returns the status code

Click a status code in the code column. The tracing page is displayed, showing the invocation condition of the status code of the selected instance in the environment in last 20 minutes (default).
Click a number in the Count column to view the trend of the status code in a specified period.
Click the latest URL to view the invocation details of the corresponding status code.

Exception

On the Exception tab page, view the exception statistics about HttpClient calls. For details about the metrics, see Table 4.

Figure 7 HttpClient monitoring exceptions
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**Table 4** Parameters of HttpClient monitoring exceptions
Metric Set	Metric	Description
Exception	causeType	Exception class
	exceptionType	Exception type
	Count	Number of times the exception has occurred
	Error Message	Message returned when the exception has occurred
	Error Stack	Exception stack information

Click a number in blue in the Count column to view the trend of the thread in a specified period.
Click the text in blue in the Error Message column to view message details.
Click Detail in the Error Stack column to view exception details.
Click History in the Error Stack column to view the historical error stack list.

Overview

On the Overview tab page, view the metrics of the selected instance. For details about the metrics, see Table 5.

Figure 8 Overview under HttpClient monitoring
Click to enlarge

**Table 5** Overview parameters of HttpClient monitoring
Metric Set	Metric	Description
Overview	Calls	Total number of calls
	Avg RT (ms)	Average response time
	Errors	Total number of errors