Troubleshooting and tracing

hilog outputs

The SDK provides hilog log outputs. When you develop in a local environment, view the logs in your development tool. The following code provides an example:

import { httpdns } from '@aliyun/httpdns';

httpdns.enableHiLog();

After you enable hilog log outputs, the SDK outputs relevant logs when you call SDK APIs. This helps you check the network request status of the SDK. The following log provides an example:

04-16 00:10:01.201   12063-12063  A08000/100000                  com.aliyu...dns.demo  I     asyncResolve www.aliyun.com 3 begin
04-16 00:10:01.202   12063-12063  A08000/Http                    com.aliyu...dns.demo  I     http://[2401:b180:2000:30::1c]/100000/d?host=www.aliyun.com&query=6&sid=4vkjAaOpeRXn&sdk=harmony_0.0.0 begin
04-16 00:10:01.281   12063-12063  A08000/Http                    com.aliyu...dns.demo  I     http://[2401:b180:2000:30::1c]/100000/d?host=www.aliyun.com&query=6&sid=4vkjAaOpeRXn&sdk=harmony_0.0.0 success {"host":"www.aliyun.com","ttl":30,"origin_ttl":30,"client_ip":"2401:b180:8000:1:e0e3:8b81:e0e3:8b81","ipsv6":["2401:b180:1:60:0:0:0:5","2401:b180:1:60:0:0:0:6"]}
04-16 00:10:01.281   12063-12063  A08000/100000                  com.aliyu...dns.demo  I     asyncResolve www.aliyun.com 3 end {"host":"www.aliyun.com","hasResult":true,"valid":true,"ipv6s":["2401:b180:1:60:0:0:0:5","2401:b180:1:60:0:0:0:6"]}

The URL http://[2401:b180:2000:30::1c]/100000/d?host=www.aliyun.com&query=6&sid=4vkjAaOpeRXn&sdk=harmony_0.0.0 is a request sent by the SDK. For more information about the request protocol, see Resolve a single domain name.

Online log collection

The SDK provides a log registration API that helps you integrate log collection system into your application. The following code provides an example:

import { httpdns, ILogger } from '@aliyun/httpdns';
import hilog from '@ohos.hilog';

class AppLogger implements ILogger {
  log(level: hilog.LogLevel, msg: string): void {
    // Receive logs in the log system.
    // By default, collect logs of hilog.LogLevel.ERROR and higher.
  }
}

const appLogger = new AppLogger();

httpdns.addLogger(appLogger);

In a production environment, we recommend that you collect logs with a level of hilog.LogLevel.ERROR or higher, or use a proactive switch policy to control when to collect logs.

Troubleshoot "RESOLVE FAIL" logs

For SDK 1.2.1 and later, when domain name resolution fails, the SDK prints a log message in the format of "RESOLVE FAIL, Host:xxx, Query:xxx Msg:xxx". You can search for logs that have the "RESOLVE FAIL" prefix to identify the cause of the failure. The following logs provide examples:

Invalid signature:

04-11 11:04:58.443   14509-14509   A08000/100000     com.aliyu...lication  W     RESOLVE FAIL, Host:www.aliyun.com, Query:4 Msg:HTTPDNS_102: InvalidSignature 

Expired signature:

04-11 13:41:20.380   2316-2316   A08000/100000     com.aliyu...ns.demo2  W     RESOLVE FAIL, Host:www.aliyun.com, Query:4,6 Msg:HTTPDNS_102: SignatureExpired 

Network error:

04-11 14:39:57.532   2316-2316   A08000/100000     com.aliyu...ns.demo2  W     RESOLVE FAIL, Host:www.aliyun.com, Query:6 Msg:HTTPDNS_101: Request failed,{"code":2300007,"message":"Couldn't connect to server"} 

Domain name not configured in the console:

04-11 15:53:16.623   23160-23160  A08000/ResolveService      com.aliyu...ns.demo2  W     RESOLVE FAIL, Host:www.aliyun.com, Query:4 Msg:NonWhitelistDomain

In the preceding log, "RESOLVE FAIL, Host:www.aliyun.com, Query:4 Msg:HTTPDNS_102: InvalidSignature" is the resolution failure log message. Host indicates the domain name to resolve. Query indicates the IP address type to resolve. Msg indicates the error message for the failure.

Get the sessionId

Work with the HTTPDNS service team to troubleshoot issues that are difficult to diagnose. The SDK provides a sessionId field. Each time the SDK sends a resolution request to the service, it includes the sessionId. Therefore, when an issue occurs, retrieve the sessionId. This helps the HTTPDNS team find the relevant resolution request. To retrieve the sessionId, perform the following steps:

import { httpdns, HttpDnsError } from '@aliyun/httpdns';
import hilog from '@ohos.hilog';

const ACCOUNT_ID = 'Replace this with the Account ID from the Alibaba Cloud HTTPDNS console';

httpdns.getService(ACCOUNT_ID).then((service) => {
  // ************* Get sessionId: start *************
  const sessionId = service.getSessionId();
  // ************* Get sessionId: end *************
  console.log(`sessionId is ${sessionId}`);
}).catch((e: HttpDnsError) => {
  console.error(`Failed ${e.code} ${e.message}`);
});

If a resolution error occurs, provide this information when you seek technical support through DingTalk groups or tickets.