tencent cloud

Note

If your function was created before January 29, 2021 and has not been migrated, but you want to use more log analysis features, deliver function invocation logs to CLS as instructed in Log Delivery Configuration (Legacy).

SCF was fully connected to Tencent Cloud CLS starting from January 29, 2021. After then, the invocation logs of newly created functions will be delivered to CLS, and logs can be output in real time. The existing functions are gradually migrated by regions. For more information, see SCF Log Service Change Notification.

This document describes the two log delivery methods of default delivery and custom delivery provided by SCF and how to configure them.

Permission Description

To view the logs normally, ensure that the sub-account at least has the read-only permission of CLS QcloudCLSReadOnlyAccess. For how the root account grant permissions for the sub-account, see Authorization Management.

Restrictions

Delivering function invocation logs to CLS has the following limits:

• The maximum amount of logs printed within 5 seconds for each request is 1 MB.
• The maximum number of logs printed within 5 seconds for each request is 5000.
• The maximum length of each log is 8 KB, and excessive parts will be discarded.

Directions

Default delivery

When creating a function, if you don't specify the destination topic for log delivery, the default log delivery capability will be used. For default log delivery, SCF will activate the CLS service for you and deliver the function invocation logs to the log topic under the SCF-specific logset. The SCF-specific logset and log topic are prefixed with SCF_logset and SCF_logtopic respectively, and will be created automatically if they do not exist. Function invocation logs will be retained for 7 days by default, and you can view and manage them on the CLS console.

Note：

• CLS is billed separately, and the SCF-specific log topic will consume the free tier of CLS. For more information, see Billing Overview.
• To ensure the proper display of logs in the SCF console, SCF-specific log topics do not support modifying the log index configuration. To customize the index configuration, configure the function log topic as instructed in Custom delivery below.

Configuring CLS

1. Log in to the SCF console and select Functions on the left sidebar.
2. Select the region and namespace where to create a function at the top of the page and click Create to enter the function creation process.
3. In Log configuration, select Default as shown below:
   
4. Click Complete. You can view the log configuration in Function management > Function configuration as shown below:
   

Viewing and managing logs

You can click the logset ID in Log Configuration in Function Configuration to enter the CLS console to view and manage logs. The SCF-specific logset is marked with the word SCF in the CLS console. If you need to persistently store, deliver, or consume logs or monitor and set alarms on log content, you can complete the configuration in the CLS console.

Custom delivery

When creating a function, if you need to specify the destination log topic to deliver function invocation logs, you can use the custom log delivery capability. Before using this capability, you should make sure that the CLS service has been activated.

Creating logset and log topic

Log in to the CLS console and create a log topic. This document uses the creation of the SCF-test log topic in Guangzhou as an example as shown below:

Note：

For the logset region, select the region where the SCF service is located. Cross-region log push is not supported currently.

Configuring CLS

1. Log in to the SCF console and select Functions on the left sidebar.
2. Select the region where to create a function at the top of the page and click Create to enter the function creation process.
3. In Log configuration, select Custom and select the log topic already created for this function. This document uses SCF-test as an example as shown below:
   
4. Click Confirm.

Configuring indexes

Log search depends on the index configuration of the log topic. SCF will automatically complete the index configuration when you create a function. If the index is abnormal and logs cannot be viewed properly, configure the index in the following steps:

1. Log in to the SCF console and select Functions on the left sidebar.
2. On the Function Service list page, select the name of the function whose index is abnormal to enter the Function Management page.
3. On the Log Query tab, select Index Configuration in Advanced Retrieval as shown below:
   
4. On the Index configuration page, enable Index status and Key-value index as shown below:
   
   This configuration method is only valid for scenarios where there are function invocation logs in the log topic; otherwise, manually configure the key-value index by referring to the table below.

   Field Name	Field Type	Description
   SCF_FunctionName	text	Function name
   SCF_Namespace	text	Function namespace
   SCF_StartTime	long	Invocation start time
   SCF_LogTime	long	Log generation time
   SCF_RequestId	text	Request ID
   SCF_Duration	long	Function execution duration
   SCF_Alias	text	Alias
   SCF_Qualifier	text	Version
   SCF_MemUsage	double	Function runtime memory
   SCF_Level	text	Log4J log level. Default value: INFO
   SCF_Message	text	Log content
   SCF_Type	text	Log type. Platform: Platform log; Custom: User log
   SCF_StatusCode	long	Status code of function execution
   SCF_RetryNum	long	Number of retries

To ensure the display effect of the logs in the SCF console, toggle on Enable Statistics for the field in the key-value index configuration:
5. After configuring the index, click OK.