putIndexPolicy method

Future<PutIndexPolicyResponse> putIndexPolicy({ required String logGroupIdentifier, required String policyDocument, })

Creates or updates a field index policy for the specified log group. Only log groups in the Standard log class support field index policies. For more information about log classes, see Log classes.

You can use field index policies to create field indexes on fields found in log events in the log group. Creating field indexes speeds up and lowers the costs for CloudWatch Logs Insights queries that reference those field indexes, because these queries attempt to skip the processing of log events that are known to not match the indexed field. Good fields to index are fields that you often need to query for and fields or values that match only a small fraction of the total log events. Common examples of indexes include request ID, session ID, userID, and instance IDs. For more information, see Create field indexes to improve query performance and reduce costs.

You can configure indexed fields as facets to enable interactive exploration and filtering of your logs in the CloudWatch Logs Insights console. Facets allow you to view value distributions and counts for indexed fields without running queries. When you create a field index, you can optionally set it as a facet to enable this interactive analysis capability. For more information, see Use facets to group and explore logs.

To find the fields that are in your log group events, use the GetLogGroupFields operation.

For example, suppose you have created a field index for requestId. Then, any CloudWatch Logs Insights query on that log group that includes requestId = value or requestId IN [value, value, ...] will process fewer log events to reduce costs, and have improved performance.

CloudWatch Logs provides default field indexes for all log groups in the Standard log class. Default field indexes are automatically available for the following fields:

• @logStream
• @aws.region
• @aws.account
• @source.log
• traceId

Default field indexes are in addition to any custom field indexes you define within your policy. Default field indexes are not counted towards your field index quota.

Each index policy has the following quotas and restrictions:

• As many as 20 fields can be included in the policy.
• Each field name can include as many as 100 characters.

Matches of log events to the names of indexed fields are case-sensitive. For example, a field index of RequestId won't match a log event containing requestId.

Log group-level field index policies created with PutIndexPolicy override account-level field index policies created with PutAccountPolicy that apply to log groups. If you use PutIndexPolicy to create a field index policy for a log group, that log group uses only that policy for log group-level indexing, including any facet configurations. The log group ignores any account-wide field index policy that applies to log groups, but data source-based account policies may still apply.

May throw InvalidParameterException. May throw LimitExceededException. May throw OperationAbortedException. May throw ResourceNotFoundException. May throw ServiceUnavailableException.

Parameter logGroupIdentifier : Specify either the log group name or log group ARN to apply this field index policy to. If you specify an ARN, use the format arn:aws:logs:region:account-id:log-group:log_group_name Don't include an * at the end.

Parameter policyDocument : The index policy document, in JSON format. The following is an example of an index policy document that creates indexes with different types.

"policyDocument": "{"Fields": [ "TransactionId" ], "FieldsV2": {"RequestId": {"type": "FIELD_INDEX"}, "APIName": {"type": "FACET"}, "StatusCode": {"type": "FACET"}}}"

You can use FieldsV2 to specify the type for each field. Supported types are FIELD_INDEX and FACET. Field names within Fields and FieldsV2 must be mutually exclusive.

The policy document must include at least one field index. For more information about the fields that can be included and other restrictions, see Field index syntax and quotas.

Implementation

Future<PutIndexPolicyResponse> putIndexPolicy({
  required String logGroupIdentifier,
  required String policyDocument,
}) async {
  final headers = <String, String>{
    'Content-Type': 'application/x-amz-json-1.1',
    'X-Amz-Target': 'Logs_20140328.PutIndexPolicy'
  };
  final jsonResponse = await _protocol.send(
    method: 'POST',
    requestUri: '/',
    exceptionFnMap: _exceptionFns,
    // TODO queryParams
    headers: headers,
    payload: {
      'logGroupIdentifier': logGroupIdentifier,
      'policyDocument': policyDocument,
    },
  );

  return PutIndexPolicyResponse.fromJson(jsonResponse.body);
}