Debug log mode - AWS Elemental MediaTailor

Debug log mode

Use debug logs to troubleshoot playback session issues. To generate debug logs, set the log mode to debug in the player's request to MediaTailor. For server-side reporting, set the log mode in the playback request. For client-side reporting, set the log mode in the session initialization request.

When the log mode is set to debug, MediaTailor writes the debug log data to CloudWatch Logs. The debug logs provide information about the following events. For a complete list of the data produced in the debug logs, see Debug log fields.

  • Origin interaction – Details about MediaTailor's interaction with the origin server. For example, the origin manifest response, manifest type, and origin URL.

  • Generated manifest – Details about the playback session response from MediaTailor. For example, the manifest that MediaTailor generates.

  • Session initialized – Session initialization details, such as the session ID.

Prerequisites

To set the log mode to debug, first you need to grant MediaTailor permission to send logs to CloudWatch, if you haven't already. Once you've granted permission for MediaTailor to access CloudWatch, then you're ready to enable the debug log mode. For information about how to grant MediaTailor permission to access CloudWatch see Setting Up Permissions for Amazon CloudWatch.

How to set the log mode to debug

This section explains how to set the log mode to debug for server-side reporting and client-side reporting.

Server-side reporting

For server-side reporting, include the ?aws.logMode=DEBUG query parameter and value in your player's GET HTTP playback request to the HLS or DASH MediaTailor endpoint. For general information about server-side reporting see Server-side Reporting.

Important

The DEBUG value is case-sensitive.

A playback request that includes ?aws.logMode=DEBUG looks like the following:

Example Playback request to an HLS endpoint

GET <mediatailorURL>/v1/master/<hashed-account-id>/<origin-id>/<asset-id>?aws.logMode=DEBUG

After you set the log mode to debug, we recommend that you verify that the debug logging session is active. To verify that the debug session is active, check to see if there are any CloudWatch logs for the session ID. The session ID is included in the playback endpoint that MediaTailor provides. For more information, see Verify that the debug log mode is active for your playback session.

Client-side reporting

For client-side reporting, include the logMode key and DEBUG value in your client's POST HTTP session initialization request body to the MediaTailor /v1/session endpoint. For general information about client-side reporting see Client-Side Reporting.

Important

The DEBUG value is case-sensitive.

After you set the log mode to debug, we recommend that you verify that the debug session is active. To verify that the debug session is active, confirm that there's a SESSION_INITIALIZED event associated with the session ID in the CloudWatch logs. The session ID is included in the playback endpoint that MediaTailor provides. For more information, see Verify that the debug log mode is active for your playback session.

Maximum active debug sessions

You can have a maximum of 10 active debug log sessions. When your player sends its session initialization or playback request to MediaTailor, MediaTailor checks to see if the limit has been reached. If it has, MediaTailor checks to see if there are any stale sessions. A session is stale if it hasn't been accessed within a certain period of time. For live streams this time period is 10 minutes, for VOD streams it's 30 minutes.

If the maximum active debug log sessions limit has been reached, debug logs aren't written to CloudWatch Logs for your session. If you don't see debug logs in CloudWatch Logs for your session, you could have reached this limit. To confirm if the limit has been reached, see Verify that the debug log mode is active for your playback session.

Debug log fields

The following table lists the debug log fields that MediaTailor writes to CloudWatch.

Field Description
awsAccountId Your AWS account ID.
customerId Your MediaTailor customer ID.
eventTimestamp The ISO 8601 timestamp associated with the debug log event.
eventType The type of debug log event.

Values:

  • ORIGIN_INTERACTION – Details about MediaTailor's interaction with the origin server. For example, the origin manifest response, manifest type, and origin URL.

  • GENERATED_MANIFEST – Details about the playback session response from MediaTailor. For example, the manifest that MediaTailor generates.

  • SESSION_INITIALIZED – Session initialization details, such as the session ID.

originRequestUrl The URL of your origin server that is retrieved for this request.
mediaTailorPath The MediaTailor endpoint that was called, including any parameters passed to MediaTailor in the initial manifest request.
requestId The ID of a specific HTTP request to MediaTailor.
responseBody The manifest in the response body from MediaTailor. This is either the raw origin manifest or the manifest generated by MediaTailor.
sessionId The playback session ID.
sessionType The type of playback session.

Values: HLS, DASH

Read the debug logs

MediaTailor writes the debug logs to Amazon CloudWatch Logs. Typical CloudWatch Logs charges apply. Use CloudWatch Insights to read the debug logs. For information on how to use CloudWatch Logs Insights, see Analyzing Log Data with CloudWatch Logs Insights in the AWS CloudWatch Logs User Guide.

Note

The debug logs can take a few minutes to appear in CloudWatch. If you don't see the logs, wait a few minutes and try again. If you still don't see the logs, it could be that you've reached the maximum number of active debug log sessions. To verify if this is the case, run a CloudWatch query to see if there was a debug session initialized for your playback session. For more information, see Verify that the debug log mode is active for your playback session.

Examples

This section includes example queries that you can use to read MediaTailor debug log data.

Example 1: Verify that the debug log mode is active for your playback session

fields @timestamp, @message | filter sessionId = "32002de2-837c-4e3e-9660-f3075e8dfd90" | filter eventType = "SESSION_INITIALIZED" # client-side reporting or mediaTailorPath like “/v1/master” # server-side reporting HLS or mediaTailorPath like “/v1/dash” # server-side reporting DASH

Example 2: View the responses from your origin

fields @timestamp, responseBody, @message, mediaTailorPath | filter eventType = "ORIGIN_MANIFEST" and sessionId = "32002de2-837c-4e3e-9660-f3075e8dfd90"

Example 3: View the manifest generated by MediaTailor for a given session

fields @timestamp, responseBody, @message | filter mediaTailorPath like "/v1/master/" and eventType = "GENERATED_MANIFEST" and sessionId = "32002de2-837c-4e3e-9660-f3075e8dfd90"

Example 4: View all events for a given requestId

Use this query to view the origin manifest and the manifest generated by MediaTailor.

fields @timestamp, responseBody, @message, mediaTailorPath | filter requestId = "e5ba82a5-f8ac-4efb-88a0-55bed21c45b4"