Best practice integrating Media Pull

To ensure reliability of Media Pull, follow the advice on this page when integrating Media Pull RESTful APIs.

Prerequisites

You need the following to start using Media Pull RESTful API:

The scene of the channel is live, profile set to BROADCASTING
Media Pull is enabled
Message Notification Service is enabled to monitor Media Pull events

Limitations

You are limited in the number of queries per second and concurrent tasks for Media Pull

QPS

The following table shows the limits the number of queries per second (QPS) to the Media Pull RESTful API.

API	QPS limit
Create	Creating cloud players with names is limited to 2 queries per second. Creating cloud players without names is limited to 50 queries per second.
Delete	Deleting cloud players is limited to 100 queries per second.
List	For a project with filter, the limit of the query rate is 2 times per second and 15 times per minute. When there is no filter, the limit of query rate is 10 times per second and 20 times per minute.

When the QPS is exceeded, the status code 429 (Too Many Requests) is returned. If you need a higher QPS limit, contact technical support.

Maximum number of concurrent tasks

The default maximum number of concurrent tasks is 50, which indicates that a maximum of 50 Media Pull tasks can be run simultaneously in one project. If a higher quota is required, contact technical support.

Ensure the high availability of REST services

To ensure the high availability of REST services and prevent downtime caused by regional network faults, Agora provides failover and domain name switch.

Failover

Network failures and risks may be caused by cloud and network software, infrastructure, and other factors that Agora cannot control. To provide the best possible user experience, Media Pull provides high availability automatic task migration for failure recovery. After a failure is confirmed, the Media Pull task is migrated within 240 seconds. During this period, the task may be interrupted.

If you cannot accept the impact of high availability migration based on your own business characteristics, adopt higher quality assurance measures. For example, create multiple Media Pull tasks for critical scenes. Alternatively, you can make periodic API calls and monitor notifications to get the latest task status, then create a new task with a different UID once you confirm the task status is unhealthy.

Multiple Media Pull tasks

If you need a more reliable solution than fault recovery, use multiple Media Pull tasks.

Start a master Media Pull task and multiple backup tasks at the same time, then publish their streams into the same channel. In your app, subscribe audience members to the master stream and listen to the following callback events:

onUserOffline - The callback saying that the anchor is offline
onRemoteAudioStateChanged/onRemoteVideoStateChanged - The host audio and callback state has changed

When you receive these notification, notify the apps where users are subscribed to the channel as audience members so that they switch to a backup stream.

When you create multiple Media Pull tasks, you are charged separately for each of them. For details, see Media Pull pricing.

Switch the domain name

To ensure high availability of REST services, Agora enables you to switch domain names when you experience service outage due to regional network failures. Take the following steps to set up and switch your domain name:

Set the primary domain name based on the location of your service server:
- If the DNS address of the service server is located in a country or region other than mainland China, set the primary domain name to api.agora.io.
- If the DNS address of the service server is in mainland China, set the primary domain name to api.sd-rtn.com.
If your attempt to initiate a RESTful API request using the primary domain fails, set up your retry strategy as follows:
1. Primary domain retry: Retry using the same primary domain name.
2. Alternate domain retry:
  - If the current primary domain name is api.sd-rtn.com, use api.agora.io as the alternate domain name.
  - If the current primary domain name is api.agora.io, use api.sd-rtn.com as the alternate domain name.
3. Adjacent domain retry: If alternate domain retry fails, retry using the domain name adjacent to the current region.
  
  For example, suppose your business server is located in Europe. You set the primary domain name to api.agora.io, and the business server resolves the primary domain name to Germany. Germany is located in central Europe (api-eu-central-1.agora.io). The domain name table shows that the adjacent area is West Europe. Use the api-eu-west-1.agora.io or api-eu-west-1.sd-rtn.com domain name to retry.

Precautions

Take the following precautions when setting up your retry strategy:

To avoid exceeding the QPS limit with retry requests, best practice is to use a back-off strategy. For example, wait 1 second before you retry for the first time, wait 3 seconds before retrying the second time, and wait 6 seconds before retry a third time.
If the request fails because of a network problem rather than a DNS domain name resolution problem, skip alternate domain retry and proceed to adjacent domain retry.
Before switching to the region domain name, ensure that the REST services you wish to use, for example, cloud recording or channel management, are deployed in that region.

Domain name table

The following table shows the primary and region domain names for various regions.

Primary domain name	Region domain name	Region
`api.sd-rtn.com`	`api-us-west-1.sd-rtn.com`	Western United States
	`api-us-east-1.sd-rtn.com`	Eastern United States
	`api-ap-southeast-1.sd-rtn.com`	Southeast Asia Pacific
	`api-ap-northeast-1.sd-rtn.com`	Northeast Asia Pacific
	`api-eu-west-1.sd-rtn.com`	Western Europe
	`api-eu-central-1.sd-rtn.com`	Central Europe
	`api-cn-east-1.sd-rtn.com`	East China
	`api-cn-north-1.sd-rtn.com`	North China
`api.agora.io`	`api-us-west-1.agora.io`	Western United States
	`api-us-east-1.agora.io`	Eastern United States
	`api-ap-southeast-1.agora.io`	Southeast Asia Pacific
	`api-ap-northeast-1.agora.io`	Northeast Asia Pacific
	`api-eu-west-1.agora.io`	Western Europe
	`api-eu-central-1.agora.io`	Central Europe
	`api-cn-east-1.agora.io`	East China
	`api-cn-north-1.agora.io`	North China

Create cloud player

When creating a cloud player with a create API call, pay attention to the following:

Create the cloud player by the region parameter:
- The region you set must be in the same area as your media streaming location. For example, if the media stream source is located in the US, set region to na.
- Pass the region value in lowercase.
Agora recommends that you assign a string value to the X-Request-ID field in the request header. The Agora server returns an X-Custom-request-ID field in the response header for troubleshooting purposes.
Choose to set UID or account as the user name of the cloud player. Do not set these two fields at the same time. Ensure that each cloud player has a unique user name within the channel.
To avoid repeated media streaming due to repeated creation of multiple cloud players, use the name field to manage cloud players under a specific project. Cloud players with the same names cannot exist in the same project. If you attempt to create a cloud player with a name that already exists, you receive the 409 (Conflict) status code.
Note the supported audio and video formats and protocols of the cloud player to avoid media streaming failures caused by unsupported audio and video formats and protocols.
Set an appropriate value for idleTimeout. The default value of 300 seconds is recommended. It means that the cloud player automatically destroys the media stream after 300 seconds.
After listening for a cloud player creation success event, when you successfully create a cloud player, the message notification server notifies your server of the event. The status field in the payload of the event is connecting, indicating that the server is connecting to a media stream address or probing audio and video data.

Query cloud player

Agora recommends that you paginate all cloud player lists under a project as follows:

The query parameter pageToken is not used when List is invoked for the first time. The page query result and nextPageToken returned by the Agora server are obtained in the response message.
When calling List again, pass the nextPageToken value into the query parameter pageToken to query the cloud player list of the next page.

Until nextPageToken is 0, it means that all cloud players under a project have been found. Cloud players are listed in ascending order by creation time (createTs).

Troubleshooting and recommended measures

Retry with retreat strategy

If you receive 404, 429, or 5xx error codes, take an escape strategy. For example, wait 5-6 seconds, 10-11 seconds, or 15-16 seconds and try again. If you get three consecutive 404 or 5xx error codes, or if the state field in the response to checking the status of a media push task says failed, it means that the Media Pull task has failed. To fix this problem, follow these steps:

Check whether the media stream address is correct and whether the media stream can be played.
If the media stream address is correct and can be played, destroy the current cloud player and create a new one.

Troubleshooting by error code

If the status code is 200, the request is successful.
If the status code is not 200, the request has failed. See the error message in the response body for clarification.

Status code	Possible error message	Possible reason of failure	Measures to take
`400` Bad Request	The 'streamUrl' parameter is incorrectly formatted. The `channelName` parameter is invalid. Fix it in your request and retry.	Wrong parameters	Check by referring to the `reason` field in the HTTP response body.
`401` Unauthorized	Invalid authentication credentials.	RESTful API authentication failed.	See RESTful Authentication.
`403` Forbidden	Cloud player is not enabled for this project. Contact us to enable it. This project's permission to use cloud player was revoked. Contact us for details.	The service is not enabled.	Enable the service.
`404` Not Found	Resource is not found or destroyed.	The task was not started or is in the process of failover or deletion.	Retry following the retreat strategy.
`409` Conflict	Resource with the same name already exists.	Resource with the same name already exists.	Delete the existing cloud player and create it again.
`429` Too Many Requests	Request rate limit exceeded. Resource quota exceeded. No available resources.	Too many requests.	Retry following the retreat strategy.
`500` Unknown	Some internal error happened. Contact us to help fix it.	Internal error.	Retry following the retreat strategy.
`502` Bad gateway	Internal errors. Contact us for troubleshooting.	Internal error.	Retry with retreat strategy.
`503` Service Unavailable	Service overload. Retry with the retreat strategy and contact us to help fix it. Service unavailable temporarily. Retry with the retreat strategy.	Internal error	Retry following the retreat strategy.
`504` Gateway Timeout	Gateway timeout. Query to check whether the player has been created or to create one instead.	Internal error.	Retry following the retreat strategy.

Contact Agora technical support

If the error persists, print the X-Request-ID and X-Resource-ID fields in the response header in the log and contact technical support.

Integration checklist

Refer to the following table to quickly check whether each check item meets the integration requirements to ensure the reliability of Media Pull.

Required or optional	Item	Check
Required	Channel mode	Ensure that the scene of the channel is live.
Required	Availability	Enable Media Pull.
Required	QPS limit	Ensure that the rate of API calls in a project is below the maximum limit.
Required	Maximum number of concurrent Tasks	Ensure that the number of concurrent tasks in a project is below 50.
Optional	Cloud player user name	Set UID or account as the user name for cloud player. Do not set both fields at the same time. Use the name field to manage the cloud player under the specified project.
Required	Region	Set the region in the same area as your media streaming. Pass region value in lowercase.
Required	Idle timeout	Set an appropriate `idleTimeout` value. 300 seconds is recommended.
Optional	Troubleshooting	Rectify the errors as follows: Use the retreat strategy. Check the error code. If the preceding troubleshooting methods do not resolve the problem, print the values of the `X-Request-ID` and `X-Resource-ID` fields in the response header and contact Agora technical support.
Optional	Message notifications	Enable message notification service for Media Pull and listen to Media Pull events.