Baidu Live iOS SDK platform output transformation

Introduction: Baidu Live is positioned as a live broadcast SDK, enabling the use of Baidu's in-house APP. With the rapid expansion of business scale, the expansion of code volume, and the strong demand for host access customization, the live broadcast engineering architecture is also constantly being optimized without affecting business iteration and business scale expansion.

1. Background

Baidu Live is positioned as a live SDK, enabling Baidu's in-house apps. As the business scale rapidly expands and the code volume expands, the original engineering structure of live broadcast restricts the rapid development of live broadcast. As more vertical apps are connected, the host access process is difficult to customize, configuration and debugging is time-consuming, and there are many protocols that need to be implemented, which restricts the external output of the SDK. In summary, there are two major problems:

• Project-level issues: Native project structure affects development efficiency/business code coupling is serious/host-bound function macro definitions make it difficult to differentiate SDK output
• Issues with the access process: Difficult customization/time-consuming configuration and debugging/many protocols, etc.

Without affecting business iteration and business scale expansion, the live broadcast team carried out targeted and gradual transformation to achieve flexible and efficient platform output of the final SDK.

2. Engineering Level Transformation

The transformation at the engineering level is divided into three steps. The first is to connect the project to EasyBox, the second is to split the multi-warehouse into components in the business dimension, and finally improve the SDK's differentiated output capabilities based on the first two steps, completing the overall transformation and migration of the engineering architecture.

1. Engineering transformation

The earliest live broadcast projects were based on Xcode native projects, with multiple projects nested and connected to realize project components. This approach has too many disadvantages. Based on the EasyBox tool chain developed by Sogou, live broadcasts have been transformed into an engineering project. The EasyBox tool chain is a standardized template-based transformation for projects.

First, the LiveBoxAPP project is shelled. Secondly, the original business project standard layering is divided into logical levels for the live broadcast project:

• Shell project, live SDK compilation and operation construction environment
• MixTure build layer, controls SDK differentiation, supports variant component differentiation through EasyBox, and controls the free combination generation of product SDK through link_dependency
• Business layer, live core business
• Basic library layer
• Host platform library dependency layer/third-party dependency library​

Based on the above transformation, the dependency relationship of the live broadcast project is clearer. The Easybox layering prevents the dependencies between layers from being broken. The above transformation is only based on the upgrade of the original live broadcast project structure. The business warehouse itself still has problems, so the business warehouse is split into multiple warehouses and multiple component templates. ​

2. Multi-warehouse and multi-component template splitting

The main problem with the business warehouse is that the business is severely coupled/no isolation of permissions. The early warehouse management mechanism of live broadcast was Monorepo. As the business scale expanded and the team expanded, live broadcast was divided into multiple warehouses according to the template business. The warehouse management was upgraded to Multirepo, and easyBox itself also supports Multirepo mode. The live broadcast room business VC is managed by a slotPage framework to manage layout and services. In simple terms, slotPage divides the UI and capabilities of the live broadcast room into components/plug-ins/services (within the live broadcast room), and provides a set of page management mechanisms for component layout management/event distribution/basic state management. Live broadcast has split the template dimension for the business layer warehouse components, which is specifically divided into the following steps:

• The business layer is split into the service layer, and the common capabilities are unified and transferred to the warehouse components of the service layer
• Split the basic core live broadcast container components to provide core capabilities of the live broadcast room
• Split the live broadcast room function into a common component plug-in pool
• Split the Business layer warehouse components according to the template dimension, and attribute the business template-specific (in the live broadcast room) components/plug-ins​

3. Support SDK differentiated output

Different hosts have very different requirements for SDK customization, so the SDK must flexibly support tailoring. Although EasyBox can achieve differentiated construction through variants and link_dependency, it is not suitable for tailoring and customizing the functions of small components in the live broadcast room. Therefore, live broadcast provides the ability to inject small components at compile time. The live broadcast component contains a registration module, which distributes the Module Event of the live broadcast core. When the event is appropriate, the component service is registered to Pyramid. The separation of impl and interface is adopted to achieve the compilation isolation of components that need differentiated output. Differentiated components are prohibited from horizontal dependencies, and impl components can only depend on interface components.

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Based on the above transformation, the differentiated assembly and construction of live broadcast function widgets are flexibly realized. ​

3. Access efficiency optimization

After the transformation of the engineering level issues was completed, in order to achieve automatic host access/quick debugging, the live broadcast team also made a lot of auxiliary tools to enable automatic access for the business side.

1. Automated access platform

Since SDK functions are complex and optional, and there are many upstream and downstream dependencies, each access to a host involves many businesses, resulting in a particularly high access cost. Therefore, Live has developed a visual packet output platform. The host access is using the access document + independent packet output platform solution to reduce the access cost. The following is a flow chart:

On the access platform, apply for SDK access, fill in the corresponding information, and select functions according to the function list provided by the live broadcast. After the review is passed, the corresponding SDK build will be triggered, and the SDK product can be quickly obtained. According to the access document provided by the live broadcast, automatic access can be achieved.

2. Fast source code debugging/mapping

Live broadcast is a huge project. In the host source code debugging, according to the EasyBox configuration method, all the warehouses of live broadcast need to be introduced. The configuration is cumbersome and prone to compilation problems. Based on the EasyBox tool, live broadcast has developed its own source code debugging plug-in, which can support one-click configuration of live broadcast source code debugging to the host. In order to facilitate debugging problems, the plug-in capabilities have been expanded, and the mapping of live broadcast's own widget strength has been developed in the EasyBox binary source code mapping mechanism. The principle diagram is as follows:

3. Access protocol optimization

SDKs are iterating rapidly, and many protocols are exposed to the outside world. Each host has different conditions, and the cost of implementing each protocol is very high for business access. Live broadcast provides a series of small component binaries and general implementation protocols. Hosts can freely introduce them according to their own conditions to reduce access costs.

IV. Benefits

Based on the above steps of transformation, the benefits are quite obvious, mainly the improvement of efficiency:

• With the help of EasyBox and mgit, the engineering complexity is reduced and the development cost of live broadcast business students is reduced.
• Based on the differentiated construction solution design of live broadcast, vertical product function customization does not need to invade the core business of live broadcast, achieving flexible customization and free cutting of functional components
• With the help of the automatic access platform, the communication and docking costs are greatly reduced, and the access and use of SDK are automated and standardized.
• Develop EasyBox source code debugging plug-in to facilitate quick debugging by students

V. Conclusion

Live engineering is based on the EasyBox tool chain in the factory, combined with the specific demands of live broadcast, and evolved into its own engineering development model. Whether it is engineering transformation or access efficiency optimization, returning to the essence, the ultimate goal is to improve development efficiency and help products quickly iterate. ​