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Minor doc fixes (#10537)

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Justin Johnson 2021-11-14 14:48:53 -06:00 committed by GitHub
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4
docs/building-modules/module-manager.md
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@ -20,7 +20,7 @@ Application module interfaces exist to facilitate the composition of modules tog
The `AppModuleBasic` interface exists to define independent methods of the module, i.e. those that do not depend on other modules in the application. This allows for the construction of the basic application structure early in the application definition, generally in the `init()` function of the [main application file](../basics/app-anatomy.md#core-application-file).
The `AppModule` interface exists to define inter-dependent module methods. Many modules need to interract with other modules, typically through [`keeper`s](./keeper.md), which means there is a need for an interface where modules list their `keeper`s and other methods that require a reference to another module's object. `AppModule` interface also enables the module manager to set the order of execution between module's methods like `BeginBlock` and `EndBlock`, which is important in cases where the order of execution between modules matters in the context of the application.
The `AppModule` interface exists to define inter-dependent module methods. Many modules need to interact with other modules, typically through [`keeper`s](./keeper.md), which means there is a need for an interface where modules list their `keeper`s and other methods that require a reference to another module's object. `AppModule` interface also enables the module manager to set the order of execution between module's methods like `BeginBlock` and `EndBlock`, which is important in cases where the order of execution between modules matters in the context of the application.
Lastly the interface for genesis functionality `AppModuleGenesis` is separated out from full module functionality `AppModule` so that modules which
are only used for genesis can take advantage of the `Module` patterns without having to define many placeholder functions.
@ -56,7 +56,7 @@ Let us go through the two added methods:
- `InitGenesis(sdk.Context, codec.JSONCodec, json.RawMessage)`: Initializes the subset of the state managed by the module. It is called at genesis (i.e. when the chain is first started).
- `ExportGenesis(sdk.Context, codec.JSONCodec)`: Exports the latest subset of the state managed by the module to be used in a new genesis file. `ExportGenesis` is called for each module when a new chain is started from the state of an existing chain.
It does not have its own manager, and exists separately from [`AppModule`](#appmodule) only for modules that exist only to implement genesis functionalities, so that they can be managed without having to implement all of `AppModule`'s methods. If the module is not only used during genesis, `InitGenesis(sdk.Context, codec.JSONCodec, json.RawMessage)` and `ExportGenesis(sdk.Context, codec.JSONCodec)` will generally be defined as methods of the concrete type implementing the `AppModule` interface.
It does not have its own manager, and exists separately from [`AppModule`](#appmodule) only for modules that exist only to implement genesis functionalities, so that they can be managed without having to implement all of `AppModule`'s methods. If the module is not only used during genesis, `InitGenesis(sdk.Context, codec.JSONCodec, json.RawMessage)` and `ExportGenesis(sdk.Context, codec.JSONCodec)` will generally be defined as methods of the concrete type implementing the `AppModule` interface.
### `AppModule`

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docs/intro/why-app-specific.md
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@ -8,7 +8,7 @@ This document explains what application-specific blockchains are, and why develo
## What are application-specific blockchains?
Application-specific blockchains are blockchains customized to operate a single application. Instead of building a decentralised application on top of an underlying blockchain like Ethereum, developers build their own blockchain from the ground up. This means building a full-node client, a light-client, and all the necessary interfaces (CLI, REST, ...) to interract with the nodes.
Application-specific blockchains are blockchains customized to operate a single application. Instead of building a decentralised application on top of an underlying blockchain like Ethereum, developers build their own blockchain from the ground up. This means building a full-node client, a light-client, and all the necessary interfaces (CLI, REST, ...) to interact with the nodes.
```
^ +-------------------------------+ ^
@ -33,7 +33,7 @@ Virtual-machine blockchains like Ethereum addressed the demand for more programm
Virtual-machine blockchains came in with a new value proposition. Their state-machine incorporates a virtual-machine that is able to interpret turing-complete programs called Smart Contracts. These Smart Contracts are very good for use cases like one-time events (e.g. ICOs), but they can fall short for building complex decentralised platforms. Here is why:
- Smart Contracts are generally developed with specific programming languages that can be interpreted by the underlying virtual-machine. These programming languages are often immature and inherently limited by the constraints of the virtual-machine itself. For example, the Ethereum Virtual Machine does not allow developers to implement automatic execution of code. Developers are also limited to the account-based system of the EVM, and they can only choose from a limited set of functions for their cryptographic operations. These are examples, but they hint at the lack of **flexibility** that a smart contract environment often entails.
- Smart Contracts are all run by the same virtual machine. This means that they compete for resources, which can severly restrain **performance**. And even if the state-machine were to be split in multiple subsets (e.g. via sharding), Smart Contracts would still need to be interpeted by a virtual machine, which would limit performance compared to a native application implemented at state-machine level (our benchmarks show an improvement on the order of x10 in performance when the virtual-machine is removed).
- Smart Contracts are all run by the same virtual machine. This means that they compete for resources, which can severely restrain **performance**. And even if the state-machine were to be split in multiple subsets (e.g. via sharding), Smart Contracts would still need to be interpeted by a virtual machine, which would limit performance compared to a native application implemented at state-machine level (our benchmarks show an improvement on the order of 10x in performance when the virtual-machine is removed).
- Another issue with the fact that Smart Contracts share the same underlying environment is the resulting limitation in **sovereignty**. A decentralised application is an ecosystem that involves multiple players. If the application is built on a general-purpose virtual-machine blockchain, stakeholders have very limited sovereignty over their application, and are ultimately superseded by the governance of the underlying blockchain. If there is a bug in the application, very little can be done about it.
Application-Specific Blockchains are designed to address these shortcomings.
@ -46,7 +46,7 @@ Application-specific blockchains give maximum flexibility to developers:
- In Cosmos blockchains, the state-machine is typically connected to the underlying consensus engine via an interface called the [ABCI](https://docs.tendermint.com/v0.34/spec/abci/). This interface can be wrapped in any programming language, meaning developers can build their state-machine in the programming language of their choice.
- Developers can choose among multiple frameworks to build their state-machine. The most widely used today is the Cosmos SDK, but others exist (e.g. [Lotion](https://github.com/nomic-io/lotion), [Weave](https://github.com/iov-one/weave), ...). The choice will most of the time be done based on the programming language they want to use (Cosmos SDK and Weave are in Golang, Lotion is in Javascript, ...).
- Developers can choose among multiple frameworks to build their state-machine. The most widely used today is the Cosmos SDK, but others exist (e.g. [Lotion](https://github.com/nomic-io/lotion), [Weave](https://github.com/iov-one/weave), ...). Typically the choice will be made based on the programming language they want to use (Cosmos SDK and Weave are in Golang, Lotion is in Javascript, ...).
- The ABCI also allows developers to swap the consensus engine of their application-specific blockchain. Today, only Tendermint is production-ready, but in the future other consensus engines are expected to emerge.
- Even when they settle for a framework and consensus engine, developers still have the freedom to tweak them if they don't perfectly match their requirements in their pristine forms.
- Developers are free to explore the full spectrum of tradeoffs (e.g. number of validators vs transaction throughput, safety vs availability in asynchrony, ...) and design choices (DB or IAVL tree for storage, UTXO or account model, ...).
@ -56,7 +56,7 @@ The list above contains a few examples that show how much flexibility applicatio
### Performance
Decentralised applications built with Smart Contracts are inherently capped in performance by the underlying environment. For a decentralised application to optimise performance, it needs to be built as an application-specific blockchains. Next are some of the benefits an application-specific blockchain brings in terms of performance:
Decentralised applications built with Smart Contracts are inherently capped in performance by the underlying environment. For a decentralised application to optimise performance, it needs to be built as an application-specific blockchain. Next are some of the benefits an application-specific blockchain brings in terms of performance:
- Developers of application-specific blockchains can choose to operate with a novel consensus engine such as Tendermint BFT. Compared to Proof-of-Work (used by most virtual-machine blockchains today), it offers significant gains in throughput.
- An application-specific blockchain only operates a single application, so that the application does not compete with others for computation and storage. This is the opposite of most non-sharded virtual-machine blockchains today, where smart contracts all compete for computation and storage.
@ -72,9 +72,9 @@ Security is hard to quantify, and greatly varies from platform to platform. That
### Sovereignty
One of the major benefits of application-specific blockchains is sovereignty. A decentralised application is an ecosystem that involves many actors: users, developers, third-party services, and more. When developers build on virtual-machine blockchain where many decentralised applications coexist, the community of the application is different than the community of the underlying blockchain, and the latter supersedes the former in the governance process. If there is a bug or if a new feature is needed, stakeholders of the application have very little leeway to upgrade the code. If the community of the underlying blockchain refuses to act, nothing can happen.
One of the major benefits of application-specific blockchains is sovereignty. A decentralised application is an ecosystem that involves many actors: users, developers, third-party services, and more. When developers build on virtual-machine blockchain where many decentralised applications coexist, the community of the application is different than the community of the underlying blockchain, and the latter supersedes the former in the governance process. If there is a bug or if a new feature is needed, stakeholders of the application have very little leeway to upgrade the code. If the community of the underlying blockchain refuses to act, nothing can happen.
The fundamental issue here is that the governance of the application and the governance of the network are not aligned. This issue is solved by application-specific blockchains. Because application-specific blockchains specialize to operate a single application, stakeholders the application has full control over the entire chain. This ensures the community will not be stuck if a bug is discovered, and that it has the entire freedom to choose how it is going to evolve.
The fundamental issue here is that the governance of the application and the governance of the network are not aligned. This issue is solved by application-specific blockchains. Because application-specific blockchains specialize to operate a single application, stakeholders of the application have full control over the entire chain. This ensures that the community will not be stuck if a bug is discovered, and that it has the freedom to choose how it is going to evolve.
## Next {hide}