Subgraph Manifest

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The subgraph manifest, subgraph.yaml, defines the smart contracts & network your subgraph will index, the events from these contracts to pay attention to, and how to map event data to entities that Graph Node stores and allows to query.

The subgraph definition consists of the following files:

• subgraph.yaml: Contains the subgraph manifest

• schema.graphql: A GraphQL schema defining the data stored for your subgraph and how to query it via GraphQL

• mapping.ts: AssemblyScript Mappings code that translates event data into entities defined in your schema (e.g. mapping.ts in this guide)

A single subgraph can:

• Index data from multiple smart contracts (but not multiple networks).

• Index data from IPFS files using File Data Sources.

• Add an entry for each contract that requires indexing to the dataSources array.

The full specification for subgraph manifests can be found here.

For the example subgraph listed above, subgraph.yaml is:

specVersion: 0.0.4
description: Gravatar for Ethereum
repository: https://github.com/graphprotocol/graph-tooling
schema:
  file: ./schema.graphql
indexerHints:
  prune: auto
dataSources:
  - kind: ethereum/contract
    name: Gravity
    network: mainnet
    source:
      address: '0x2E645469f354BB4F5c8a05B3b30A929361cf77eC'
      abi: Gravity
      startBlock: 6175244
      endBlock: 7175245
    context:
      foo:
        type: Bool
        data: true
      bar:
        type: String
        data: 'bar'
    mapping:
      kind: ethereum/events
      apiVersion: 0.0.6
      language: wasm/assemblyscript
      entities:
        - Gravatar
      abis:
        - name: Gravity
          file: ./abis/Gravity.json
      eventHandlers:
        - event: NewGravatar(uint256,address,string,string)
          handler: handleNewGravatar
        - event: UpdatedGravatar(uint256,address,string,string)
          handler: handleUpdatedGravatar
      callHandlers:
        - function: createGravatar(string,string)
          handler: handleCreateGravatar
      blockHandlers:
        - handler: handleBlock
        - handler: handleBlockWithCall
          filter:
            kind: call
      file: ./src/mapping.ts

清单中要更新的重要条目是：

• specVersion: a semver version that identifies the supported manifest structure and functionality for the subgraph. The latest version is 1.2.0. See specVersion releases section to see more details on features & releases.

• description: a human-readable description of what the subgraph is. This description is displayed in Graph Explorer when the subgraph is deployed to Subgraph Studio.

• repository: the URL of the repository where the subgraph manifest can be found. This is also displayed in Graph Explorer.

• features: a list of all used feature names.

• indexerHints.prune: Defines the retention of historical block data for a subgraph. See prune in indexerHints section.

• dataSources.source: the address of the smart contract the subgraph sources, and the ABI of the smart contract to use. The address is optional; omitting it allows to index matching events from all contracts.

• dataSources.source.startBlock: the optional number of the block that the data source starts indexing from. In most cases, we suggest using the block in which the contract was created.

• dataSources.source.endBlock: The optional number of the block that the data source stops indexing at, including that block. Minimum spec version required: 0.0.9.

• dataSources.context: key-value pairs that can be used within subgraph mappings. Supports various data types like Bool, String, Int, Int8, BigDecimal, Bytes, List, and BigInt. Each variable needs to specify its type and data. These context variables are then accessible in the mapping files, offering more configurable options for subgraph development.

• dataSources.mapping.entities: the entities that the data source writes to the store. The schema for each entity is defined in the schema.graphql file.

• dataSources.mapping.abis: one or more named ABI files for the source contract as well as any other smart contracts that you interact with from within the mappings.

• dataSources.mapping.eventHandlers: lists the smart contract events this subgraph reacts to and the handlers in the mapping—./src/mapping.ts in the example—that transform these events into entities in the store.

• dataSources.mapping.callHandlers: lists the smart contract functions this subgraph reacts to and handlers in the mapping that transform the inputs and outputs to function calls into entities in the store.

• dataSources.mapping.blockHandlers: lists the blocks this subgraph reacts to and handlers in the mapping to run when a block is appended to the chain. Without a filter, the block handler will be run every block. An optional call-filter can be provided by adding a filter field with kind: call to the handler. This will only run the handler if the block contains at least one call to the data source contract.

A single subgraph can index data from multiple smart contracts. Add an entry for each contract from which data needs to be indexed to the dataSources array.

Event handlers in a subgraph react to specific events emitted by smart contracts on the blockchain and trigger handlers defined in the subgraph's manifest. This enables subgraphs to process and store event data according to defined logic.

An event handler is declared within a data source in the subgraph's YAML configuration. It specifies which events to listen for and the corresponding function to execute when those events are detected.

dataSources:
  - kind: ethereum/contract
    name: Gravity
    network: dev
    source:
      address: '0x731a10897d267e19b34503ad902d0a29173ba4b1'
      abi: Gravity
    mapping:
      kind: ethereum/events
      apiVersion: 0.0.6
      language: wasm/assemblyscript
      entities:
        - Gravatar
        - Transaction
      abis:
        - name: Gravity
          file: ./abis/Gravity.json
      eventHandlers:
        - event: Approval(address,address,uint256)
          handler: handleApproval
        - event: Transfer(address,address,uint256)
          handler: handleTransfer
          topic1: ['0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045', '0xc8dA6BF26964aF9D7eEd9e03E53415D37aA96325'] # Optional topic filter which filters only events with the specified topic.

While events provide an effective way to collect relevant changes to the state of a contract, many contracts avoid generating logs to optimize gas costs. In these cases, a subgraph can subscribe to calls made to the data source contract. This is achieved by defining call handlers referencing the function signature and the mapping handler that will process calls to this function. To process these calls, the mapping handler will receive an ethereum.Call as an argument with the typed inputs to and outputs from the call. Calls made at any depth in a transaction's call chain will trigger the mapping, allowing activity with the data source contract through proxy contracts to be captured.

调用处理程序只会在以下两种情况之一触发：当指定的函数被合约本身以外的账户调用时，或者当它在 Solidity 中被标记为外部，并作为同一合约中另一个函数的一部分被调用时。

To define a call handler in your manifest, simply add a callHandlers array under the data source you would like to subscribe to.

dataSources:
  - kind: ethereum/contract
    name: Gravity
    network: mainnet
    source:
      address: '0x731a10897d267e19b34503ad902d0a29173ba4b1'
      abi: Gravity
    mapping:
      kind: ethereum/events
      apiVersion: 0.0.6
      language: wasm/assemblyscript
      entities:
        - Gravatar
        - Transaction
      abis:
        - name: Gravity
          file: ./abis/Gravity.json
      callHandlers:
        - function: createGravatar(string,string)
          handler: handleCreateGravatar

The function is the normalized function signature to filter calls by. The handler property is the name of the function in your mapping you would like to execute when the target function is called in the data source contract.

Each call handler takes a single parameter that has a type corresponding to the name of the called function. In the example subgraph above, the mapping contains a handler for when the createGravatar function is called and receives a CreateGravatarCall parameter as an argument:

import { CreateGravatarCall } from '../generated/Gravity/Gravity'
import { Transaction } from '../generated/schema'

export function handleCreateGravatar(call: CreateGravatarCall): void {
  let id = call.transaction.hash
  let transaction = new Transaction(id)
  transaction.displayName = call.inputs._displayName
  transaction.imageUrl = call.inputs._imageUrl
  transaction.save()
}

The handleCreateGravatar function takes a new CreateGravatarCall which is a subclass of ethereum.Call, provided by @graphprotocol/graph-ts, that includes the typed inputs and outputs of the call. The CreateGravatarCall type is generated for you when you run graph codegen.

除了订阅合约事件或函数调用之外，子图可能还希望在将新区块附加到链上时更新其数据。 为了实现这一点，子图可以在每个区块之后，或匹配预定义过滤器的区块之后，运行一个函数。

filter:
  kind: call

The defined handler will be called once for every block which contains a call to the contract (data source) the handler is defined under.

块处理程序没有过滤器将确保每个块都调用处理程序。对于每种过滤器类型，一个数据源只能包含一个块处理程序。

dataSources:
  - kind: ethereum/contract
    name: Gravity
    network: dev
    source:
      address: '0x731a10897d267e19b34503ad902d0a29173ba4b1'
      abi: Gravity
    mapping:
      kind: ethereum/events
      apiVersion: 0.0.6
      language: wasm/assemblyscript
      entities:
        - Gravatar
        - Transaction
      abis:
        - name: Gravity
          file: ./abis/Gravity.json
      blockHandlers:
        - handler: handleBlock
        - handler: handleBlockWithCallToContract
          filter:
            kind: call

blockHandlers:
  - handler: handleBlock
    filter:
      kind: polling
      every: 10

The defined handler will be called once for every n blocks, where n is the value provided in the every field. This configuration allows the subgraph to perform specific operations at regular block intervals.

blockHandlers:
  - handler: handleOnce
    filter:
      kind: once

带有 "once filter" 的所定义处理程序将在所有其他处理程序运行之前仅被调用一次。这种配置允许子图将该处理程序用作初始化处理程序，在索引开始时执行特定任务。

export function handleOnce(block: ethereum.Block): void {
  let data = new InitialData(Bytes.fromUTF8('initial'))
  data.data = 'Setup data here'
  data.save()
}

The mapping function will receive an ethereum.Block as its only argument. Like mapping functions for events, this function can access existing subgraph entities in the store, call smart contracts and create or update entities.

import { ethereum } from '@graphprotocol/graph-ts'

export function handleBlock(block: ethereum.Block): void {
  let id = block.hash
  let entity = new Block(id)
  entity.save()
}

如果您需要在 Solidity 中处理匿名事件，可以通过提供事件的主题 0 来实现，如示例所示：

eventHandlers:
  - event: LogNote(bytes4,address,bytes32,bytes32,uint256,bytes)
    topic0: '0x644843f351d3fba4abcd60109eaff9f54bac8fb8ccf0bab941009c21df21cf31'
    handler: handleGive

An event will only be triggered when both the signature and topic 0 match. By default, topic0 is equal to the hash of the event signature.

Starting from specVersion 0.0.5 and apiVersion 0.0.7, event handlers can have access to the receipt for the transaction which emitted them.

To do so, event handlers must be declared in the subgraph manifest with the new receipt: true key, which is optional and defaults to false.

eventHandlers:
  - event: NewGravatar(uint256,address,string,string)
    handler: handleNewGravatar
    receipt: true

Inside the handler function, the receipt can be accessed in the Event.receipt field. When the receipt key is set to false or omitted in the manifest, a null value will be returned instead.

区块内数据源的触发器使用以下流程进行排序：

1. 事件和调用触发器首先按区块内的交易索引排序。
2. 同一交易中的事件和调用触发器使用约定进行排序：首先是事件触发器，然后是调用触发器，每种类型都遵循它们在清单中定义的顺序。
3. 区块触发器按照它们在清单中定义的顺序，在事件和调用触发器之后运行。

这些排序规则可能会发生变化。

EVM兼容智能合约中的一种常见模式是使用注册表或工厂合约，其中一个合约创建、管理或引用任意数量的其他合约，每个合约都有自己的状态和事件。

The addresses of these sub-contracts may or may not be known upfront and many of these contracts may be created and/or added over time. This is why, in such cases, defining a single data source or a fixed number of data sources is impossible and a more dynamic approach is needed: data source templates.

First, you define a regular data source for the main contract. The snippet below shows a simplified example data source for the Uniswap exchange factory contract. Note the NewExchange(address,address) event handler. This is emitted when a new exchange contract is created on-chain by the factory contract.

dataSources:
  - kind: ethereum/contract
    name: Factory
    network: mainnet
    source:
      address: '0xc0a47dFe034B400B47bDaD5FecDa2621de6c4d95'
      abi: Factory
    mapping:
      kind: ethereum/events
      apiVersion: 0.0.6
      language: wasm/assemblyscript
      file: ./src/mappings/factory.ts
      entities:
        - Directory
      abis:
        - name: Factory
          file: ./abis/factory.json
      eventHandlers:
        - event: NewExchange(address,address)
          handler: handleNewExchange

Then, you add data source templates to the manifest. These are identical to regular data sources, except that they lack a pre-defined contract address under source. Typically, you would define one template for each type of sub-contract managed or referenced by the parent contract.

dataSources:
  - kind: ethereum/contract
    name: Factory
    # ... other source fields for the main contract ...
templates:
  - name: Exchange
    kind: ethereum/contract
    network: mainnet
    source:
      abi: Exchange
    mapping:
      kind: ethereum/events
      apiVersion: 0.0.6
      language: wasm/assemblyscript
      file: ./src/mappings/exchange.ts
      entities:
        - Exchange
      abis:
        - name: Exchange
          file: ./abis/exchange.json
      eventHandlers:
        - event: TokenPurchase(address,uint256,uint256)
          handler: handleTokenPurchase
        - event: EthPurchase(address,uint256,uint256)
          handler: handleEthPurchase
        - event: AddLiquidity(address,uint256,uint256)
          handler: handleAddLiquidity
        - event: RemoveLiquidity(address,uint256,uint256)
          handler: handleRemoveLiquidity

In the final step, you update your main contract mapping to create a dynamic data source instance from one of the templates. In this example, you would change the main contract mapping to import the Exchange template and call the Exchange.create(address) method on it to start indexing the new exchange contract.

import { Exchange } from '../generated/templates'

export function handleNewExchange(event: NewExchange): void {
  // Start indexing the exchange; `event.params.exchange` is the
  // address of the new exchange contract
  Exchange.create(event.params.exchange)
}

Data source contexts allow passing extra configuration when instantiating a template. In our example, let's say exchanges are associated with a particular trading pair, which is included in the NewExchange event. That information can be passed into the instantiated data source, like so:

import { Exchange } from '../generated/templates'

export function handleNewExchange(event: NewExchange): void {
  let context = new DataSourceContext()
  context.setString('tradingPair', event.params.tradingPair)
  Exchange.createWithContext(event.params.exchange, context)
}

Inside a mapping of the Exchange template, the context can then be accessed:

import { dataSource } from '@graphprotocol/graph-ts'

let context = dataSource.context()
let tradingPair = context.getString('tradingPair')

There are setters and getters like setString and getString for all value types.

The startBlock is an optional setting that allows you to define from which block in the chain the data source will start indexing. Setting the start block allows the data source to skip potentially millions of blocks that are irrelevant. Typically, a subgraph developer will set startBlock to the block in which the smart contract of the data source was created.

dataSources:
  - kind: ethereum/contract
    name: ExampleSource
    network: mainnet
    source:
      address: '0xc0a47dFe034B400B47bDaD5FecDa2621de6c4d95'
      abi: ExampleContract
      startBlock: 6627917
    mapping:
      kind: ethereum/events
      apiVersion: 0.0.6
      language: wasm/assemblyscript
      file: ./src/mappings/factory.ts
      entities:
        - User
      abis:
        - name: ExampleContract
          file: ./abis/ExampleContract.json
      eventHandlers:
        - event: NewEvent(address,address)
          handler: handleNewEvent

The indexerHints setting in a subgraph's manifest provides directives for indexers on processing and managing a subgraph. It influences operational decisions across data handling, indexing strategies, and optimizations. Presently, it features the prune option for managing historical data retention or pruning.

indexerHints.prune: Defines the retention of historical block data for a subgraph. Options include:

1. "never": No pruning of historical data; retains the entire history.
2. "auto": Retains the minimum necessary history as set by the indexer, optimizing query performance.
3. A specific number: Sets a custom limit on the number of historical blocks to retain.

indexerHints:
  prune: auto

History as of a given block is required for:

• Time travel queries, which enable querying the past states of these entities at specific blocks throughout the subgraph's history
• Using the subgraph as a graft base in another subgraph, at that block
• Rewinding the subgraph back to that block

If historical data as of the block has been pruned, the above capabilities will not be available.

For subgraphs leveraging time travel queries, it's advisable to either set a specific number of blocks for historical data retention or use prune: never to keep all historical entity states. Below are examples of how to configure both options in your subgraph's settings:

To retain a specific amount of historical data:

indexerHints:
  prune: 1000 # Replace 1000 with the desired number of blocks to retain

To preserve the complete history of entity states:

indexerHints:
  prune: never