refactor: use the Failover Provider #28
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,102 @@ | ||
| import type { | ||
| JsonRpcApiProviderOptions, | ||
| JsonRpcPayload, | ||
| JsonRpcResult, | ||
| Networkish, | ||
| } from 'ethers'; | ||
| import { JsonRpcProvider, FetchRequest } from 'ethers'; | ||
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| /** | ||
| * A `JsonRpcProvider` that transparently fails over to a list of backup JSON-RPC endpoints. | ||
| */ | ||
| export default class FailoverJsonRpcProvider extends JsonRpcProvider { | ||
| private readonly _rpcEndpoints: (string | FetchRequest)[]; | ||
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| /** | ||
| * @param rpcEndpoints An array of JSON-RPC endpoints. The order determines the failover order. | ||
| */ | ||
| constructor( | ||
| rpcEndpoints: (string | FetchRequest)[], | ||
| network?: Networkish, | ||
| options?: JsonRpcApiProviderOptions, | ||
| ) { | ||
| super(rpcEndpoints[0], network, options); | ||
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| this._rpcEndpoints = rpcEndpoints; | ||
| } | ||
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| /** | ||
| * Overrides the `_send` method to try each endpoint until the request succeeds. | ||
| * | ||
| * @param payload - The JSON-RPC payload or array of payloads to send. | ||
| * @returns A promise that resolves to the result of the first successful JSON-RPC call. | ||
| */ | ||
| public override async _send( | ||
| payload: JsonRpcPayload | Array<JsonRpcPayload>, | ||
| ): Promise<Array<JsonRpcResult>> { | ||
| // The actual sending of the request is the same as in the base class. | ||
| // The only difference is that we're creating a new `FetchRequest` for each endpoint, | ||
| // instead of getting the `request` from `_getConnection()`, which will return the *primary* (first) endpoint. | ||
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| const errors: { rpcEndpoint: string; error: any }[] = []; | ||
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| // Try each endpoint, in order. | ||
| for (const rpcEndpoint of this._rpcEndpoints) { | ||
| try { | ||
| let request: FetchRequest; | ||
|
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| if (typeof rpcEndpoint === 'string') { | ||
| request = new FetchRequest(rpcEndpoint); | ||
| } else { | ||
| request = rpcEndpoint.clone(); | ||
| } | ||
|
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| request.body = JSON.stringify(payload); | ||
| request.setHeader('content-type', 'application/json'); | ||
| const response = await request.send(); | ||
| response.assertOk(); | ||
|
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| let resp = response.bodyJson; | ||
| if (!Array.isArray(resp)) { | ||
| resp = [resp]; | ||
| } | ||
|
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| return resp; | ||
| } catch (error: any) { | ||
| const endpointUrl = this._getRpcEndpointUrl(rpcEndpoint); | ||
| errors.push({ rpcEndpoint: endpointUrl, error }); | ||
| } | ||
| } | ||
|
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| // All endpoints failed. Throw an error containing the details. | ||
| const errorMessages = errors | ||
| .map( | ||
| (e) => | ||
| `Endpoint '${e.rpcEndpoint}' failed with error: ${e.error.message}.`, | ||
| ) | ||
| .join('\n'); | ||
|
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| const aggregatedError = new Error( | ||
| `All RPC endpoints failed:\n${errorMessages}`, | ||
| ) as Error & { errors: { rpcEndpoint: string; error: any }[] }; | ||
|
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| aggregatedError.errors = errors; | ||
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| throw aggregatedError; | ||
| } | ||
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| /** | ||
| * Returns a copy of the endpoint URLs used by the provider. | ||
| */ | ||
| public getRpcEndpointUrls(): string[] { | ||
| return this._rpcEndpoints.map(this._getRpcEndpointUrl); | ||
| } | ||
|
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| private _getRpcEndpointUrl(rpcEndpoint: string | FetchRequest): string { | ||
| if (typeof rpcEndpoint === 'string') { | ||
| return rpcEndpoint; | ||
| } | ||
|
|
||
| return rpcEndpoint.url; | ||
| } | ||
| } |
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so many env vars! what do you think about taking a single RPC_CONFIG env var that takes a JSON string with a strict schema that we validate with e.g.
zodinappSettings?either way, for now I think this is still OK — gonna get a bit crazy when we add more networks soon though.
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Yes, I agree. Take a look at this commit (67c931d). Was this what you had in mind?