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Substreams Sink

Package Exports

  • substreams-sink

Readme

Substreams Sink CLI Node.js

Build Status npm version License

substreams-sink is the code template to build Substreams sinks in NodeJS. Sinks allows developers to pipe data extracted from a blockchain to a specified application.

📖 Documentation

Further resources

🚀 Quick start

Installation

npm install substreams-sink

Features

  • includes Commander.js helper CLI
  • includes tslog helper logger
  • includes Substreams run() helper method & RunOptions interface
  • handle reading/saving Substreams cursor.lock file
  • reads SUBSTREAMS_API_TOKEN from .env file
  • includes --verbose flag
  • includes --production-mode flag

CLI

Usage: substreams-sink run [options]

Substreams sink CLI module

Options:
  -e --substreams-endpoint <string>       Substreams gRPC endpoint to stream data from
  --manifest <string>                     URL of Substreams package
  --module-name <string>                  Name of the output module (declared in the manifest)
  -p, --params <string...>                Set a params for parameterizable modules. Can be specified multiple times. (ex: -p module1=valA -p module2=valX&valY) (default: [])
  -s --start-block <int>                  Start block to stream from (defaults to -1, which means the initialBlock of the first module you are streaming)
  -t --stop-block <int>                   Stop block to end stream at, inclusively
  --substreams-api-token <string>         API token for the substream endpoint
  --substreams-api-token-envvar <string>  Environnement variable name of the API token for the substream endpoint (default: "SUBSTREAMS_API_TOKEN")
  --delay-before-start <int>              [OPERATOR] Amount of time in milliseconds (ms) to wait before starting any internal processes, can be used to perform to maintenance on the pod before actually
                                          letting it starts
  --cursor-file <string>                  cursor lock file (default: "cursor.lock")
  --production-mode                       Enable Production Mode, with high-speed parallel processing (default: false)
  --verbose                               Enable verbose logging (default: false)
  --metrics-listen-address <string>       The process will listen on this address for Prometheus metrics requests (default: "localhost")
  --metrics-listen-port <int>             The process will listen on this port for Prometheus metrics requests (default: "9102")
  --metrics-disabled                      If set, will not send metrics to Prometheus (default: false)
  -h, --help                              display help for command

Example

import { fetchSubstream } from "@substreams/core";
import { run, logger, cli } from "substreams-sink";

import pkg from "./package.json" assert { type: "json" };

const program = cli.program(pkg);
const command = cli.option(program, pkg);

logger.setName(pkg.name);
export { logger };

// Custom user options interface
interface ActionOptions extends cli.RunOptions {
    customOption: any
    // ...
}

export async function action(options: ActionOptions) {
    const spkg = await fetchSubstream(options.manifest!);

    // Get command options
    const { customOption } = options;

    // Run substreams
    const substreams = run(spkg, options);

    substreams.on("anyMessage", async (messages: any) => {
      // Sink logic here
    });

    substreams.start(options.delayBeforeStart);
}