Packages

Learn about basics of Substreams packages

There are a lot of developers building Substreams and creating very useful transformations that can be reused by other people. Once a Substreams is developed, you can pack it into a Substreams package and share it with other people!

Essentially, a Substreams package is a ready-to-consume binary file, which contains all the necessary dependencies (manifest, modules, protobufs...). The standard file extension for a Substreams package is .spkg.

The Substreams Registry

In order to facilitate how developers share Substreams packages, the Substreams Registry (https://substreams.dev) was created. In the Registry, developers can discover and push Substreams.

For example, the ERC20 Balance Changes package is stored at the registry (https://substreams.dev/streamingfast/erc20-balance-changes/v1.1.0).

Using a Package

You can easily run a Substreams package by inputting the .spkg file in the CLI:

substreams gui \
 https://spkg.io/streamingfast/erc20-balance-changes-v1.1.0.spkg \
 map_balance_changes \
 -e mainnet.eth.streamingfast.io:443 \
 --start-block 1397553

Creating a Package

You can create a Substreams package by executing the substreams pack command in the CLI. Given a Substreams project, you can create a new package from a manifest (substreams.yaml):

substreams pack ./substreams.yaml

Package Dependencies

Developers can use modules and protobuf definitions from other Substreams packages when imports is defined in the manifest.

Important: To avoid potential naming collisions select unique .proto filenames and namespaces specifying fully qualified paths.

Local Protobuf filenames take precedence over the imported package's proto files.