Import a pallet

This guide demonstrates how to quickly integrate both local and external pallets in a runtime. For more detailed step-by-step instructions, see Add a pallet to the runtime.

This guide illustrates:

  • How to include a custom local pallet that implements an event and a call for the runtime.
  • How to include an external pallet from Crates.io in the runtime.

Create a local pallet

  1. Create a local pallet called pallet_something.
  2. Import this pallet by adding the following to /runtime/src/lib.rs:

    // Import your pallet.
    pub use pallet_something;
  3. Configure your pallet's runtime implementation. Assume the local pallet only has the Event and Call types exposed to the runtime. Add the following to /runtime/src/lib.rs:

    // Configure your pallet.
    impl pallet_something::Config for Runtime {
    	type Event = Event;
    	type Call = Call;
    }
  4. Declare your pallet and the items it exposes. Include the additional Pallet and Storage types for the runtime macro. In construct_runtime!, add the following:

    construct_runtime!(
    	pub enum Runtime where
    	Block = Block,
    	NodeBlock = opaque::Block,
    	UncheckedExtrinsic = UncheckedExtrinsic
    	{
    		/* --snip-- */
    		Something: pallet_something::{Pallet, Call, Storage, Event<T>},
    		/* --snip-- */
    	}
    );
  5. Update /runtime/Cargo.toml

    In /runtime/Cargo.toml, include your pallet as a local dependency in std and add runtime-benchmarks. For example:

    # --snip--
    pallet-something = { default-features = false,   path = '../pallets/something'
    version = '3.0.0'
    # --snip--
    [features]
    default = ['std']
    runtime-benchmarks = [
     # --snip--
     'pallet-something/runtime-benchmarks',
    ]
    std = [
     'pallet-something/std',
     # --snip--
    ]

Import an external pallet

To add an external pallet, you use a similar method to the one you used with the local pallet, but you must include all of the types your pallet exposes. You must also include the relevant parameter types and constants. For examples of how to declare parameters and constants, see pallet_timestamp.

The following is an example of how you would add an external pallet to the /runtime/Cargo.toml dependencies if the pallet is hosted on crates.parity.io:

[dependencies]
pallet-external = {default-features = false, git = "https://github.com/paritytech/substrate.git", version = "4.0.0-dev"}

# --snip--
runtime-benchmarks = [
  /* --snip */
  'pallet-external/runtime-benchmarks',
]
std = [
  'pallet-external/std',
  # --snip--
]

Examples