ksmnetwork / subwasm

Subwasm is a cli utility to help you know more about WASM Runtimes. It help downloading, inspecting and comparing Substrate based chains such as Polkadot or Kusama.

subwasm

Unfortunately, the crate of the project and its dependencies are squatted on crates.io. The squatter remains unresponsive and the crates.io team does not care. I strongly recommend NOT to install the old version from crates.io. Check the Install chapter below to see how to install from this repo or use the official binary packages.

Introduction

The metadata of a given runtime is a critical piece of information as it describes how one can interact with the runtime, what operations are possible and what are the signatures of the calls. It contains the exhaustive list of all the features publicly exposed by the runtime.

This tool only works with Substrate-based runtimes which are >=V11. For earlier versions, you’ll need to connect to an archive node.

Any node can be queried to provide its current metadata. This can be displayed in json format for instance. This is a great way to have a peek at what the runtime can do.

Sample runs

Capabilities

subwasm allows:

• getting the latest metadata from a running node

• getting the latest runtime (wasm) from a running node

• getting runtime and metadata at any point of time using a Block hash as reference

• getting the metadata from a a wasm file without any node

• extracting information (those not requiring storage) from a runtime as wasm file

• (de)compress a given runtime WASM

Install

Using Cargo

cargo install --locked --git https://github.com/chevdor/subwasm --tag v0.16.1

Homebrew

MacOS Homebrew users can use:

brew tap chevdor/subwasm https://github.com/chevdor/subwasm
brew install subwasm

Linux

wget https://github.com/chevdor/subwasm/releases/download/v0.16.1/subwasm_linux_amd64_v0.16.1 -O subwasm.deb
sudo dpkg -i subwasm.deb
subwasm --help

Usage

Command: --help

subwasm 0.17.0
chevdor <[e-mail]>:Wilfried Kopp <[e-mail]
`subwasm` allows fetching, parsing and calling some methods on WASM runtimes of Substrate based
chains

USAGE:
    subwasm [OPTIONS] <SUBCOMMAND>

OPTIONS:
    -h, --help       Print help information
    -j, --json       Output as json
    -q, --quiet      Less output
    -V, --version    Print version information

SUBCOMMANDS:
    compress      Compress a given runtime wasm file. You will get an error if you try
                      compressing a runtime that is already compressed
    decompress    Decompress a given runtime wasm file. You may pass a runtime that is
                      uncompressed already. In that case, you will get the same content as output.
                      This is useful if you want to decompress "no matter what" and don't really
                      know whether the input will be compressed or not
    diff          Compare 2 runtimes
    get           Get/Download the runtime wasm from a running node through rpc
    help          Print this message or the help of the given subcommand(s)
    info          The `info` command returns summarized information about a runtime
    metadata      Returns the metadata as a json object. You may also use the "meta" alias

Command: get

subwasm-get 0.17.0
chevdor <[e-mail]>:Wilfried Kopp <[e-mail]
Get/Download the runtime wasm from a running node through rpc

USAGE:
    subwasm get [OPTIONS] [URL]

ARGS:
    <URL>    The node url including (mandatory) the port number. Example: ws://localhost:9944 or
             http://localhost:9933 [default: http://localhost:9933]

OPTIONS:
    -b, --block <BLOCK>      The optional block where to fetch the runtime. That allows fetching
                             older runtimes but you will need to connect to archive nodes.
                             Currently, you must pass a block hash. Passing the block numbers is not
                             supported
        --chain <CHAIN>      Provide the name of a chain and a random url amongst a list of known
                             nodes will be used. If you pass a valid --chain, --url will be ignored
                             --chain local = http://localhost:9933
    -h, --help               Print help information
    -j, --json               Output as json
    -o, --output <OUTPUT>    You may specifiy the output filename where the runtime will be saved.
                             If not provided, we will figure out an appropriate default name based
                             on a counter: runtime_NNN.wasm where NNN is incrementing to make sure
                             you do not override previous runtime. If you specify an existing file
                             as output, it will be overwritten
    -V, --version            Print version information

Command: info

subwasm-info 0.17.0
chevdor <[e-mail]>:Wilfried Kopp <[e-mail]
The `info` command returns summarized information about a runtime

USAGE:
    subwasm info [OPTIONS] [SOURCE]

ARGS:
    <SOURCE>    The wasm file to load. It can be a path on your local filesystem such as
                /tmp/runtime.wasm or a node url such as http://localhost:9933 or
                ws://localhost:9944 [default: runtime_000.wasm]

OPTIONS:
    -b, --block <BLOCK>    The optional block where to fetch the runtime. That allows fetching older
                           runtimes but you will need to connect to archive nodes. Currently, you
                           must pass a block hash. Passing the block numbers is not supported
        --chain <CHAIN>    Provide the name of a chain and a random url amongst a list of known
                           nodes will be used. If you pass a valid --chain, --url will be ignored
                           --chain local = http://localhost:9933
    -h, --help             Print help information
    -j, --json             Output as json
    -V, --version          Print version information

Command: meta

subwasm-metadata 0.17.0
chevdor <[e-mail]>:Wilfried Kopp <[e-mail]
Returns the metadata as a json object. You may also use the "meta" alias

USAGE:
    subwasm metadata [OPTIONS] [SOURCE]

ARGS:
    <SOURCE>    The wasm file to load. It can be a path on your local filesystem such as
                /tmp/runtime.wasm or a node url such as http://localhost:9933 or
                ws://localhost:9944 [default: runtime_000.wasm]

OPTIONS:
    -b, --block <BLOCK>      The optional block where to fetch the runtime. That allows fetching
                             older runtimes but you will need to connect to archive nodes.
                             Currently, you must pass a block hash. Passing the block numbers is not
                             supported
        --chain <CHAIN>      Provide the name of a chain and a random url amongst a list of known
                             nodes will be used. If you pass a valid --chain, --url will be ignored
                             --chain local = http://localhost:9933
    -h, --help               Print help information
    -j, --json               Output as json
    -m, --module <MODULE>    Without this flag, the metadata command display the list of all
                             modules. Using this flag, you will only see the module of your choice
                             and a few details about it
    -V, --version            Print version information

Command: diff

subwasm-diff 0.17.0
chevdor <[e-mail]>:Wilfried Kopp <[e-mail]
Compare 2 runtimes

USAGE:
    subwasm diff [OPTIONS] [ARGS]

ARGS:
    <SRC_A>    The first source [default: runtime_000.wasm]
    <SRC_B>    The second source [default: runtime_001.wasm]

OPTIONS:
    -a, --chain-a <CHAIN_A>    Provide the name of a chain and a random url amongst a list of known
                               nodes will be used. If you pass a valid --chain, --url will be
                               ignored --chain local = http://localhost:9933
    -b, --chain-b <CHAIN_B>    Provide the name of a chain and a random url amongst a list of known
                               nodes will be used. If you pass a valid --chain, --url will be
                               ignored --chain local = http://localhost:9933
    -h, --help                 Print help information
    -j, --json                 Output as json
    -V, --version              Print version information

Command: compress

subwasm-compress 0.17.0
chevdor <[e-mail]>:Wilfried Kopp <[e-mail]
Compress a given runtime wasm file. You will get an error if you try compressing a runtime that is
already compressed

USAGE:
    subwasm compress [OPTIONS] <INPUT> <OUTPUT>

ARGS:
    <INPUT>     The path of uncompressed wasm file to load
    <OUTPUT>    The path of the file where the compressed runtime will be stored

OPTIONS:
    -h, --help       Print help information
    -j, --json       Output as json
    -V, --version    Print version information

Command: decompress

subwasm-decompress 0.17.0
chevdor <[e-mail]>:Wilfried Kopp <[e-mail]
Decompress a given runtime wasm file. You may pass a runtime that is uncompressed already. In that
case, you will get the same content as output. This is useful if you want to decompress "no matter
what" and don't really know whether the input will be compressed or not

USAGE:
    subwasm decompress [OPTIONS] <INPUT> <OUTPUT>

ARGS:
    <INPUT>     The path of the compressed or uncompressed wasm file to load
    <OUTPUT>    The path of the file where the uncompressed runtime will be stored

OPTIONS:
    -h, --help       Print help information
    -j, --json       Output as json
    -V, --version    Print version information

Sample runs

Fetch a runtime from a running node

We will start by fetching the runtime from a node.

Please note that you will likely need to connect to an archive node to retrieve an older runtime (<V11). A runtime takes around 2MB of storage on-chain and thus, older versions are pruned and will no longer be accessible if you are connecting to a non-archive node.

Here we get the latest version of the runtime, the 3 commands do the same since they all use the default values:

subwasm get
subwasm get --url http://localhost:9933
subwasm get --url http://localhost:9933 --output runtime_000.wasm

Here we get an older runtime, back when Polkadot was at block 20 !

subwasm get brew tap chevdor/subwasm --block 0x4d6a0bca208b85d41833a7f35cf73d1ae6974f4bad8ab576e2c3f751d691fe6c

By default, your runtime will be saved as runtime_000.wasm. Running this command again will increase the counter so we you don’t lose your previous runtime. You may also use the --output flag to provide the destination and filename of your choice. Beware, in this case, there will be no incremented counter.

Get quick check of a runtime

# Show the runtime version and exit with status 0
subwasm info --input kusama-2030.wasm

# Provide a few explanations and exit with a status that is not 0
subwasm info --input tictactoe.wasm

Metadata JSON and jq tricks

jq can be used to reprocess the json output. For instance, removing all the documentation from the metadata makes it significantly smaller. The example below shows how to remove documentation, value and default making it much easier on the eyes for human parsing…​

    subwasm --json meta runtime.wasm | jq 'del( .. | .documentation?, .default?, .value? )'

Alternatives

Here is a list of other projects allowing to get the raw metadata through a rpc call:

• PolkadotJS from Jaco / Parity

• subsee from Andrew / Parity

• substrate-api-client from SCS

• subxt from Parity

All those alternatives require a running node and access it via jsonrpc.