subwasm

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. You may however want to inspect a runtime that was not deployed yet to any node.

subwasm can work offline on wasm files without any node or internet connectivity.

Capabilities & features

subwasm can:

get the metadata from a a wasm file directly (no need for a node): command get
show summary information and version of a runtime: commands info and version)
diff between two runtime to help users spot changes and difference: command diff
show the list of pallets and their content (calls, events, errors, storage, constants): command show
analyze 2 runtimes to figure out whether they are compatible and if the transaction_version needs to be bumped: command diff
compress and decompress a runtime WASM: commands compress and decompress
get the latest metadata from a running node: command get
fetch the latest runtime (wasm) from a running node: command get
get runtime and metadata at any point of time using a Block hash as reference: command get
do all of the above with an output for human or as json

Demos

Get a runtime

subwasm get

info command

subwasm info

show command

subwasm show

meta command

subwasm meta

diff command

subwasm diff

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` allows fetching, parsing and calling some methods on WASM runtimes of Substrate based chains

Usage: subwasm [OPTIONS] [COMMAND]

Commands:
  get         Get/Download the runtime wasm from a running node through rpc
  info        Shows information about a given runtime
  version     Shows information about a given runtime
  metadata    Returns the metadata of the given runtime in several format. You may also use the "meta" alias
  show        Shows the a reduced view of the runtime
  diff        Compare 2 runtimes after converting them to `[ReducedRuntime]`s
  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 already uncompressed
  help        Print this message or the help of the given subcommand(s)

Options:
  -v, --version   Show the version
  -j, --json      Output as json
  -n, --no-color  Do not write color information to the output. This is recommended for scripts [env: NO_COLOR=]
  -q, --quiet     Less output
  -h, --help      Print help

Command: get

Get/Download the runtime wasm from a running node through rpc

Usage: subwasm get [OPTIONS] [RPC_URL]

Arguments:
  [RPC_URL]
          The node url including (mandatory) the port number. Example: ws://localhost:9944 or http://localhost:9933

Options:
  -c, --chain <CHAIN>
          Provide the name of a chain or an alias.

          If you pass a valid --chain, --rpc_url will be ignored --chain local = http://localhost:9933

  -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.

  -u, --url <URL>
          Load the wasm from a URL (no node) such as <https://github.com/paritytech/polkadot/releases/download/v0.9.42/polkadot_runtime-v9420.compact.compressed.wasm>

  -g, --github <GITHUB>
          Load the wasm from Github passing a string in the format `<runtime>@<version>` such as `kusama@0.9.42`

  -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.

  -j, --json
          Output as json

  -n, --no-color
          Do not write color information to the output. This is recommended for scripts

          [env: NO_COLOR=]

  -q, --quiet
          Less output

  -h, --help
          Print help (see a summary with '-h')

Command: info

Shows information about a given runtime

Usage: subwasm info [OPTIONS] [FILE]

Arguments:
  [FILE]
          The wasm file to load. It can be a path on your local filesystem such /tmp/runtime.wasm

          You may also fetch the runtime remotely, see `chain` and `url` flags.

Options:
  -c, --chain <CHAIN>
          Load the wasm from an RPC node url such as http://localhost:9933 or ws://localhost:9944, a node alias such as "polkadot" or "dot",

          NOTE: --chain local = http://localhost:9933

  -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

  -u, --url <URL>
          Load the wasm from a URL (no node) such as <https://github.com/paritytech/polkadot/releases/download/v0.9.42/polkadot_runtime-v9420.compact.compressed.wasm>

  -g, --github <GITHUB>
          Load the wasm from Github passing a string in the format `<runtime>@<version>` such as `kusama@0.9.42`

  -j, --json
          Output as json

  -n, --no-color
          Do not write color information to the output. This is recommended for scripts

          [env: NO_COLOR=]

  -q, --quiet
          Less output

  -h, --help
          Print help (see a summary with '-h')

By default, the ID for the Parachain pallet is expected to be 0x01 and the call ID for authorize_upgrade is expected to be 0x03. This default behavior can be overriden by setting the PARACHAIN_PALLET_ID to the ID of your parachain pallet and the AUTHORIZE_UPGRADE_PREFIX to the ID of your choice.

Due to a breaking change to the parachainSystem::authorizeUpgrade extrinsic, a new checkVersion boolean flag is required on chains running on Cumulus v0.9.41 and above. This new behavior is supported by the AUTHORIZE_UPGRADE_CHECK_VERSION env variable, which, if set, is evaluated to true if its value is the string "true", or false` otherwise. If not set, the behavior remains the same as pre-0.9.41.

The new check_spec_version parameter can be provided with the AUTHORIZE_UPGRADE_CHECK_VERSION=true or AUTHORIZE_UPGRADE_CHECK_VERSION=false variable, if needed.

Command: version

Shows information about a given runtime

Usage: subwasm version [OPTIONS] [FILE]

Arguments:
  [FILE]
          The wasm file to load. It can be a path on your local filesystem such /tmp/runtime.wasm

          You may also fetch the runtime remotely, see `chain` and `url` flags.

Options:
  -c, --chain <CHAIN>
          Load the wasm from an RPC node url such as http://localhost:9933 or ws://localhost:9944, a node alias such as "polkadot" or "dot",

          NOTE: --chain local = http://localhost:9933

  -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

  -u, --url <URL>
          Load the wasm from a URL (no node) such as <https://github.com/paritytech/polkadot/releases/download/v0.9.42/polkadot_runtime-v9420.compact.compressed.wasm>

  -g, --github <GITHUB>
          Load the wasm from Github passing a string in the format `<runtime>@<version>` such as `kusama@0.9.42`

  -j, --json
          Output as json

  -n, --no-color
          Do not write color information to the output. This is recommended for scripts

          [env: NO_COLOR=]

  -q, --quiet
          Less output

  -h, --help
          Print help (see a summary with '-h')

Command: meta

Returns the metadata of the given runtime in several format. You may also use the "meta" alias.

If you want to see the content of a runtime, see the `show` sub-command.

Usage: subwasm metadata [OPTIONS] [FILE]

Arguments:
  [FILE]
          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

Options:
  -c, --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

  -u, --url <URL>
          Load the wasm from a URL (no node) such as <https://github.com/paritytech/polkadot/releases/download/v0.9.42/polkadot_runtime-v9420.compact.compressed.wasm>

  -g, --github <GITHUB>
          Load the wasm from Github passing a string in the format `<runtime>@<version>` such as `kusama@0.9.42`

  -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

  -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

  -f, --format <FORMAT>
          You may specify the output format. One of "human", "scale", "json", "json+scale", "hex+scale". If you use the default: human, you may want to check out the "show_reduced" command instead

          [default: human]

  -o, --output <OUTPUT>
          You may specifiy the output filename where the metadata will be saved. Alternatively, you may use `auto` and an appropriate name will be generated according to the `format` your chose

  -j, --json
          Output as json

  -n, --no-color
          Do not write color information to the output. This is recommended for scripts

          [env: NO_COLOR=]

  -q, --quiet
          Less output

  -h, --help
          Print help (see a summary with '-h')

Command: show

Shows the a reduced view of the runtime.

A reduced view makes it much easier to understand the inner workings of a given runtime.

Usage: subwasm show [OPTIONS] [FILE]

Arguments:
  [FILE]
          The runtimwe to analyze

Options:
      --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

  -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

  -u, --url <URL>
          Load the wasm from a URL (no node) such as <https://github.com/paritytech/polkadot/releases/download/v0.9.42/polkadot_runtime-v9420.compact.compressed.wasm>

  -g, --github <GITHUB>
          Load the wasm from Github passing a string in the format `<runtime>@<version>` such as `kusama@0.9.42`

  -p, --pallet <PALLET>
          Show only information related to the provided pallet

  -s, --summary
          The runtime is shown as a table, listing all pallets with their IDs, the count of calls, events, errors, constants and storage items

  -j, --json
          Output as json

  -n, --no-color
          Do not write color information to the output. This is recommended for scripts

          [env: NO_COLOR=]

  -q, --quiet
          Less output

  -h, --help
          Print help (see a summary with '-h')

Command: diff

Compare 2 runtimes after converting them to `[ReducedRuntime]`s.

You must pass exactly 2 runtimes.

Usage: subwasm diff [OPTIONS] <RUNTIME_1> <RUNTIME_2>

Arguments:
  <RUNTIME_1>
          Reference runtime

  <RUNTIME_2>
          Second runtime

Options:
  -j, --json
          Output as json

  -n, --no-color
          Do not write color information to the output. This is recommended for scripts

          [env: NO_COLOR=]

  -q, --quiet
          Less output

  -h, --help
          Print help (see a summary with '-h')

Command: compress

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>

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

Options:
  -j, --json      Output as json
  -n, --no-color  Do not write color information to the output. This is recommended for scripts [env: NO_COLOR=]
  -q, --quiet     Less output
  -h, --help      Print help

Command: decompress

Decompress a given runtime wasm file. You may pass a runtime that is already uncompressed.

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>

Arguments:
  <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:
  -j, --json
          Output as json

  -n, --no-color
          Do not write color information to the output. This is recommended for scripts

          [env: NO_COLOR=]

  -q, --quiet
          Less output

  -h, --help
          Print help (see a summary with '-h')

Environment variables

In addition to the command line flags, you can also pass one of the following ENV variables:

# This is a sample .env file. It is not needed if you
# are using defaults if you want to use the default defined
# below.

# POLKADOT_HTTP=http://localhost:9933
# POLKADOT_WS=ws://localhost:9944
# PARACHAIN_PALLET_ID=0x01
# AUTHORIZE_UPGRADE_PREFIX=0x02

RUST_LOG=subwasm=debug,substrate_differ=trace

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 http://localhost:9933
subwasm get 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 kusama-2030.wasm

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

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README.md

README.md

subwasm

Introduction

Capabilities & features

Demos

Get a runtime

info command

show command

meta command

diff command

Install

Using Cargo

Homebrew

Linux

Usage

Command: --help

Command: get

Command: info

Command: version

Command: meta

Command: show

Command: diff

Command: compress

Command: decompress

Environment variables

Sample runs

Metadata JSON and jq tricks

Alternatives

Files

README.md

Latest commit

History

README.md

File metadata and controls

subwasm

Introduction

Capabilities & features

Demos

Get a runtime

info command

show command

meta command

diff command

Install

Using Cargo

Homebrew

Linux

Usage

Command: --help

Command: get

Command: info

Command: version

Command: meta

Command: show

Command: diff

Command: compress

Command: decompress

Environment variables

Sample runs

Metadata JSON and jq tricks

Alternatives