Struct sc_rpc_api::state::StateClient

pub struct StateClient<Hash> { /* fields omitted */ }

The Client.

Implementations

impl<Hash> Client<Hash> where
    Hash: Send + Sync + 'static + DeserializeOwned + Serialize, 

pub fn new(sender: RpcChannel) -> Self

Creates a new Client.

pub fn call(
    &self,
    name: String,
    bytes: Bytes,
    hash: Option<Hash>
) -> impl Future<Item = Bytes, Error = RpcError>

Call a contract at a block’s state.

pub fn storage_keys(
    &self,
    prefix: StorageKey,
    hash: Option<Hash>
) -> impl Future<Item = Vec<StorageKey>, Error = RpcError>

DEPRECATED: Please use state_getKeysPaged with proper paging support. Returns the keys with prefix, leave empty to get all the keys.

pub fn storage_pairs(
    &self,
    prefix: StorageKey,
    hash: Option<Hash>
) -> impl Future<Item = Vec<(StorageKey, StorageData)>, Error = RpcError>

Returns the keys with prefix, leave empty to get all the keys

pub fn storage_keys_paged(
    &self,
    prefix: Option<StorageKey>,
    count: u32,
    start_key: Option<StorageKey>,
    hash: Option<Hash>
) -> impl Future<Item = Vec<StorageKey>, Error = RpcError>

Returns the keys with prefix with pagination support. Up to count keys will be returned. If start_key is passed, return next keys in storage in lexicographic order.

pub fn storage(
    &self,
    key: StorageKey,
    hash: Option<Hash>
) -> impl Future<Item = Option<StorageData>, Error = RpcError>

Returns a storage entry at a specific block’s state.

pub fn storage_hash(
    &self,
    key: StorageKey,
    hash: Option<Hash>
) -> impl Future<Item = Option<Hash>, Error = RpcError>

Returns the hash of a storage entry at a block’s state.

pub fn storage_size(
    &self,
    key: StorageKey,
    hash: Option<Hash>
) -> impl Future<Item = Option<u64>, Error = RpcError>

Returns the size of a storage entry at a block’s state.

pub fn metadata(
    &self,
    hash: Option<Hash>
) -> impl Future<Item = Bytes, Error = RpcError>

Returns the runtime metadata as an opaque blob.

pub fn runtime_version(
    &self,
    hash: Option<Hash>
) -> impl Future<Item = RuntimeVersion, Error = RpcError>

Get the runtime version.

pub fn query_storage(
    &self,
    keys: Vec<StorageKey>,
    block: Hash,
    hash: Option<Hash>
) -> impl Future<Item = Vec<StorageChangeSet<Hash>>, Error = RpcError>

Query historical storage entries (by key) starting from a block given as the second parameter.

NOTE This first returned result contains the initial state of storage for all keys. Subsequent values in the vector represent changes to the previous state (diffs).

pub fn query_storage_at(
    &self,
    keys: Vec<StorageKey>,
    at: Option<Hash>
) -> impl Future<Item = Vec<StorageChangeSet<Hash>>, Error = RpcError>

Query storage entries (by key) starting at block hash given as the second parameter.

pub fn read_proof(
    &self,
    keys: Vec<StorageKey>,
    hash: Option<Hash>
) -> impl Future<Item = ReadProof<Hash>, Error = RpcError>

Returns proof of storage entries at a specific block’s state.

pub fn trace_block(
    &self,
    block: Hash,
    targets: Option<String>,
    storage_keys: Option<String>
) -> impl Future<Item = TraceBlockResponse, Error = RpcError>

The state_traceBlock RPC provides a way to trace the re-execution of a single block, collecting Spans and Events from both the client and the relevant WASM runtime. The Spans and Events are conceptually equivalent to those from the Tracing crate.

The structure of the traces follows that of the block execution pipeline, so meaningful interpretation of the traces requires an understanding of the Substrate chain’s block execution.

Link to conceptual map of trace structure for Polkadot and Kusama block execution.

Node requirements

• Fully synced archive node (i.e. a node that is not actively doing a “major” sync).
• Tracing enabled WASM runtimes for all runtime versions for which tracing is desired.

Node recommendations

• Use fast SSD disk storage.
• Run node flags to increase DB read speed (i.e. --state-cache-size, --db-cache).

Creating tracing enabled WASM runtimes

• Checkout commit of chain version to compile with WASM traces
• diener can help to peg commit of substrate to what the chain expects.
• Navigate to the runtime folder/package of the chain
• Add feature with-tracing = ["frame-executive/with-tracing", "sp-io/with-tracing"] under [features] to the runtime packages’ Cargo.toml.
• Compile the runtime with cargo build --release --features with-tracing
• Tracing-enabled WASM runtime should be found in ./target/release/wbuild/{{chain}}-runtime and be called something like {{your_chain}}_runtime.compact.wasm. This can be renamed/modified however you like, as long as it retains the .wasm extension.
• Run the node with the wasm blob overrides by placing them in a folder with all your runtimes, and passing the path of this folder to your chain, e.g.:
• ./target/release/polkadot --wasm-runtime-overrides /home/user/my-custom-wasm-runtimes

You can also find some pre-built tracing enabled wasm runtimes in substrate-archive

Source.

RPC Usage

The RPC allows for two filtering mechanisms: tracing targets and storage key prefixes. The filtering of spans and events takes place after they are all collected; so while filters do not reduce time for actual block re-execution, they reduce the response payload size.

Note: storage events primarily come from primitives/state-machine/src/ext.rs. The default filters can be overridden, see the params section for details.

curl example

curl \
	-H "Content-Type: application/json" \
	-d '{"id":1, "jsonrpc":"2.0", "method": "state_traceBlock", \
		"params": ["0xb246acf1adea1f801ce15c77a5fa7d8f2eb8fed466978bcee172cc02cf64e264"]}' \
	http://localhost:9933/

Params

• block_hash (param index 0): Hash of the block to trace.
• targets (param index 1): String of comma separated (no spaces) targets. Specified targets match with trace targets by prefix (i.e if a target is in the beginning of a trace target it is considered a match). If an empty string is specified no targets will be filtered out. The majority of targets correspond to Rust module names, and the ones that do not are typically “hardcoded” into span or event location somewhere in the Substrate source code. (“Non-hardcoded” targets typically come from frame support macros.)
• storage_keys (param index 2): String of comma separated (no spaces) hex encoded (no 0x prefix) storage keys. If an empty string is specified no events will be filtered out. If anything other than an empty string is specified, events will be filtered by storage key (so non-storage events will not show up). You can specify any length of a storage key prefix (i.e. if a specified storage key is in the beginning of an events storage key it is considered a match). Example: for balance tracking on Polkadot & Kusama you would likely want to track changes to account balances with the frame_system::Account storage item, which is a map from AccountId to AccountInfo. The key filter for this would be the storage prefix for the map: 26aa394eea5630e07c48ae0c9558cef7b99d880ec681799c0cf30e8886371da9

Additionally you would want to track the extrinsic index, which is under the :extrinsic_index key. The key for this would be the aforementioned string as bytes in hex: 3a65787472696e7369635f696e646578. The following are some resources to learn more about storage keys in substrate: substrate storage, transparent keys in substrate, querying substrate storage via rpc.

Maximum payload size

The maximum payload size allowed is 15mb. Payloads over this size will return a object with a simple error message. If you run into issues with payload size you can narrow down the traces using a smaller set of targets and/or storage keys.

If you are having issues with maximum payload size you can use the flag -lstate_tracing=trace to get some logging during tracing.

pub fn subscribe_storage(
    &self,
    keys: Option<Vec<StorageKey>>
) -> impl Future<Item = TypedSubscriptionStream<StorageChangeSet<Hash>>, Error = RpcError>

New storage subscription

pub fn subscribe_runtime_version(
    &self
) -> impl Future<Item = TypedSubscriptionStream<RuntimeVersion>, Error = RpcError>

New runtime version subscription

Trait Implementations

impl<Hash: Clone> Clone for Client<Hash>

fn clone(&self) -> Client<Hash>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<Hash> From<RpcChannel> for Client<Hash> where
    Hash: Send + Sync + 'static + DeserializeOwned + Serialize, 

fn from(channel: RpcChannel) -> Self

Performs the conversion.