feat(vault): Lend Token collateral #447

daniel-savu · 2023-02-10T17:47:56Z

Adds the ability to run vaults with a lend token currency (e.g. QKSM, QUSDT). The client reads current lending markets from storage to determine the (underlying, lend_token) pairs and then listens for NewMarketEvent and UpdatedMarketEvent to keep the pairs up-to-date.

After some investigation with @sander2, it turns out that all keys from storage maps that use the Blake2_128Concat hasher have a 48 byte prefix than needs to be removed to decode the key. This can replace the way keys are decoded throughout the repo (for instance, in get_foreign_assets_metadata), and doing that would also allow for reusing a single key-decoding function.

This PR was tested on wss://kintnet-api.interlay.io/parachain with QKSM, QUSDT and QKBTC to ensure the client succesfully registers the vault and generates a bitcoin wallet.

Closes: #450

runtime/src/rpc.rs

gregdhill · 2023-02-16T15:34:08Z

runtime/src/assets.rs

@@ -83,6 +150,11 @@ impl TryFromSymbol for CurrencyId {
            id if id == KSM.symbol() => Ok(Token(KSM)),
            id if id == KBTC.symbol() => Ok(Token(KBTC)),
            id if id == KINT.symbol() => Ok(Token(KINT)),
+            // Does the first character match the lend token prefix?
+            id if id.chars().next() == Some(LEND_TOKEN_SYMBOL_PREFIX) => {


The unfortunate problem with this is that parsing would fail if we were to register any other asset which begins with Q, we should somehow always fall-through to get_foreign_asset_by_symbol.

Found a pretty neat solution using an if-let match guard. This feature is experimental however - no bugs have been reported but it's just not well-documented enough: rust-lang/rust#51114 (the issue thread was active within the last month).

gregdhill · 2023-02-16T15:35:44Z

runtime/src/assets.rs

+const LEND_TOKEN_SYMBOL_PREFIX: char = 'Q';
+/// The name of Lend Tokens is the name of their underlying currency,
+/// prefixed by `Lend`. Example: `LendPolkadot` is the `Polkadot` lend token name.
+const LEND_TOKEN_NAME_PREFIX: &str = "Lend";


Is the name used anywhere? The symbol is used parsing at startup, but just wondering if we also need to add the prefix if the name() is used.

It's used to make Coingecko API calls, so not directly relevant but thought it's better to have an implementation than to panic

But we have the coingecko_id for that..? Also, why is coingecko used at all? Or is it within the oracle?

runtime/src/assets.rs

sander2 · 2023-02-17T11:12:05Z

runtime/src/rpc.rs

+/// `twox_128("PalletName") ++ twox_128("ItemName") ++ Blake2_128Concat(key) ++ key`
+/// So to get the actual value of the key from a raw key, we need to ignore the first
+/// `3 * 128 / 8` bytes, or `48` bytes.
+const STORAGE_KEY_HASH_PREFIX_LENGTH: usize = 48;


can you also use this for the existing decodings?

sander2 · 2023-02-17T11:13:32Z

runtime/src/rpc.rs

+/// Keys in storage maps are prefixed by two `twox_128` hashes: the pallet name and the
+/// storage item names. Then, assuming the map uses the `Blake2_128Concat` hasher, the layout
+/// looks as follows:
+/// `twox_128("PalletName") ++ twox_128("ItemName") ++ Blake2_128Concat(key) ++ key`


Suggested change

/// `twox_128("PalletName") ++ twox_128("ItemName") ++ Blake2_128Concat(key) ++ key`

/// `twox_128("PalletName") ++ twox_128("ItemName") ++ Blake2(key) ++ key`

Nit: I think Blake2_128Concat means Blake2(key) ++ key so key would be in there twice

Yep: https://docs.rs/frame-support/latest/frame_support/struct.Blake2_128Concat.html

Turns out that AssetRegistry::Metadata is hashed with Twox64Concat :(

Added a separate decoding function for that hasher

daniel-savu · 2023-02-20T14:30:11Z

runtime/src/assets.rs

+
+    pub(crate) fn insert(underlying_id: CurrencyId, lend_token_id: CurrencyId) -> Result<(), Error> {
+        log::info!(
+            "Found loans market: {:?}, with lend token: {:?}",


FYI this prints the full struct rather than the ticker, because the concurrent listener might run before the foreign asset listener

sander2 · 2023-02-21T14:51:57Z

runtime/src/rpc.rs

@@ -663,24 +790,54 @@ impl UtilFuncs for InterBtcParachain {
        &vault_id.account_id == self.get_account_id()
    }

-    async fn get_foreign_assets_metadata(&self) -> Result<Vec<(u32, AssetMetadata)>, Error> {
+    async fn get_decoded_storage_keys<T, U, F>(


I don't think this should be a trait function - I think this should be a private function in the impl InterBtcParachain, just like other internal utility functions like with_unique_signer

sander2 · 2023-02-21T14:57:05Z

runtime/src/rpc.rs

+    ))]
+    async fn get_lend_tokens(&self) -> Result<Vec<(CurrencyId, CurrencyId)>, Error>;
+
+    async fn get_decoded_storage_keys<T, U, F>(


I'd probably not have this take a callback function, but rather an enum and have the logic inside this function. Not a huge deal if you want to keep the callback, but if so, please make it return a Result, since &raw_key[BLAKE2_128_HASH_PREFIX_LENGTH..] will panic if the input slice is shorter than expected

You mean an enum with the hasher type of the storage key?

feat(vault): Lend Token collateral

4122560

daniel-savu marked this pull request as draft February 10, 2023 17:48

daniel-savu added 3 commits February 13, 2023 17:49

feat(loans): read lend tokens from storage

f3a9a25

fix(vault): loans markets key decoding

bc7c022

feat(runtime): name, symbol, decimals for lend tokens

2facff4

daniel-savu force-pushed the vault-lend-tokens branch from aebb262 to 40ec9d5 Compare February 15, 2023 12:56

fix(runtime): qtoken parsing test

81399f5

daniel-savu force-pushed the vault-lend-tokens branch from 6df3a75 to 81399f5 Compare February 16, 2023 11:50

chore(runtime): refactor lend token prefixes

831c0ee

daniel-savu changed the title ~~WIP(vault): Lend Token collateral~~ feat(vault): Lend Token collateral Feb 16, 2023

daniel-savu marked this pull request as ready for review February 16, 2023 13:13

fix(runtime): lend token parsing clippy warning

bfddbfc

daniel-savu force-pushed the vault-lend-tokens branch from 3e4b2d3 to bfddbfc Compare February 16, 2023 13:21

chore: bump cargo lock

6d6bc79

daniel-savu requested review from gregdhill and sander2 February 16, 2023 13:32

gregdhill reviewed Feb 16, 2023

View reviewed changes

fix(runtime): keep matching if symbol is not lend token

a739d37

sander2 reviewed Feb 17, 2023

View reviewed changes

runtime/src/assets.rs Outdated Show resolved Hide resolved

sander2 reviewed Feb 17, 2023

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daniel-savu added 2 commits February 17, 2023 13:36

chore(runtime): remove name() currency trait fn

a9e2fda

chore(runtime): refactor stoeage key decoding

46f13d4

daniel-savu force-pushed the vault-lend-tokens branch from 547eda3 to 46f13d4 Compare February 20, 2023 12:56

daniel-savu added 2 commits February 20, 2023 14:28

fix: compilation flags for qtoken vault

49b7676

chore: fix mock errors

e004a4b

daniel-savu commented Feb 20, 2023

View reviewed changes

gregdhill approved these changes Feb 20, 2023

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daniel-savu requested a review from sander2 February 20, 2023 16:25

sander2 reviewed Feb 21, 2023

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chore(runtime): simplify get_decoded_storage_keys signature

fb6117d

sander2 approved these changes Feb 22, 2023

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sander2 merged commit 1f871fd into interlay:master Feb 22, 2023

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feat(vault): Lend Token collateral #447

feat(vault): Lend Token collateral #447

daniel-savu commented Feb 10, 2023 •

edited

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gregdhill Feb 16, 2023

daniel-savu Feb 16, 2023

gregdhill Feb 16, 2023

daniel-savu Feb 16, 2023 •

edited by sander2

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sander2 Feb 17, 2023

sander2 Feb 17, 2023

daniel-savu Feb 17, 2023

daniel-savu Feb 17, 2023

daniel-savu Feb 20, 2023

daniel-savu Feb 20, 2023

sander2 Feb 21, 2023

sander2 Feb 21, 2023

daniel-savu Feb 21, 2023

sander2 Feb 22, 2023

	/// `twox_128("PalletName") ++ twox_128("ItemName") ++ Blake2_128Concat(key) ++ key`
	/// `twox_128("PalletName") ++ twox_128("ItemName") ++ Blake2(key) ++ key`

feat(vault): Lend Token collateral #447

feat(vault): Lend Token collateral #447

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daniel-savu commented Feb 10, 2023 • edited Loading

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daniel-savu commented Feb 10, 2023 •

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daniel-savu Feb 16, 2023 •

edited by sander2

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