Add DevnetProvider (#3760)

<!-- Reference any GitHub issues resolved by this PR -->

## Introduced changes

Towards #3603 

**Stack**:
- #3762
- #3761
- #3760 ⬅

## Checklist

<!-- Make sure all of these are complete -->

- [x] Linked relevant issue
- [ ] Updated relevant documentation
- [x] Added relevant tests
- [x] Performed self-review of the code
- [ ] Added changes to `CHANGELOG.md`

---------

Co-authored-by: Artur Michalek <[email protected]>
Co-authored-by: Artur Michałek <[email protected]>

Author: franciszekjob

crates/sncast/src/helpers/devnet_provider.rs

@@ -0,0 +1,130 @@
+use crate::AccountData;
+use ::serde::{Deserialize, Serialize, de::DeserializeOwned};
+use anyhow::{Context, Error, ensure};
+use reqwest::Client;
+use serde_json::json;
+use starknet_types_core::felt::Felt;
+use url::Url;
+
+/// A Devnet-RPC client.
+#[derive(Debug, Clone)]
+pub struct DevnetProvider {
+    client: Client,
+    url: Url,
+}
+
+/// All Devnet-RPC methods as listed in the official docs.
+#[derive(Debug, Clone, Copy, Serialize, Deserialize)]
+pub enum DevnetProviderMethod {
+    #[serde(rename = "devnet_getConfig")]
+    GetConfig,
+
+    #[serde(rename = "devnet_getPredeployedAccounts")]
+    GetPredeployedAccounts,
+}
+
+impl DevnetProvider {
+    #[must_use]
+    pub fn new(url: &str) -> Self {
+        let url = Url::parse(url).expect("Invalid URL");
+        Self {
+            client: Client::new(),
+            url,
+        }
+    }
+}
+
+impl DevnetProvider {
+    async fn send_request<P, R>(&self, method: DevnetProviderMethod, params: P) -> anyhow::Result<R>
+    where
+        P: Serialize + Send + Sync,
+        R: DeserializeOwned,
+    {
+        let res = self
+            .client
+            .post(self.url.clone())
+            .header("Content-Type", "application/json")
+            .json(&json!({
+                "jsonrpc": "2.0",
+                "method": method,
+                "params": params,
+                "id": 1,
+            }))
+            .send()
+            .await
+            .context("Failed to send request")?
+            .json::<serde_json::Value>()
+            .await
+            .context("Failed to parse response")?;
+
+        if let Some(error) = res.get("error") {
+            Err(anyhow::anyhow!(error.to_string()))
+        } else if let Some(result) = res.get("result") {
+            serde_json::from_value(result.clone()).map_err(anyhow::Error::from)
+        } else {
+            panic!("Malformed RPC response: {res}")
+        }
+    }
+
+    /// Fetches the current Devnet configuration.
+    pub async fn get_config(&self) -> Result<Config, Error> {
+        self.send_request(DevnetProviderMethod::GetConfig, json!({}))
+            .await
+    }
+
+    /// Fetches the list of predeployed accounts in Devnet.
+    pub async fn get_predeployed_accounts(&self) -> Result<Vec<PredeployedAccount>, Error> {
+        self.send_request(DevnetProviderMethod::GetPredeployedAccounts, json!({}))
+            .await
+    }
+
+    /// Ensures the Devnet instance is alive.
+    pub async fn ensure_alive(&self) -> Result<(), Error> {
+        let is_alive = self
+            .client
+            .get(format!(
+                "{}/is_alive",
+                self.url.to_string().replace("/rpc", "")
+            ))
+            .send()
+            .await
+            .map(|res| res.status().is_success())
+            .unwrap_or(false);
+
+        ensure!(
+            is_alive,
+            "Node at {} is not responding to the Devnet health check (GET `/is_alive`). It may not be a Devnet instance or it may be down.",
+            self.url
+        );
+        Ok(())
+    }
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct Config {
+    pub seed: u32,
+    pub account_contract_class_hash: Felt,
+    pub total_accounts: u8,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct PredeployedAccount {
+    pub address: Felt,
+    pub private_key: Felt,
+    pub public_key: Felt,
+}
+
+impl From<&PredeployedAccount> for AccountData {
+    fn from(predeployed_account: &PredeployedAccount) -> Self {
+        Self {
+            address: Some(predeployed_account.address),
+            private_key: predeployed_account.private_key,
+            public_key: predeployed_account.public_key,
+            class_hash: None,
+            salt: None,
+            deployed: None,
+            legacy: None,
+            account_type: None,
+        }
+    }
+}

crates/sncast/src/helpers/mod.rs

@@ -5,6 +5,7 @@ pub mod command;
 pub mod config;
 pub mod configuration;
 pub mod constants;
+pub mod devnet_provider;
 pub mod fee;
 pub mod interactive;
 pub mod output_format;

crates/sncast/tests/helpers/constants.rs

@@ -8,10 +8,11 @@ pub const SEPOLIA_RPC_URL: &str = "http://188.34.188.184:7070/rpc/v0_9";
 
 pub const URL: &str = "http://127.0.0.1:5055/rpc";
 pub const NETWORK: &str = "testnet";
-pub const SEED: u32 = 1_053_545_548;
+pub const DEVNET_SEED: u32 = 1_053_545_548;
+pub const DEVNET_ACCOUNTS_NUMBER: u8 = 20;
 
 // Block number used by devnet to fork the Sepolia testnet network in the tests
-pub const FORK_BLOCK_NUMBER: u32 = 721_720;
+pub const DEVNET_FORK_BLOCK_NUMBER: u32 = 721_720;
 
 pub const CONTRACTS_DIR: &str = "tests/data/contracts";
 pub const SCRIPTS_DIR: &str = "tests/data/scripts";

crates/sncast/tests/helpers/devnet.rs

@@ -1,4 +1,6 @@
-use crate::helpers::constants::{FORK_BLOCK_NUMBER, SEED, SEPOLIA_RPC_URL, URL};
+use crate::helpers::constants::{
+    DEVNET_ACCOUNTS_NUMBER, DEVNET_FORK_BLOCK_NUMBER, DEVNET_SEED, SEPOLIA_RPC_URL, URL,
+};
 use crate::helpers::fixtures::{
     deploy_braavos_account, deploy_cairo_0_account, deploy_keystore_account,
     deploy_latest_oz_account, deploy_ready_account,
@@ -39,17 +41,17 @@ fn start_devnet() {
             "--port",
             &port,
             "--seed",
-            &SEED.to_string(),
+            &DEVNET_SEED.to_string(),
             "--state-archive-capacity",
             "full",
             "--fork-network",
             SEPOLIA_RPC_URL,
             "--fork-block",
-            &FORK_BLOCK_NUMBER.to_string(),
+            &DEVNET_FORK_BLOCK_NUMBER.to_string(),
             "--initial-balance",
             "9999999999999999999999999999999",
             "--accounts",
-            "20",
+            &DEVNET_ACCOUNTS_NUMBER.to_string(),
         ])
         .stdout(Stdio::null())
         .spawn()
@@ -80,7 +82,7 @@ fn start_devnet() {
 #[dtor]
 fn stop_devnet() {
     let port = Url::parse(URL).unwrap().port().unwrap_or(80).to_string();
-    let pattern = format!("starknet-devnet.*{port}.*{SEED}");
+    let pattern = format!("starknet-devnet.*{port}.*{DEVNET_SEED}");
 
     Command::new("pkill")
         .args(["-f", &pattern])

crates/sncast/tests/helpers/devnet_provider.rs

@@ -0,0 +1,51 @@
+use crate::helpers::constants::{DEVNET_ACCOUNTS_NUMBER, DEVNET_SEED, SEPOLIA_RPC_URL, URL};
+use num_traits::ToPrimitive;
+use sncast::helpers::{constants::OZ_CLASS_HASH, devnet_provider::DevnetProvider};
+
+#[tokio::test]
+async fn test_get_config() {
+    let devnet_provider = DevnetProvider::new(URL);
+    let config = devnet_provider
+        .get_config()
+        .await
+        .expect("Failed to get config");
+
+    assert!(config.account_contract_class_hash == OZ_CLASS_HASH);
+    assert!(config.seed == DEVNET_SEED);
+    assert!(config.total_accounts == DEVNET_ACCOUNTS_NUMBER);
+}
+
+#[tokio::test]
+async fn test_get_predeployed_accounts() {
+    let devnet_provider = DevnetProvider::new(URL);
+    let predeployed_accounts = devnet_provider
+        .get_predeployed_accounts()
+        .await
+        .expect("Failed to get predeployed accounts");
+
+    assert!(predeployed_accounts.len().to_u8().unwrap() == DEVNET_ACCOUNTS_NUMBER);
+}
+
+#[tokio::test]
+async fn test_is_alive_happy_case() {
+    let devnet_provider = DevnetProvider::new(URL);
+    devnet_provider
+        .ensure_alive()
+        .await
+        .expect("Failed to ensure the devnet is alive");
+}
+
+#[tokio::test]
+async fn test_is_alive_fails_on_sepolia_node() {
+    let devnet_provider = DevnetProvider::new(SEPOLIA_RPC_URL);
+    let res = devnet_provider.ensure_alive().await;
+    assert!(res.is_err(), "Expected an error");
+
+    let err = res.unwrap_err().to_string();
+    assert!(
+        err == format!(
+            "Node at {SEPOLIA_RPC_URL} is not responding to the Devnet health check (GET `/is_alive`). It may not be a Devnet instance or it may be down."
+        ),
+        "Unexpected error message: {err}"
+    );
+}

crates/sncast/tests/helpers/mod.rs

@@ -1,5 +1,6 @@
 pub mod constants;
 pub mod devnet;
+pub mod devnet_provider;
 pub mod env;
 pub mod fee;
 pub mod fixtures;