ethers-rs/ethers-core/src/utils/ganache.rs

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use std::{
process::{Child, Command},
time::Duration,
};
const SLEEP_TIME: Duration = Duration::from_secs(3);
/// A ganache CLI instance. Will close the instance when dropped.
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///
/// Construct this using [`Ganache`](crate::utils::Ganache)
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pub struct GanacheInstance(Child);
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impl Drop for GanacheInstance {
fn drop(&mut self) {
self.0.kill().expect("could not kill ganache");
}
}
/// Builder for launching `ganache-cli`.
///
/// # Panics
///
/// If `spawn` is called without `ganache-cli` being available in the user's $PATH
///
/// # Example
///
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/// ```no_run
/// use ethers::utils::Ganache;
///
/// let port = 8545u64;
/// let url = format!("http://localhost:{}", port).to_string();
///
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/// let ganache = Ganache::new()
/// .port(port)
/// .mnemonic("abstract vacuum mammal awkward pudding scene penalty purchase dinner depart evoke puzzle")
/// .spawn();
///
/// drop(ganache); // this will kill the instance
/// ```
#[derive(Clone, Default)]
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pub struct Ganache {
port: Option<u64>,
block_time: Option<u64>,
mnemonic: Option<String>,
}
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impl Ganache {
/// Creates an empty Ganache builder.
/// The default port is 8545. The mnemonic is chosen randomly.
pub fn new() -> Self {
Self::default()
}
/// Sets the port which will be used when the `ganache-cli` instance is launched.
pub fn port<T: Into<u64>>(mut self, port: T) -> Self {
self.port = Some(port.into());
self
}
/// Sets the mnemonic which will be used when the `ganache-cli` instance is launched.
pub fn mnemonic<T: Into<String>>(mut self, mnemonic: T) -> Self {
self.mnemonic = Some(mnemonic.into());
self
}
/// Sets the block-time which will be used when the `ganache-cli` instance is launched.
pub fn block_time<T: Into<u64>>(mut self, block_time: T) -> Self {
self.block_time = Some(block_time.into());
self
}
/// Consumes the builder and spawns `ganache-cli` with stdout redirected
/// to /dev/null. This takes ~2 seconds to execute as it blocks while
/// waiting for `ganache-cli` to launch.
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pub fn spawn(self) -> GanacheInstance {
let mut cmd = Command::new("ganache-cli");
cmd.stdout(std::process::Stdio::null());
if let Some(port) = self.port {
cmd.arg("-p").arg(port.to_string());
}
if let Some(mnemonic) = self.mnemonic {
cmd.arg("-m").arg(mnemonic);
}
if let Some(block_time) = self.block_time {
cmd.arg("-b").arg(block_time.to_string());
}
let ganache_pid = cmd.spawn().expect("couldnt start ganache-cli");
// wait a couple of seconds for ganache to boot up
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std::thread::sleep(SLEEP_TIME);
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GanacheInstance(ganache_pid)
}
}