devimint/

util.rs

use std::collections::BTreeMap;
use std::ffi::OsStr;
use std::future::Future;
use std::ops::ControlFlow;
use std::path::PathBuf;
use std::process::Stdio;
use std::sync::Arc;
use std::time::Duration;
use std::{env, unreachable};

use anyhow::{Context, Result, anyhow, bail, format_err};
use fedimint_core::PeerId;
use fedimint_core::admin_client::SetupStatus;
use fedimint_core::envs::{
    FM_ENABLE_MODULE_LNV2_ENV, FM_ENABLE_MODULE_MINTV2_ENV, FM_ENABLE_MODULE_WALLETV2_ENV,
    is_env_var_set,
};
use fedimint_core::module::ApiAuth;
use fedimint_core::task::{self};
use fedimint_core::time::now;
use fedimint_core::util::FmtCompactAnyhow as _;
use fedimint_core::util::backoff_util::custom_backoff;
use fedimint_logging::LOG_DEVIMINT;
use semver::Version;
use serde::de::DeserializeOwned;
use tokio::fs::OpenOptions;
use tokio::process::Child;
use tokio::sync::Mutex;
use tracing::debug;

use crate::envs::{
    FM_BACKWARDS_COMPATIBILITY_TEST_ENV, FM_BITCOIN_CLI_BASE_EXECUTABLE_ENV,
    FM_BITCOIND_BASE_EXECUTABLE_ENV, FM_BTC_CLIENT_ENV, FM_CLIENT_DIR_ENV,
    FM_DEVIMINT_CMD_INHERIT_STDERR_ENV, FM_DEVIMINT_FAUCET_BASE_EXECUTABLE_ENV,
    FM_ESPLORA_BASE_EXECUTABLE_ENV, FM_FEDIMINT_CLI_BASE_EXECUTABLE_ENV,
    FM_FEDIMINT_DBTOOL_BASE_EXECUTABLE_ENV, FM_FEDIMINTD_BASE_EXECUTABLE_ENV,
    FM_GATEWAY_CLI_BASE_EXECUTABLE_ENV, FM_GATEWAYD_BASE_EXECUTABLE_ENV, FM_GWCLI_LDK_ENV,
    FM_GWCLI_LND_ENV, FM_LNCLI_BASE_EXECUTABLE_ENV, FM_LNCLI_ENV, FM_LND_BASE_EXECUTABLE_ENV,
    FM_LOAD_TEST_TOOL_BASE_EXECUTABLE_ENV, FM_LOGS_DIR_ENV, FM_MINT_CLIENT_ENV,
    FM_RECOVERYTOOL_BASE_EXECUTABLE_ENV, FM_RECURRINGD_BASE_EXECUTABLE_ENV,
};

// If a binary doesn't provide a clap version, default to the first stable
// release (v0.2.1)
const DEFAULT_VERSION: Version = Version::new(0, 2, 1);

pub fn parse_map(s: &str) -> Result<BTreeMap<String, String>> {
    let mut map = BTreeMap::new();

    if s.is_empty() {
        return Ok(map);
    }

    for pair in s.split(',') {
        let parts: Vec<&str> = pair.split('=').collect();
        if parts.len() == 2 {
            map.insert(parts[0].to_string(), parts[1].to_string());
        } else {
            return Err(format_err!("Invalid pair in map: {pair}"));
        }
    }
    Ok(map)
}

use crate::process_reaper;

/// Kills process when all references to ProcessHandle are dropped.
///
/// NOTE: drop order is significant make sure fields in struct are declared in
/// correct order it is generally clients, process handle, deps
#[derive(Debug, Clone)]
pub struct ProcessHandle(Arc<Mutex<ProcessHandleInner>>);

impl ProcessHandle {
    pub async fn terminate(&self) -> Result<()> {
        let mut inner = self.0.lock().await;
        inner.terminate();
        Ok(())
    }

    pub async fn await_terminated(&self) -> Result<()> {
        let mut inner = self.0.lock().await;
        inner.await_terminated().await?;
        Ok(())
    }

    pub async fn is_running(&self) -> bool {
        self.0.lock().await.child.is_some()
    }

    pub async fn id(&self) -> Option<u32> {
        self.0.lock().await.child.as_ref().and_then(Child::id)
    }
}

#[derive(Debug)]
pub struct ProcessHandleInner {
    name: String,
    child: Option<Child>,
}

impl ProcessHandleInner {
    /// Signal and wait for the child to be reaped.
    ///
    /// Blocks synchronously. This matters for:
    /// - explicit `terminate().await` callers that `rm -rf` the data dir right
    ///   after;
    /// - `Drop` at program exit, so children don't outlive `devimint` and race
    ///   post-test cleanup in `fm-run-test`.
    ///
    /// The wait is a plain `CondVar::wait` in the reaper — we never
    /// `block_on` an async fn, so we don't reintroduce the panic-unsafe
    /// executor-stall hazard that motivated this PR.
    fn terminate(&mut self) {
        if let Some(child) = self.child.take() {
            debug!(
                target: LOG_DEVIMINT,
                name = %self.name,
                "killing child process"
            );

            process_reaper::kill_process(&child);
            process_reaper::reap_killed_processes();
        }
    }

    async fn await_terminated(&mut self) -> anyhow::Result<()> {
        match self
            .child
            .as_mut()
            .expect("Process not running")
            .wait()
            .await
        {
            Ok(_status) => {
                debug!(
                    target: LOG_DEVIMINT,
                    name=%self.name,
                    "child process terminated"
                );
            }
            Err(err) => {
                bail!("Failed to wait for child process {}: {}", self.name, err);
            }
        }

        // only drop the child handle if succeeded to terminate
        self.child.take();
        Ok(())
    }
}

impl Drop for ProcessHandleInner {
    fn drop(&mut self) {
        if self.child.is_none() {
            return;
        }

        self.terminate();
    }
}

#[derive(Clone)]
pub struct ProcessManager {
    pub globals: super::vars::Global,
}

impl ProcessManager {
    pub fn new(globals: super::vars::Global) -> Self {
        Self { globals }
    }

    /// Logs to $FM_LOGS_DIR/{name}.{out,err}
    pub async fn spawn_daemon(&self, name: &str, mut cmd: Command) -> Result<ProcessHandle> {
        // Reap any recently killed processes so their resources
        // (ports, file locks) are fully released before we bind new ones.
        process_reaper::reap_killed_processes();
        debug!(target: LOG_DEVIMINT, %name, "Spawning daemon");
        let logs_dir = env::var(FM_LOGS_DIR_ENV)?;
        let path = format!("{logs_dir}/{name}.log");
        let log = OpenOptions::new()
            .append(true)
            .create(true)
            .open(path)
            .await?
            .into_std()
            .await;
        cmd.cmd.kill_on_drop(false); // we handle killing ourself
        cmd.cmd.stdout(log.try_clone()?);
        cmd.cmd.stderr(log);
        let child = cmd
            .cmd
            .spawn()
            .with_context(|| format!("Could not spawn: {name}"))?;
        let handle = ProcessHandle(Arc::new(Mutex::new(ProcessHandleInner {
            name: name.to_owned(),
            child: Some(child),
        })));
        Ok(handle)
    }
}

pub struct Command {
    pub cmd: tokio::process::Command,
    pub args_debug: Vec<String>,
}

impl Command {
    pub fn arg<T: ToString>(mut self, arg: &T) -> Self {
        let string = arg.to_string();
        self.cmd.arg(string.clone());
        self.args_debug.push(string);
        self
    }

    pub fn args<T: ToString>(mut self, args: impl IntoIterator<Item = T>) -> Self {
        for arg in args {
            self = self.arg(&arg);
        }
        self
    }

    pub fn env<K, V>(mut self, key: K, val: V) -> Self
    where
        K: AsRef<OsStr>,
        V: AsRef<OsStr>,
    {
        self.cmd.env(key, val);
        self
    }

    pub fn envs<I, K, V>(mut self, env: I) -> Self
    where
        I: IntoIterator<Item = (K, V)>,
        K: AsRef<OsStr>,
        V: AsRef<OsStr>,
    {
        self.cmd.envs(env);
        self
    }

    pub fn kill_on_drop(mut self, kill: bool) -> Self {
        self.cmd.kill_on_drop(kill);
        self
    }

    /// Run the command and get its output as json.
    pub async fn out_json(&mut self) -> Result<serde_json::Value> {
        Ok(serde_json::from_str(&self.out_string().await?)?)
    }

    fn command_debug(&self) -> String {
        self.args_debug
            .iter()
            .map(|x| x.replace(' ', "␣"))
            .collect::<Vec<_>>()
            .join(" ")
    }

    /// Run the command and get its output as string.
    pub async fn out_string(&mut self) -> Result<String> {
        let output = self
            .run_inner(true)
            .await
            .with_context(|| format!("command: {}", self.command_debug()))?;
        let output = String::from_utf8(output.stdout)?;
        Ok(output.trim().to_owned())
    }

    /// Returns the json error if the command has a non-zero exit code.
    pub async fn expect_err_json(&mut self) -> Result<serde_json::Value> {
        let output = self
            .run_inner(false)
            .await
            .with_context(|| format!("command: {}", self.command_debug()))?;
        let output = String::from_utf8(output.stdout)?;
        Ok(serde_json::from_str(output.trim())?)
    }

    /// Run the command expecting an error, which is parsed using a closure.
    /// Returns an Err if the closure returns false.
    pub async fn assert_error(
        &mut self,
        predicate: impl Fn(serde_json::Value) -> bool,
    ) -> Result<()> {
        let parsed_error = self.expect_err_json().await?;
        anyhow::ensure!(predicate(parsed_error));
        Ok(())
    }

    /// Returns an Err if the command doesn't return an error containing the
    /// provided error string.
    pub async fn assert_error_contains(&mut self, error: &str) -> Result<()> {
        self.assert_error(|err_json| {
            let error_string = err_json
                .get("error")
                .expect("json error contains error field")
                .as_str()
                .expect("not a string")
                .to_owned();

            error_string.contains(error)
        })
        .await
    }

    pub async fn run_inner(&mut self, expect_success: bool) -> Result<std::process::Output> {
        debug!(target: LOG_DEVIMINT, "> {}", self.command_debug());
        let output = self
            .cmd
            .stdout(Stdio::piped())
            .stderr(if is_env_var_set(FM_DEVIMINT_CMD_INHERIT_STDERR_ENV) {
                Stdio::inherit()
            } else {
                Stdio::piped()
            })
            .spawn()?
            .wait_with_output()
            .await?;

        if output.status.success() != expect_success {
            bail!(
                "{}\nstdout:\n{}\nstderr:\n{}\n",
                output.status,
                String::from_utf8_lossy(&output.stdout),
                String::from_utf8_lossy(&output.stderr),
            );
        }
        Ok(output)
    }

    /// Run the command ignoring its output.
    pub async fn run(&mut self) -> Result<()> {
        let _ = self
            .run_inner(true)
            .await
            .with_context(|| format!("command: {}", self.command_debug()))?;
        Ok(())
    }

    /// Run the command logging the output and error
    pub async fn run_with_logging(&mut self, name: String) -> Result<()> {
        let logs_dir = env::var(FM_LOGS_DIR_ENV)?;
        let path = format!("{logs_dir}/{name}.log");
        let log = OpenOptions::new()
            .append(true)
            .create(true)
            .open(&path)
            .await
            .with_context(|| format!("path: {path} cmd: {name}"))?
            .into_std()
            .await;
        self.cmd.stdout(log.try_clone()?);
        self.cmd.stderr(log);
        let status = self
            .cmd
            .spawn()
            .with_context(|| format!("cmd: {name}"))?
            .wait()
            .await?;
        if !status.success() {
            bail!("{status}");
        }
        Ok(())
    }
}

/// easy syntax to create a Command
///
/// `(A1, A2, A3)` expands to
/// ```ignore
/// A1.cmd().await?
///     .arg(A2)
///     .arg(A3)
///     .kill_on_drop(true)
/// ```
///
/// If `An` is a string literal, it is replaced with `format!(a)`
#[macro_export]
macro_rules! cmd {
    ($(@head ($($head:tt)* ))? $curr:literal $(, $($tail:tt)*)?) => {
        cmd! {
            @head ($($($head)*)? format!($curr),)
            $($($tail)*)?
        }
    };
    ($(@head ($($head:tt)* ))? $curr:expr_2021 $(, $($tail:tt)*)?) => {
        cmd! {
            @head ($($($head)*)? $curr,)
            $($($tail)*)?
        }
    };
    (@head ($($head:tt)* )) => {
        cmd! {
            @last
            $($head)*
        }
    };
    // last matcher
    (@last $this:expr_2021, $($arg:expr_2021),* $(,)?) => {
        {
            #[allow(unused)]
            use $crate::util::ToCmdExt;
            $this.cmd()
                $(.arg(&$arg))*
                .kill_on_drop(true)
                .env("RUST_BACKTRACE", "1")
                .env("RUST_LIB_BACKTRACE", "0")
        }
    };
}

#[macro_export]
macro_rules! poll_eq {
    ($left:expr_2021, $right:expr_2021) => {
        match ($left, $right) {
            (left, right) => {
                if left == right {
                    Ok(())
                } else {
                    Err(std::ops::ControlFlow::Continue(anyhow::anyhow!(
                        "assertion failed, left: {left:?} right: {right:?}"
                    )))
                }
            }
        }
    };
}

#[macro_export]
macro_rules! poll_almost_equal {
    ($left:expr_2021, $right:expr_2021) => {
        match ($left, $right) {
            (left, right) => $crate::util::almost_equal(left, right, 1_000_000)
                .map_err(|e| std::ops::ControlFlow::Continue(anyhow::anyhow!(e))),
        }
    };
}

pub fn almost_equal(a: u64, b: u64, max: u64) -> Result<(), String> {
    if a.abs_diff(b) <= max {
        Ok(())
    } else {
        Err(format!(
            "Expected difference is {max} but we found {}",
            a.abs_diff(b)
        ))
    }
}

// Allow macro to be used within the crate. See https://stackoverflow.com/a/31749071.
pub(crate) use cmd;

/// Retry until `f` succeeds or timeout is reached
///
/// - if `f` return Ok(val), this returns with Ok(val).
/// - if `f` return Err(Control::Break(err)), this returns Err(err)
/// - if `f` return Err(ControlFlow::Continue(err)), retries until timeout
///   reached
pub async fn poll_with_timeout<Fut, R>(
    name: &str,
    timeout: Duration,
    f: impl Fn() -> Fut,
) -> Result<R>
where
    Fut: Future<Output = Result<R, ControlFlow<anyhow::Error, anyhow::Error>>>,
{
    const MIN_BACKOFF: Duration = Duration::from_millis(50);
    const MAX_BACKOFF: Duration = Duration::from_secs(1);

    let mut backoff = custom_backoff(MIN_BACKOFF, MAX_BACKOFF, None);
    let start = now();
    for attempt in 0u64.. {
        let attempt_start = now();
        match f().await {
            Ok(value) => return Ok(value),
            Err(ControlFlow::Break(err)) => {
                return Err(err).with_context(|| format!("polling {name}"));
            }
            Err(ControlFlow::Continue(err))
                if attempt_start
                    .duration_since(start)
                    .expect("time goes forward")
                    < timeout =>
            {
                debug!(target: LOG_DEVIMINT, %attempt, err = %err.fmt_compact_anyhow(), "Polling {name} failed, will retry...");
                task::sleep(backoff.next().unwrap_or(MAX_BACKOFF)).await;
            }
            Err(ControlFlow::Continue(err)) => {
                return Err(err).with_context(|| {
                    format!(
                        "Polling {name} failed after {attempt} retries (timeout: {}s)",
                        timeout.as_secs()
                    )
                });
            }
        }
    }

    unreachable!();
}

const DEFAULT_POLL_TIMEOUT: Duration = Duration::from_mins(1);
const EXTRA_LONG_POLL_TIMEOUT: Duration = Duration::from_secs(90);

/// Retry until `f` succeeds or default timeout is reached
///
/// - if `f` return Ok(val), this returns with Ok(val).
/// - if `f` return Err(Control::Break(err)), this returns Err(err)
/// - if `f` return Err(ControlFlow::Continue(err)), retries until timeout
///   reached
pub async fn poll<Fut, R>(name: &str, f: impl Fn() -> Fut) -> Result<R>
where
    Fut: Future<Output = Result<R, ControlFlow<anyhow::Error, anyhow::Error>>>,
{
    poll_with_timeout(
        name,
        if is_env_var_set("FM_EXTRA_LONG_POLL") {
            EXTRA_LONG_POLL_TIMEOUT
        } else {
            DEFAULT_POLL_TIMEOUT
        },
        f,
    )
    .await
}

pub async fn poll_simple<Fut, R>(name: &str, f: impl Fn() -> Fut) -> Result<R>
where
    Fut: Future<Output = Result<R, anyhow::Error>>,
{
    poll(name, || async { f().await.map_err(ControlFlow::Continue) }).await
}

// used to add `cmd` method.
pub trait ToCmdExt {
    fn cmd(self) -> Command;
}

// a command that uses self as program name
impl ToCmdExt for &'_ str {
    fn cmd(self) -> Command {
        Command {
            cmd: tokio::process::Command::new(self),
            args_debug: vec![self.to_owned()],
        }
    }
}

impl ToCmdExt for Vec<String> {
    fn cmd(self) -> Command {
        to_command(self)
    }
}

pub trait JsonValueExt {
    fn to_typed<T: DeserializeOwned>(self) -> Result<T>;
}

impl JsonValueExt for serde_json::Value {
    fn to_typed<T: DeserializeOwned>(self) -> Result<T> {
        Ok(serde_json::from_value(self)?)
    }
}

const GATEWAYD_FALLBACK: &str = "gatewayd";

const FEDIMINTD_FALLBACK: &str = "fedimintd";

const FEDIMINT_CLI_FALLBACK: &str = "fedimint-cli";

pub fn get_fedimint_cli_path() -> Vec<String> {
    get_command_str_for_alias(
        &[FM_FEDIMINT_CLI_BASE_EXECUTABLE_ENV],
        &[FEDIMINT_CLI_FALLBACK],
    )
}

const GATEWAY_CLI_FALLBACK: &str = "gateway-cli";

pub fn get_gateway_cli_path() -> Vec<String> {
    get_command_str_for_alias(
        &[FM_GATEWAY_CLI_BASE_EXECUTABLE_ENV],
        &[GATEWAY_CLI_FALLBACK],
    )
}

const LOAD_TEST_TOOL_FALLBACK: &str = "fedimint-load-test-tool";

const LNCLI_FALLBACK: &str = "lncli";

pub fn get_lncli_path() -> Vec<String> {
    get_command_str_for_alias(&[FM_LNCLI_BASE_EXECUTABLE_ENV], &[LNCLI_FALLBACK])
}

const BITCOIN_CLI_FALLBACK: &str = "bitcoin-cli";

pub fn get_bitcoin_cli_path() -> Vec<String> {
    get_command_str_for_alias(
        &[FM_BITCOIN_CLI_BASE_EXECUTABLE_ENV],
        &[BITCOIN_CLI_FALLBACK],
    )
}

const BITCOIND_FALLBACK: &str = "bitcoind";

const LND_FALLBACK: &str = "lnd";

const ESPLORA_FALLBACK: &str = "esplora";

const RECOVERYTOOL_FALLBACK: &str = "fedimint-recoverytool";

const DEVIMINT_FAUCET_FALLBACK: &str = "devimint";

const FEDIMINT_DBTOOL_FALLBACK: &str = "fedimint-dbtool";

pub fn get_fedimint_dbtool_cli_path() -> Vec<String> {
    get_command_str_for_alias(
        &[FM_FEDIMINT_DBTOOL_BASE_EXECUTABLE_ENV],
        &[FEDIMINT_DBTOOL_FALLBACK],
    )
}

/// Maps a version hash to a release version
fn version_hash_to_version(version_hash: &str) -> Result<Version> {
    match version_hash {
        "a8422b84102ab5fc768307215d5b20d807143f27" => Ok(Version::new(0, 2, 1)),
        "a849377f6466b26bf9b2747242ff01fd4d4a031b" => Ok(Version::new(0, 2, 2)),
        _ => Err(anyhow!("no version known for version hash: {version_hash}")),
    }
}

pub struct FedimintdCmd;
impl FedimintdCmd {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_FEDIMINTD_BASE_EXECUTABLE_ENV],
            &[FEDIMINTD_FALLBACK],
        ))
    }

    /// Returns the fedimintd version from clap or default min version
    pub async fn version_or_default() -> Version {
        match cmd!(FedimintdCmd, "--version").out_string().await {
            Ok(version) => parse_clap_version(&version),
            Err(_) => cmd!(FedimintdCmd, "version-hash")
                .out_string()
                .await
                .map_or(DEFAULT_VERSION, |v| {
                    version_hash_to_version(&v).unwrap_or(DEFAULT_VERSION)
                }),
        }
    }
}

pub struct Gatewayd;
impl Gatewayd {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_GATEWAYD_BASE_EXECUTABLE_ENV],
            &[GATEWAYD_FALLBACK],
        ))
    }

    /// Returns the gatewayd version from clap or default min version
    pub async fn version_or_default() -> Version {
        match cmd!(Gatewayd, "--version").out_string().await {
            Ok(version) => parse_clap_version(&version),
            Err(_) => cmd!(Gatewayd, "version-hash")
                .out_string()
                .await
                .map_or(DEFAULT_VERSION, |v| {
                    version_hash_to_version(&v).unwrap_or(DEFAULT_VERSION)
                }),
        }
    }
}

pub struct FedimintCli;
impl FedimintCli {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_MINT_CLIENT_ENV],
            &get_fedimint_cli_path()
                .iter()
                .map(String::as_str)
                .collect::<Vec<_>>(),
        ))
    }

    /// Returns the fedimint-cli version from clap or default min version
    pub async fn version_or_default() -> Version {
        match cmd!(FedimintCli, "--version").out_string().await {
            Ok(version) => parse_clap_version(&version),
            Err(_) => DEFAULT_VERSION,
        }
    }

    pub async fn set_local_params_leader(
        self,
        peer: &PeerId,
        auth: &ApiAuth,
        endpoint: &str,
        federation_size: Option<usize>,
    ) -> Result<String> {
        let mut command = cmd!(
            self,
            "--password",
            auth.as_str(),
            "admin",
            "setup",
            endpoint,
            "set-local-params",
            format!("Devimint Guardian {peer}"),
            "--federation-name",
            "Devimint Federation",
        );

        if let Some(size) = federation_size {
            command = command.args(["--federation-size", &size.to_string()]);
        }

        let json = command.out_json().await?;

        Ok(serde_json::from_value(json)?)
    }

    pub async fn set_local_params_follower(
        self,
        peer: &PeerId,
        auth: &ApiAuth,
        endpoint: &str,
    ) -> Result<String> {
        let json = cmd!(
            self,
            "--password",
            auth.as_str(),
            "admin",
            "setup",
            endpoint,
            "set-local-params",
            format!("Devimint Guardian {peer}")
        )
        .out_json()
        .await?;

        Ok(serde_json::from_value(json)?)
    }

    pub async fn add_peer(self, params: &str, auth: &ApiAuth, endpoint: &str) -> Result<()> {
        cmd!(
            self,
            "--password",
            auth.as_str(),
            "admin",
            "setup",
            endpoint,
            "add-peer",
            params
        )
        .run()
        .await
    }

    pub async fn setup_status(self, auth: &ApiAuth, endpoint: &str) -> Result<SetupStatus> {
        let json = cmd!(
            self,
            "--password",
            auth.as_str(),
            "admin",
            "setup",
            endpoint,
            "status",
        )
        .out_json()
        .await?;

        Ok(serde_json::from_value(json)?)
    }

    pub async fn start_dkg(self, auth: &ApiAuth, endpoint: &str) -> Result<()> {
        cmd!(
            self,
            "--password",
            auth.as_str(),
            "admin",
            "setup",
            endpoint,
            "start-dkg"
        )
        .run()
        .await
    }

    pub async fn shutdown(self, auth: &ApiAuth, our_id: u64, session_count: u64) -> Result<()> {
        cmd!(
            self,
            "--password",
            auth.as_str(),
            "--our-id",
            our_id,
            "admin",
            "shutdown",
            session_count,
        )
        .run()
        .await
    }

    pub async fn status(self, auth: &ApiAuth, our_id: u64) -> Result<()> {
        cmd!(
            self,
            "--password",
            auth.as_str(),
            "--our-id",
            our_id,
            "admin",
            "status",
        )
        .run()
        .await
    }
}

pub struct LoadTestTool;
impl LoadTestTool {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_LOAD_TEST_TOOL_BASE_EXECUTABLE_ENV],
            &[LOAD_TEST_TOOL_FALLBACK],
        ))
    }
}

pub struct GatewayCli;
impl GatewayCli {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_GATEWAY_CLI_BASE_EXECUTABLE_ENV],
            &get_gateway_cli_path()
                .iter()
                .map(String::as_str)
                .collect::<Vec<_>>(),
        ))
    }

    /// Returns the gateway-cli version from clap or default min version
    pub async fn version_or_default() -> Version {
        match cmd!(GatewayCli, "--version").out_string().await {
            Ok(version) => parse_clap_version(&version),
            Err(_) => DEFAULT_VERSION,
        }
    }
}

pub struct GatewayLndCli;
impl GatewayLndCli {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_GWCLI_LND_ENV],
            &["gateway-lnd"],
        ))
    }
}

pub struct GatewayLdkCli;
impl GatewayLdkCli {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_GWCLI_LDK_ENV],
            &["gateway-ldk"],
        ))
    }
}

pub struct LnCli;
impl LnCli {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_LNCLI_ENV],
            &get_lncli_path()
                .iter()
                .map(String::as_str)
                .collect::<Vec<_>>(),
        ))
    }
}

pub struct BitcoinCli;
impl BitcoinCli {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_BTC_CLIENT_ENV],
            &get_bitcoin_cli_path()
                .iter()
                .map(String::as_str)
                .collect::<Vec<_>>(),
        ))
    }
}

pub struct Bitcoind;
impl Bitcoind {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_BITCOIND_BASE_EXECUTABLE_ENV],
            &[BITCOIND_FALLBACK],
        ))
    }
}

pub struct Lnd;
impl Lnd {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_LND_BASE_EXECUTABLE_ENV],
            &[LND_FALLBACK],
        ))
    }
}

pub struct Esplora;
impl Esplora {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_ESPLORA_BASE_EXECUTABLE_ENV],
            &[ESPLORA_FALLBACK],
        ))
    }
}

pub struct Recoverytool;
impl Recoverytool {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_RECOVERYTOOL_BASE_EXECUTABLE_ENV],
            &[RECOVERYTOOL_FALLBACK],
        ))
    }
}

pub struct DevimintFaucet;
impl DevimintFaucet {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_DEVIMINT_FAUCET_BASE_EXECUTABLE_ENV],
            &[DEVIMINT_FAUCET_FALLBACK],
        ))
    }
}

pub struct Recurringd;
impl Recurringd {
    pub fn cmd(self) -> Command {
        to_command(get_command_str_for_alias(
            &[FM_RECURRINGD_BASE_EXECUTABLE_ENV],
            &["fedimint-recurringd"],
        ))
    }
}

fn get_command_str_for_alias(aliases: &[&str], default: &[&str]) -> Vec<String> {
    // try to use one of the aliases if set
    for alias in aliases {
        if let Ok(cmd) = std::env::var(alias) {
            return cmd.split_whitespace().map(ToOwned::to_owned).collect();
        }
    }
    // otherwise return the default value
    default.iter().map(ToString::to_string).collect()
}

fn to_command(cli: Vec<String>) -> Command {
    let mut cmd = tokio::process::Command::new(&cli[0]);
    cmd.args(&cli[1..]);
    Command {
        cmd,
        args_debug: cli,
    }
}

pub fn supports_lnv2() -> bool {
    std::env::var_os(FM_ENABLE_MODULE_LNV2_ENV).is_none()
        || is_env_var_set(FM_ENABLE_MODULE_LNV2_ENV)
}

pub fn supports_wallet_v2() -> bool {
    is_env_var_set(FM_ENABLE_MODULE_WALLETV2_ENV)
}

pub fn supports_mint_v2() -> bool {
    is_env_var_set(FM_ENABLE_MODULE_MINTV2_ENV)
}

/// Returns true if running backwards-compatibility tests
pub fn is_backwards_compatibility_test() -> bool {
    is_env_var_set(FM_BACKWARDS_COMPATIBILITY_TEST_ENV)
}

/// Sets the fedimint-cli binary to match the fedimintd's version, which is
/// needed for running DKG. Returns the original fedimint-cli path and mint
/// client alias so the caller can reset the fedimint-cli version after DKG
pub async fn use_matching_fedimint_cli_for_dkg() -> Result<(String, String)> {
    let pkg_version = semver::Version::parse(env!("CARGO_PKG_VERSION"))?;
    let fedimintd_version = crate::util::FedimintdCmd::version_or_default().await;
    let original_fedimint_cli_path = crate::util::get_fedimint_cli_path().join(" ");

    if pkg_version == fedimintd_version {
        // we're on the current version if the fedimintd version is the same as the
        // package version. to use the current version of `fedimint-cli` built by cargo,
        // we need to unset FM_FEDIMINT_CLI_BASE_EXECUTABLE
        // TODO: Audit that the environment access only happens in single-threaded code.
        unsafe { std::env::remove_var(FM_FEDIMINT_CLI_BASE_EXECUTABLE_ENV) };
    } else {
        let parsed_fedimintd_version = fedimintd_version.to_string().replace(['-', '.'], "_");

        // matches format defined by nix_binary_version_var_name in scripts/_common.sh
        let fedimint_cli_path_var = format!("fm_bin_fedimint_cli_v{parsed_fedimintd_version}");
        let fedimint_cli_path = std::env::var(fedimint_cli_path_var)?;
        // TODO: Audit that the environment access only happens in single-threaded code.
        unsafe { std::env::set_var(FM_FEDIMINT_CLI_BASE_EXECUTABLE_ENV, fedimint_cli_path) };
    }

    let original_fm_mint_client = std::env::var(FM_MINT_CLIENT_ENV)?;
    let fm_client_dir = std::env::var(FM_CLIENT_DIR_ENV)?;
    let fm_client_dir_path_buf: PathBuf = PathBuf::from(fm_client_dir);

    let fm_mint_client: String = format!(
        "{fedimint_cli} --data-dir {datadir}",
        fedimint_cli = crate::util::get_fedimint_cli_path().join(" "),
        datadir = crate::vars::utf8(&fm_client_dir_path_buf)
    );
    // TODO: Audit that the environment access only happens in single-threaded code.
    unsafe { std::env::set_var(FM_MINT_CLIENT_ENV, fm_mint_client) };

    Ok((original_fedimint_cli_path, original_fm_mint_client))
}

/// Sets the fedimint-cli and mint client alias
pub fn use_fedimint_cli(original_fedimint_cli_path: String, original_fm_mint_client: String) {
    // TODO: Audit that the environment access only happens in single-threaded code.
    unsafe {
        std::env::set_var(
            FM_FEDIMINT_CLI_BASE_EXECUTABLE_ENV,
            original_fedimint_cli_path,
        );
    };

    // TODO: Audit that the environment access only happens in single-threaded code.
    unsafe { std::env::set_var(FM_MINT_CLIENT_ENV, original_fm_mint_client) };
}

/// Parses a version string returned from clap
/// ex: fedimintd 0.3.0-alpha -> 0.3.0-alpha
fn parse_clap_version(res: &str) -> Version {
    match res.split(' ').collect::<Vec<&str>>().as_slice() {
        [_binary, version] => Version::parse(version).unwrap_or(DEFAULT_VERSION),
        _ => DEFAULT_VERSION,
    }
}

#[test]
fn test_parse_clap_version() -> Result<()> {
    let version_str = "fedimintd 0.3.0-alpha";
    let expected_version = Version::parse("0.3.0-alpha")?;
    assert_eq!(expected_version, parse_clap_version(version_str));

    let version_str = "fedimintd 0.3.12";
    let expected_version = Version::parse("0.3.12")?;
    assert_eq!(expected_version, parse_clap_version(version_str));

    let version_str = "fedimint-cli 2.12.2-rc22";
    let expected_version = Version::parse("2.12.2-rc22")?;
    assert_eq!(expected_version, parse_clap_version(version_str));

    let version_str = "bad version";
    let expected_version = DEFAULT_VERSION;
    assert_eq!(expected_version, parse_clap_version(version_str));

    Ok(())
}