Replace port-check with custom async free_local_port function

Now that the `new` function is async, we should not use blocking
calls to std. Since we will eventually transition to async-std
anyway, we can start depending on it here.

Author: thomaseizinger

Cargo.lock

@@ -6,6 +6,7 @@ edition = "2018"
 
 [dependencies]
 anyhow = "1.0.25"
+async-std = "1.2.0"
 derive_more = "0.99.2"
 dirs = "2"
 emerald-vault-core = { git = "http://github.com/thomaseizinger/emerald-vault.git", branch = "create-comit-app-compatible", default-features = false }
@@ -17,7 +18,6 @@ hex = "0.4.0"
 hex-literal = "0.2.1"
 hex-serde = "0.1.0"
 lazy_static = "1.4"
-port_check = "0.1"
 reqwest = { version = "0.9", default-features = false }
 rust_bitcoin = { version = "0.19.1", package = "bitcoin" }
 secp256k1 = { version = "0.12", features = ["rand"] }

Cargo.toml

@@ -1,4 +1,6 @@
-use crate::docker::{self, DockerImage, LogMessage, DOCKER_NETWORK};
+use crate::docker::{
+    self, free_local_port::free_local_port, DockerImage, LogMessage, DOCKER_NETWORK,
+};
 use anyhow::Context;
 use futures::compat::Future01CompatExt;
 use reqwest::r#async::Client;
@@ -56,14 +58,12 @@ pub async fn new_bitcoind_instance() -> anyhow::Result<BitcoindInstance> {
         "-txindex",
     ]);
 
-    let p2p_port =
-        port_check::free_local_port().ok_or(anyhow::anyhow!("failed to grab a free local port"))?;
+    let p2p_port = free_local_port().await?;
     options_builder.expose(18444, "tcp", p2p_port as u32);
 
     let p2p_uri = BitcoindP2PUri { port: p2p_port };
 
-    let http_port =
-        port_check::free_local_port().ok_or(anyhow::anyhow!("failed to grab a free local port"))?;
+    let http_port = free_local_port().await?;
     options_builder.expose(18443, "tcp", http_port as u32);
 
     let http_endpoint = BitcoindHttpEndpoint { port: http_port };

src/docker/bitcoin.rs

@@ -1,5 +1,5 @@
 use crate::{
-    docker::{self, DockerImage, LogMessage, DOCKER_NETWORK},
+    docker::{self, free_local_port::free_local_port, DockerImage, LogMessage, DOCKER_NETWORK},
     temp_fs,
 };
 use futures::compat::Future01CompatExt;
@@ -44,8 +44,7 @@ pub async fn new_instance(index: u32) -> anyhow::Result<CndInstance> {
     options_builder.cmd(vec!["--", "cnd", "--config=/config/cnd.toml"]);
     options_builder.volumes(vec![&format!("{}:/config", config_folder.display())]);
 
-    let http_port =
-        port_check::free_local_port().ok_or(anyhow::anyhow!("failed to grab a free local port"))?;
+    let http_port = free_local_port().await?;
     options_builder.expose(8080, "tcp", http_port as u32);
 
     let options = options_builder.build();

src/docker/cnd.rs

@@ -1,4 +1,6 @@
-use crate::docker::{self, DockerImage, LogMessage, DOCKER_NETWORK};
+use crate::docker::{
+    self, free_local_port::free_local_port, DockerImage, LogMessage, DOCKER_NETWORK,
+};
 use emerald_rs::PrivateKey;
 use futures::compat::Future01CompatExt;
 use lazy_static::lazy_static;
@@ -44,8 +46,7 @@ pub async fn new_parity_instance() -> anyhow::Result<ParityInstance> {
     options_builder.name("ethereum");
     options_builder.network_mode(DOCKER_NETWORK);
 
-    let http_port =
-        port_check::free_local_port().ok_or(anyhow::anyhow!("failed to grab a free local port"))?;
+    let http_port = free_local_port().await?;
     options_builder.expose(8545, "tcp", http_port as u32);
 
     let http_endpoint = ParityHttpEndpoint { port: http_port };

src/docker/ethereum.rs

@@ -0,0 +1,13 @@
+use anyhow::Context;
+use async_std::net::TcpListener;
+use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4};
+
+pub async fn free_local_port() -> anyhow::Result<u16> {
+    let socket = SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::LOCALHOST, 0));
+    let listener = TcpListener::bind(&socket)
+        .await
+        .with_context(|| format!("unable to bind to {}", socket))?;
+    let socket_addr = listener.local_addr()?;
+
+    Ok(socket_addr.port())
+}

src/docker/free_local_port.rs

@@ -8,6 +8,7 @@ use tokio::prelude::{stream::Stream, Future};
 pub mod bitcoin;
 pub mod cnd;
 pub mod ethereum;
+mod free_local_port;
 
 pub const DOCKER_NETWORK: &str = "create-comit-app";