Add unix example

.gitignore

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+/target/

.idea/.gitignore

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+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml

.idea/command_gateway.iml

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+<?xml version="1.0" encoding="UTF-8"?>
+<module type="CPP_MODULE" version="4">
+  <component name="NewModuleRootManager">
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/target" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

.idea/modules.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/command_gateway.iml" filepath="$PROJECT_DIR$/.idea/command_gateway.iml" />
+    </modules>
+  </component>
+</project>

.idea/vcs.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>

Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "anyhow"
+version = "1.0.68"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2cb2f989d18dd141ab8ae82f64d1a8cdd37e0840f73a406896cf5e99502fab61"
+
+[[package]]
+name = "command_gateway"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+]

Cargo.toml

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+[package]
+name = "command_gateway"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[[bin]]
+name = "daemon"
+path = "src/daemon/bin/main.rs"
+
+[[bin]]
+name = "client"
+path = "src/client/bin/main.rs"
+
+[dependencies]
+anyhow = "^1.0.42"

src/client/bin/main.rs

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+use std::os::unix::net::{UnixListener, UnixStream};
+use std::io::{Read, Write};
+
+use anyhow::Context;
+
+fn main() -> anyhow::Result<()> {
+    let socket_path = "mysocket";
+
+    let mut unix_stream =
+        UnixStream::connect(socket_path).context("Could not create stream")?;
+
+    unix_stream
+        .write(b"Hello?")       // we write bytes, &[u8]
+        .context("Failed at writing onto the unix stream")?;
+
+    Ok(())
+}
+
+fn handle_stream(mut stream: UnixStream) -> anyhow::Result<()> {
+    // to be filled
+    Ok(())
+}

src/daemon/bin/main.rs

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+use std::os::unix::net::{UnixListener, UnixStream};
+use anyhow::Context;
+use std::io::{Read, Write};
+
+fn main() -> anyhow::Result<()> {
+    let socket_path = "mysocket";
+
+    if std::fs::metadata(socket_path).is_ok() {
+        println!("A socket is already present. Deleting...");
+        std::fs::remove_file(socket_path).with_context(|| {
+            format!("could not delete previous socket at {:?}", socket_path)
+        })?;
+    }
+
+    let unix_listener =
+        UnixListener::bind(socket_path).context("Could not create the unix socket")?;
+
+    // put the daemon logic in a loop to accept several connections
+    loop {
+        let (mut unix_stream, socket_address) = unix_listener
+            .accept()
+            .context("Failed at accepting a connection on the unix listener")?;
+        handle_stream(unix_stream)?;
+    }
+    Ok(())
+}
+
+fn handle_stream(mut unix_stream: UnixStream) -> anyhow::Result<()> {
+    let mut message = String::new();
+    unix_stream
+        .read_to_string(&mut message)
+        .context("Failed at reading the unix stream")?;
+
+    println!("{}", message);
+    Ok(())
+}