feat(*): init Rust port

This is a Rust port of the original Perl script, legacy cruft is removed
and it focuses on a modern Hydra deployment.

Nonetheless, it knows how to perform migrations based on the channel
versions.

Signed-off-by: Raito Bezarius <masterancpp@gmail.com>

.gitignore

@@ -1 +1,6 @@
 result
+
+
+# Added by cargo
+
+/target

Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "nixos-channel-scripts"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+clap = { version = "4.5.13", features = [ "derive" ] }
+object_store = { version = "0.10.2", features = [ "aws" ] }

src/actions.rs

@@ -0,0 +1,27 @@
+use std::path::PathBuf;
+
+enum HydraProductType {
+    BrotliJson,
+    SourceDistribution,
+}
+
+impl ToString for HydraProductType {
+    fn to_string(&self) -> String {
+        match self {
+            Self::BrotliJson => "json-br".to_string(),
+            Self::SourceDistribution => "source-dist".to_string(),
+        }
+    }
+}
+
+enum Action {
+    WriteFile {
+        dst_path: PathBuf,
+        contents: String
+    },
+    WriteHydraProduct {
+        dst_path: PathBuf,
+        product_name: String,
+        product_type: Option<HydraProductType>,
+    }
+}

src/config.rs

@@ -0,0 +1,12 @@
+use std::path::PathBuf;
+
+struct MirrorConfig {
+    /// URI to Hydra instance
+    hydra_uri: String,
+    /// URI to the binary cache
+    binary_cache_uri: String,
+    /// A path to a checkout of nixpkgs
+    nixpkgs_dir: PathBuf,
+    /// S3 releases bucket URL
+    s3_release_bucket_uri: String,
+}

src/main.rs

@@ -0,0 +1,30 @@
+mod config;
+mod actions;
+
+use std::path::PathBuf;
+
+use clap::Parser;
+
+#[derive(Parser, Debug)]
+#[command(version, about, long_about = None)]
+struct Args {
+    /// Channel name to update
+    channel_name: String,
+    /// Job name to fetch from Hydra instance
+    job_name: String,
+    /// TOML configuration file for channel updates
+    #[arg(short, long)]
+    config_file: PathBuf,
+    /// Whether to execute no remote side effects (S3 uploads, redirections), etc.
+    #[arg(short, long, default_value_t = false)]
+    dry_run: bool,
+    /// If a channel rollback is detected, do not bail out and proceed to rollback the channel
+    #[arg(short, long, default_value_t = false)]
+    ignore_rollback_protection: bool
+}
+
+fn main() {
+    let args = Args::parse();
+
+    println!("Hello, world!");
+}