use fenix to build package, have runner script; nix run works now!

.cargo/config.toml

@@ -1,5 +1,6 @@
 [target.riscv32imac-unknown-none-elf]
-runner = "sudo espflash flash --monitor --chip esp32c6"
+# UPDATE flake.nix to reflect any changes here in the wrapper script
+runner = "espflash flash --monitor --chip esp32c6"
 
 [env]
 ESP_LOG="info"

flake.lock

@@ -1,5 +1,69 @@
 {
   "nodes": {
+    "fenix": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "rust-analyzer-src": "rust-analyzer-src"
+      },
+      "locked": {
+        "lastModified": 1775462255,
+        "narHash": "sha256-YRzdvh6nvMebcgO2nDpr8dqVwKHpp1BBRUHeMxX9UAY=",
+        "owner": "nix-community",
+        "repo": "fenix",
+        "rev": "f90343f1ed330243d4bbdbce51acbd93b776a797",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "fenix",
+        "type": "github"
+      }
+    },
+    "fenix_2": {
+      "inputs": {
+        "nixpkgs": [
+          "naersk",
+          "nixpkgs"
+        ],
+        "rust-analyzer-src": "rust-analyzer-src_2"
+      },
+      "locked": {
+        "lastModified": 1752475459,
+        "narHash": "sha256-z6QEu4ZFuHiqdOPbYss4/Q8B0BFhacR8ts6jO/F/aOU=",
+        "owner": "nix-community",
+        "repo": "fenix",
+        "rev": "bf0d6f70f4c9a9cf8845f992105652173f4b617f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "fenix",
+        "type": "github"
+      }
+    },
+    "naersk": {
+      "inputs": {
+        "fenix": "fenix_2",
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1769799857,
+        "narHash": "sha256-88IFXZ7Sa1vxbz5pty0Io5qEaMQMMUPMonLa3Ls/ss4=",
+        "owner": "nix-community",
+        "repo": "naersk",
+        "rev": "9d4ed44d8b8cecdceb1d6fd76e74123d90ae6339",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "naersk",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1775403759,
@@ -18,27 +82,42 @@
     },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs",
+        "fenix": "fenix",
-        "rust-overlay": "rust-overlay"
+        "naersk": "naersk",
+        "nixpkgs": "nixpkgs"
       }
     },
-    "rust-overlay": {
+    "rust-analyzer-src": {
-      "inputs": {
+      "flake": false,
-        "nixpkgs": [
-          "nixpkgs"
-        ]
-      },
       "locked": {
-        "lastModified": 1775445266,
+        "lastModified": 1775429583,
-        "narHash": "sha256-3fgIj85WHQbOamrpIw9WY3ZL1PoEvjPOjmzMYNsEQJo=",
+        "narHash": "sha256-bFC/p7Ywyd9QIr9DbU3Q75c7AcaCm9wVmEvcI3702cY=",
-        "owner": "oxalica",
+        "owner": "rust-lang",
-        "repo": "rust-overlay",
+        "repo": "rust-analyzer",
-        "rev": "61747bc3cf2da179b9af356ae9e70f3b895b0c24",
+        "rev": "38fb8f92ac15853d7fa9fb47fc2d81fdd5cd6c7e",
         "type": "github"
       },
       "original": {
-        "owner": "oxalica",
+        "owner": "rust-lang",
-        "repo": "rust-overlay",
+        "ref": "nightly",
+        "repo": "rust-analyzer",
+        "type": "github"
+      }
+    },
+    "rust-analyzer-src_2": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1752428706,
+        "narHash": "sha256-EJcdxw3aXfP8Ex1Nm3s0awyH9egQvB2Gu+QEnJn2Sfg=",
+        "owner": "rust-lang",
+        "repo": "rust-analyzer",
+        "rev": "591e3b7624be97e4443ea7b5542c191311aa141d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "rust-lang",
+        "ref": "nightly",
+        "repo": "rust-analyzer",
         "type": "github"
       }
     }

flake.nix

@@ -1,32 +1,53 @@
 {
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
-    rust-overlay = {
+    fenix = {
       inputs.nixpkgs.follows = "nixpkgs";
-      url = "github:oxalica/rust-overlay";
+      url = "github:nix-community/fenix";
+    };
+    naersk = {
+      inputs.nixpkgs.follows = "nixpkgs";
+      url = "github:nix-community/naersk";
     };
   };
   outputs = {
+    fenix,
+    naersk,
     nixpkgs,
-    rust-overlay,
     ...
   }: let
-    pkgs = import nixpkgs {
+    pkgs = nixpkgs.legacyPackages.x86_64-linux;
-      system = "x86_64-linux";
+    toolchain = fenix.packages.x86_64-linux.fromToolchainFile {
-      overlays = [(import rust-overlay)];
+      file = ./rust-toolchain.toml;
+      sha256 = "sha256-zC8E38iDVJ1oPIzCqTk/Ujo9+9kx9dXq7wAwPMpkpg0=";
     };
-    rust-bin = pkgs.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml;
   in {
     devShells.x86_64-linux.default = pkgs.mkShell {
       buildInputs = [
         pkgs.espflash
         pkgs.esp-generate
         pkgs.rust-analyzer
-        rust-bin
+        toolchain
       ];
       shellHook = ''
-        export RUSTUP_TOOLCHAIN=${rust-bin}
+        export RUSTUP_TOOLCHAIN=${toolchain}
       '';
     };
+    packages.x86_64-linux.default =
+      (naersk.lib.x86_64-linux.override {
+        cargo = toolchain;
+        rustc = toolchain;
+      }).buildPackage {
+        src = ./.;
+        # UPDATE .cargo/config.toml to reflect changes here in the runner
+        postInstall = ''
+          mv $out/bin/esp32c6-play $out/bin/.esp32c6-play
+          cat<<EOF>$out/bin/esp32c6-play
+          #!/usr/bin/bash
+          ${pkgs.lib.getExe pkgs.espflash} flash --monitor --chip esp32c6 $(echo $out)/bin/.esp32c6-play
+          EOF
+          chmod +x $out/bin/esp32c6-play
+        '';
+      };
   };
 }

src/main.rs

@@ -16,9 +16,9 @@ esp_bootloader_esp_idf::esp_app_desc!();
 fn main() -> ! {
     let peripherals = init();
 
-    let mut led_buffer = smart_led_buffer!(1);
+    let mut led_buffer = smart_led_buffer!(1 /* # of leds */);
     let mut rgb_led = {
-        let frequency = Rate::from_mhz(80);
+        let frequency = Rate::from_mhz(80); // max frequency of RMT
         let rmt = Rmt::new(peripherals.RMT, frequency).expect("failed to initialize RMT0");
         SmartLedsAdapter::new(rmt.channel0, peripherals.GPIO8, &mut led_buffer)
     };
@@ -28,6 +28,7 @@ fn main() -> ! {
             let r: u8 = i;
             let g: u8 = i + 255 / 3; // phase shifted a third
             let b: u8 = i + 2 * (255 / 3); // phase shifted two thirds
+
             write_rgb(&mut rgb_led, RGB::new(sin(r), sin(g), sin(b)));
 
             wait_ms(8);