Give users chance to use their own rust version in nix-shell.

Example usage: nix-shell --arg norust true

Update mozilla-pkgs overlay in order to get the fix for
mozilla/nixpkgs-mozilla#225 and enable us
to update rust nightly to latest snapshot (done on behalf of this
commit too).

nix/README.md

@@ -33,5 +33,10 @@ With the overlay in place you can start nix-shell a within the project root.
 To have iscsid enabled on your NixOS system you can use the service file
 in your `configuration`.
 
+## nix-shell
 
+Build environment for mayastor including all test and debug dependencies.
+It can be run with two arguments:
 
+* `--arg nospdk true`: to use your own SPDK.
+* `--arg norust true`: to use your own rust toolchain.

nix/lib/rust.nix

@@ -3,6 +3,6 @@ let
   pkgs = import sources.nixpkgs { overlays = [ (import sources.nixpkgs-mozilla) ]; };
 in
 rec {
-  nightly = pkgs.rustChannelOf { channel = "nightly"; date = "2020-06-21"; };
+  nightly = pkgs.rustChannelOf { channel = "nightly"; date = "2020-07-26"; };
   stable = pkgs.rustChannelOf { channel = "stable"; };
 }

nix/pkgs/mayastor/default.nix

@@ -35,9 +35,8 @@ let
 in
 rustPlatform.buildRustPackage rec {
   name = "mayastor";
-  cargoSha256 = "10vq6856l8ggfhqp2yayby199vdrngkid3bsfsnrys0rvczr645m";
-
   #cargoSha256 = "0000000000000000000000000000000000000000000000000000";
+  cargoSha256 = "10vq6856l8ggfhqp2yayby199vdrngkid3bsfsnrys0rvczr645m";
   version = sources.mayastor.branch;
   src = if release then sources.mayastor else
   whitelistSource ../../../. [

nix/sources.json

@@ -63,13 +63,13 @@
     "nixpkgs-mozilla": {
         "branch": "master",
         "description": "mozilla related nixpkgs (extends nixos/nixpkgs repo)",
-        "homepage": null,
+        "homepage": "https://github.com/mozilla/nixpkgs-mozilla",
         "owner": "mozilla",
         "repo": "nixpkgs-mozilla",
-        "rev": "e912ed483e980dfb4666ae0ed17845c4220e5e7c",
-        "sha256": "08fvzb8w80bkkabc1iyhzd15f4sm7ra10jn32kfch5klgl0gj3j3",
+        "rev": "efda5b357451dbb0431f983cca679ae3cd9b9829",
+        "sha256": "11wqrg86g3qva67vnk81ynvqyfj0zxk83cbrf0p9hsvxiwxs8469",
         "type": "tarball",
-        "url": "https://github.com/mozilla/nixpkgs-mozilla/archive/e912ed483e980dfb4666ae0ed17845c4220e5e7c.tar.gz",
+        "url": "https://github.com/mozilla/nixpkgs-mozilla/archive/efda5b357451dbb0431f983cca679ae3cd9b9829.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     }
 }

shell.nix

@@ -1,4 +1,6 @@
-{ nospdk ? false }:
+{ nospdk ? false
+, norust ? false
+}:
 let
   sources = import ./nix/sources.nix;
   pkgs = import sources.nixpkgs {
@@ -10,15 +12,15 @@ let
 in
 with pkgs;
 let
-  moth = "You have requested environment without SPDK, you should provide it!";
+  nospdk_moth = "You have requested environment without SPDK, you should provide it!";
+  norust_moth = "You have requested environment without rust, you should provide it!";
   channel = import ./nix/lib/rust.nix { inherit sources; };
 in
 mkShell {
 
   # fortify does not work with -O0 which is used by spdk when --enable-debug
   hardeningDisable = [ "fortify" ];
   buildInputs = [
-    channel.nightly.rust
     clang
     cowsay
     e2fsprogs
@@ -41,18 +43,24 @@ mkShell {
     python3
     utillinux
     xfsprogs
-  ] ++ pkgs.lib.optionals (nospdk) libspdk.buildInputs
-  ++ pkgs.lib.optional (!nospdk) libspdk;
+  ]
+  ++ (if (nospdk) then [ libspdk.buildInputs ] else [ libspdk ])
+  ++ pkgs.lib.optional (!norust) channel.nightly.rust;
+
   LIBCLANG_PATH = mayastor.LIBCLANG_PATH;
   PROTOC = mayastor.PROTOC;
   PROTOC_INCLUDE = mayastor.PROTOC_INCLUDE;
-
   SPDK_PATH = if nospdk then null else "${libspdk}";
+
   shellHook = ''
-    ${pkgs.lib.optionalString (nospdk) "cowsay ${moth}"}
+    ${pkgs.lib.optionalString (nospdk) "cowsay ${nospdk_moth}"}
     ${pkgs.lib.optionalString (nospdk) "export CFLAGS=-msse4"}
     ${pkgs.lib.optionalString (nospdk)
       ''export RUSTFLAGS="-C link-args=-Wl,-rpath,$(pwd)/spdk-sys/spdk"''}
+    ${pkgs.lib.optionalString (nospdk) "echo"}
+    ${pkgs.lib.optionalString (norust) "cowsay ${norust_moth}"}
+    ${pkgs.lib.optionalString (norust) "echo 'Hint: use rustup tool.'"}
+    ${pkgs.lib.optionalString (norust) "echo"}
     pre-commit install
   '';
 }