add fastapi

basic_test.py

@@ -0,0 +1,18 @@
+import os
+from pytest import mark
+
+def test_one():
+    assert 2 + 2 == 4
+
+def test_nonstandard_module():
+    import numpy as np
+    assert np.linspace(1,2).shape == (50,)
+
+@mark.skipif(os.getenv('GITHUB_ACTIONS') != 'true',
+             reason = 'Not running on GHA')
+def test_version():
+    import sys
+    vi = sys.version_info
+    found = f'python{vi.major}{vi.minor}'
+    expected = os.getenv('EXPECTED_PY')
+    assert(found == expected)

flake.lock

@@ -0,0 +1,60 @@
+{
+  "nodes": {
+    "flake-compat": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1641205782,
+        "narHash": "sha256-4jY7RCWUoZ9cKD8co0/4tFARpWB+57+r1bLLvXNJliY=",
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "b7547d3eed6f32d06102ead8991ec52ab0a4f1a7",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1642700792,
+        "narHash": "sha256-XqHrk7hFb+zBvRg6Ghl+AZDq03ov6OshJLiSWOoX5es=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "846b2ae0fc4cc943637d3d1def4454213e203cba",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1655200170,
+        "narHash": "sha256-/yzkX+10sJhYNIcTtZ5ObS+nh/HrJp01XLaubzbRDcU=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "9ff91ce2e4c5d70551d4c8fd8830931c6c6b26b8",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-22.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-compat": "flake-compat",
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,86 @@
+# The core functionality is provided here using flakes. Legacy support for
+# `nix-shell` is provided by a wrapper in `shell.nix`.
+
+# TODO Hacking around the Qt problems
+# TODO PyPI package not in nixpkgs
+
+
+{
+  description = "Python development environment";
+
+  inputs = {
+
+    # Version pinning is managed in flake.lock. Upgrading can be done with
+    # something like
+    #
+    #    nix flake lock --update-input nixpkgs
+
+    nixpkgs     .url = "github:nixos/nixpkgs/nixos-22.05";
+    flake-utils .url = "github:numtide/flake-utils";
+    flake-compat = {
+      url = "github:edolstra/flake-compat";
+      flake = false;
+    };
+
+  };
+
+  outputs = { self, nixpkgs, flake-utils, ... }:
+
+    # Option 1: try to support each default system
+    flake-utils.lib.eachDefaultSystem # NB Some packages in nixpkgs are not supported on some systems
+
+      # Option 2: try to support selected systems
+      # flake-utils.lib.eachSystem ["x86_64-linux" "i686-linux" "aarch64-linux" "x86_64-darwin"]
+      (system:
+
+        let
+          pkgs = import nixpkgs {
+            inherit system;
+            # Any overlays you need can go here
+            overlays = [ ];
+          };
+
+          # ----- A Python interpreter with the packages that interest us -------
+          python-with-all-my-packages = (python:
+            (python.withPackages (ps: [
+              ps.pytest
+              ps.fastapi
+            ])));
+
+        in
+        rec {
+
+          #devShell = self.devShells.${ system }.python310; # does not need `rec`
+          devShell = devShells.python310;
+
+          devShells =
+            builtins.listToAttrs (
+              builtins.map
+                (
+                  pythonVersion: {
+                    name = pythonVersion;
+                    value = pkgs.mkShell {
+                      buildInputs = [
+                        (python-with-all-my-packages pkgs.${ pythonVersion })
+                        pkgs.just
+                        pkgs.cowsay
+                      ];
+                      packages = [
+                        pkgs.python3Packages.python-lsp-server
+                        pkgs.lolcat
+                        pkgs.exa
+                      ];
+                      shellHook =
+                        ''
+                          export PS1="${pythonVersion} devshell> "
+                          alias foo='cowsay Foo'
+                          alias bar='exa -l | lolcat'
+                          alias baz='cowsay What is the difference between buildIntputs and packages? | lolcat'
+                        '';
+                    };
+                  }
+                ) [ "python37" "python38" "python39" "python310" ]
+            );
+        }
+      );
+}

justfile

@@ -0,0 +1,4 @@
+# -*-Makefile-*-
+
+test colours='':
+     pytest -v {{colours}}

shell.nix

@@ -0,0 +1,15 @@
+# Adapts flake.nix to support legacy `nix-shell`
+
+(import
+  (
+    let
+      lock = builtins.fromJSON (builtins.readFile ./flake.lock);
+    in
+    fetchTarball {
+      url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+      sha256 = lock.nodes.flake-compat.locked.narHash;
+    }
+  )
+  {
+    src = ./.;
+  }).shellNix