Init

flake.lock

+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1737885589,
+        "narHash": "sha256-Zf0hSrtzaM1DEz8//+Xs51k/wdSajticVrATqDrfQjg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "852ff1d9e153d8875a83602e03fdef8a63f0ecf8",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "pyproject-nix": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1737933698,
+        "narHash": "sha256-MpPHyTCrI7dpiRgzZTH7PEMLZCvI2Dc3iOr4GSaQ/II=",
+        "owner": "pyproject-nix",
+        "repo": "pyproject.nix",
+        "rev": "78ea10a115be7b7ae45b241d06392e014988a162",
+        "type": "github"
+      },
+      "original": {
+        "owner": "pyproject-nix",
+        "repo": "pyproject.nix",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs",
+        "pyproject-nix": "pyproject-nix"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

+{
+  description = "A basic flake using pyproject.toml project metadata";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    pyproject-nix = {
+      url = "github:pyproject-nix/pyproject.nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs =
+    { nixpkgs, flake-utils, pyproject-nix, ... }:
+
+    flake-utils.lib.eachDefaultSystem (
+      system: let
+        pkgs = nixpkgs.legacyPackages.${system};
+        # project = pyproject-nix.lib.project.loadRequirementsTxt { projectRoot = ./.; };
+        # pythonEnv = pkgs.python3.withPackages (project.renderers.withPackages { inherit python; });
+        propagatedBuildInputs = with pkgs; [
+            python312Packages.networkx
+            python312Packages.matplotlib
+            python312Packages.pygraphviz
+            graphviz
+        ];
+      in
+        {
+          devShells.default = pkgs.mkShell { packages = [ propagatedBuildInputs ]; };
+
+          packages = rec {
+            default = runscript;
+            runscript = pkgs.writers.writePython3Bin "run-script" {
+              libraries = propagatedBuildInputs;
+            } ./main.py;
+
+            # ./main.py;
+            docker = pkgs.dockerTools.buildImage {
+              name = "nxenv";
+              config = {
+                Cmd = [ "${runscript}" ];
+              };
+            };
+            apptainer = pkgs.singularity-tools.buildImage {
+              name = "nxenv";
+              runScript = "${runscript}";
+            };
+          };
+        });
+}

main.py

+import networkx as nx
+import matplotlib.pyplot as plt
+
+G = nx.watts_strogatz_graph(40, 3, 0.7, seed=12)
+pos = nx.nx_agraph.graphviz_layout(G, prog="fdp")
+fig = plt.figure()
+nx.draw(G, pos, ax=fig.add_subplot())
+fig.savefig("graph.png")