Cleanup and document nix usage

.dockerignore

@@ -1 +1,3 @@
 .venv
+result
+*.Dockerfile

.github/workflows/nix-auto.yml

@@ -1,4 +1,4 @@
-name: Nix Flake actions
+name: CI tasks from Nix config
 
 on:
   pull_request:

README.md

@@ -17,6 +17,11 @@ See the [Development](#development) section for how to get the test agent runnin
 
 ## Installation
 
+The test agent can be installed using nix:
+
+    nix profile install github:datadog/dd-apm-test-agent#ddapm-test-agent
+    # nix profile upgrade ddapm-test-agent # to upgrade
+
 The test agent can be installed from PyPI:
 
     pip install ddapm-test-agent

build-on-darwin.Dockerfile

@@ -0,0 +1,28 @@
+# simple hack to build the same image on OSX. otherwise the Nix docker build will by default not cross compile to linux
+# in CI or on linux systems - use `nix build .#image | docker load -i result` instead
+
+FROM nixos/nix AS builder
+RUN   set -xe; \
+    echo 'sandbox = true' >> /etc/nix/nix.conf; \
+    echo 'filter-syscalls = false' >> /etc/nix/nix.conf; \
+    echo 'max-jobs = auto' >> /etc/nix/nix.conf; \
+    echo 'experimental-features = nix-command flakes' >> /etc/nix/nix.conf
+
+WORKDIR /build
+COPY flake.lock *.nix .
+
+RUN nix flake show
+
+
+COPY . .
+
+RUN nix build .#image
+RUN mkdir -p /output; mkdir -p /img
+# very simplistic way to unpack image - relies only on there being a single layer
+RUN tar -xf result --strip-components=1 -C /img 
+RUN tar -xf /img/layer.tar -C /output
+
+FROM scratch AS final
+COPY --from=builder /output/ /
+
+ENTRYPOINT ["/bin/ddapm-test-agent"]

flake.nix

@@ -7,7 +7,6 @@
 
     flake-utils.url = "github:numtide/flake-utils";
 
-    nix2containerPkg.url = "github:nlewo/nix2container";
     treefmt-nix.url = "github:numtide/treefmt-nix";
 
     nix-github-actions.url = "github:nix-community/nix-github-actions/";
@@ -20,7 +19,6 @@
       nixpkgs,
       flake-utils,
       treefmt-nix,
-      nix2containerPkg,
       nix-github-actions,
     }:
     (flake-utils.lib.eachDefaultSystem (
@@ -32,8 +30,6 @@
 
         treefmt = treefmt-nix.lib.evalModule pkgs ./treefmt.nix;
 
-        nix2container = nix2containerPkg.packages.${system}.nix2container;
-
         # include dependencies not publish to nixpkgs
         ddsketch = pkgs.callPackage ./ddsketch.nix { inherit python pkgs; };
         ddtrace = pkgs.callPackage ./ddtrace.nix { inherit python pkgs ddsketch; };
@@ -94,31 +90,19 @@
         );
 
         ddapm-test-agent = ddapm-test-agent_base { doCheck = false; };
+        skopeo = pkgs.skopeo;
 
-        run_with_agent = pkgs.writeShellScriptBin "run_with_agent" ''
-          #!${pkgs.bash}/bin/bash
-          set -euxo pipefail
-
-          ${pkgs.coreutils}/bin/nohup ${pkgs.bash}/bin/bash -c "${ddapm-test-agent}/bin/ddapm-test-agent" &
-
-          exec $@
-        '';
-
-        toolContainer = nix2container.buildImage {
+        image = pkgs.dockerTools.buildImage {
           name = "ghcr.io/pawelchcki/ddapm-test-agent";
           tag = "latest";
-          config = {
-            entrypoint = [ "/bin/ddapm-test-agent" ];
-          };
-
           copyToRoot = pkgs.buildEnv {
             name = "root";
-            paths = [
-              ddapm-test-agent
-              run_with_agent
-            ];
+            paths = [ ddapm-test-agent ];
             pathsToLink = [ "/bin" ];
           };
+          config = {
+            entrypoint = [ "/bin/ddapm-test-agent" ];
+          };
         };
       in
       {
@@ -128,8 +112,8 @@
             ddapm-test-agent
             ddtrace
             ddsketch
-            toolContainer
-            run_with_agent
+            image
+            skopeo
             ;
           default = ddapm-test-agent;
           reno = pkgs.reno;
@@ -144,10 +128,7 @@
 
         devShells.default = pkgs.mkShell {
           venvDir = "./.venv";
-          nativeBuildInputs = ddapm-test-agent.nativeBuildInputs ++ [
-            ddapm-test-agent
-            run_with_agent
-          ];
+          nativeBuildInputs = ddapm-test-agent.nativeBuildInputs ++ [ ddapm-test-agent ];
         };
       }
     ))