Simplify how paths are pushed

Previously we were setting up Nix build hook to make sure all paths are
synced to cachix.

This had a few flaws:

- nix-daemon had to be restarted, resulting into a few seconds extra
  setup per each build
- spurious error on macos due to nix-daemon socket not ready in time
- significant overhead since syncing to cachix was synchronous for each
  derivation built

Now we just look for new store paths and push those after nix-build.

.github/workflows/test.yml

@@ -14,7 +14,7 @@ jobs:
     - run: yarn install --frozen-lockfile
     - run: yarn build
     - run: yarn test
-    - uses: cachix/install-nix-action@v6
+    - uses: cachix/install-nix-action@v7
     - name: Test public cache
       uses: ./
       with:

lib/main.js

@@ -18,25 +18,16 @@ var __importStar = (this && this.__importStar) || function (mod) {
 Object.defineProperty(exports, "__esModule", { value: true });
 const core = __importStar(require("@actions/core"));
 const exec = __importStar(require("@actions/exec"));
-const os_1 = require("os");
 const strings_1 = require("./strings");
-function home() {
-    if (os_1.type() == "Darwin") {
-        return "/Users/runner";
-    }
-    else {
-        return "/home/runner";
-    }
-}
 function run() {
     return __awaiter(this, void 0, void 0, function* () {
         try {
             // inputs
+            const name = core.getInput('name', { required: true });
             const file = core.getInput('file');
             const skipNixBuild = core.getInput('skipNixBuild');
             const attributes = core.getInput('attributes');
             const nixBuildArgs = core.getInput('nixBuildArgs');
-            const name = core.getInput('name', { required: true });
             const signingKey = core.getInput('signingKey');
             const authToken = core.getInput('authToken');
             const cachixExecutable = "/nix/var/nix/profiles/per-user/runner/profile/bin/cachix";
@@ -51,43 +42,27 @@ function run() {
             yield exec.exec('cachix', ['use', name]);
             core.endGroup();
             if (signingKey !== "") {
-                core.startGroup('Cachix: Configuring push');
-                // needed to discover auth token
-                yield exec.exec("sudo", ["sh", "-c", `echo export HOME=${home()} > /etc/nix/cachix-push.sh`]);
-                yield exec.exec("sudo", ["sh", "-c", `echo export CACHIX_SIGNING_KEY=${signingKey} >> /etc/nix/cachix-push.sh`]);
-                // needed to for nix-store
-                yield exec.exec("sudo", ["sh", "-c", `echo export PATH=\\$PATH:/nix/var/nix/profiles/default/bin:/nix/var/nix/profiles/per-user/runner/profile/bin >> /etc/nix/cachix-push.sh`]);
-                yield exec.exec("sudo", ["sh", "-c", `echo ${cachixExecutable} push ${name} \\$OUT_PATHS >> /etc/nix/cachix-push.sh`]);
-                yield exec.exec("sudo", ["sh", "-c", `chmod +x /etc/nix/cachix-push.sh`]);
-                // enable post-build-hook
-                yield exec.exec("sudo", ["sh", "-c", `echo post-build-hook = /etc/nix/cachix-push.sh >> /etc/nix/nix.conf`]);
                 core.exportVariable('CACHIX_SIGNING_KEY', signingKey);
-                // Ignore reloading failures as Nix might be installed in single-user mode (install-nix-action version 5 or lower)
+                if (skipNixBuild !== 'true') {
-                const options = { ignoreReturnCode: true };
+                    core.startGroup(`Invoking nix-build`);
-                // Reload nix-daemon
+                    // Remember existing store paths
-                if (os_1.type() == "Darwin") {
+                    yield exec.exec("sh", ["-c", `nix path-info --all | grep -v '\.drv$' > store-path-pre-build`]);
-                    // kickstart awaits nix-daemon to get up again
+                    let paths = '';
-                    yield exec.exec("sudo", ["launchctl", "kickstart", "-k", "system/org.nixos.nix-daemon"], options);
+                    const options = {
+                        listeners: {
+                            stdout: (data) => {
+                                paths += data.toString();
+                            },
+                        }
+                    };
+                    const args = strings_1.prependEach('-A', strings_1.nonEmptySplit(attributes, /\s+/)).concat([file || "default.nix"]);
+                    const additionalArgs = strings_1.nonEmptySplit(nixBuildArgs, /\s+/);
+                    yield exec.exec('nix-build', additionalArgs.concat(args), options);
+                    core.endGroup();
+                    core.startGroup('Cachix: Pushing paths');
+                    yield exec.exec("sh", ["-c", `nix path-info --all | grep -v '\.drv$' | cat - store-path-pre-build | sort | uniq -u  | ${cachixExecutable} push ${name}`]);
+                    core.endGroup();
                 }
-                else {
-                    yield exec.exec("sudo", ["pkill", "-HUP", "nix-daemon"], options);
-                }
-                core.endGroup();
-            }
-            if (skipNixBuild !== 'true') {
-                core.startGroup(`Invoking nix-build`);
-                let paths = '';
-                const options = {
-                    listeners: {
-                        stdout: (data) => {
-                            paths += data.toString();
-                        },
-                    }
-                };
-                const args = strings_1.prependEach('-A', strings_1.nonEmptySplit(attributes, /\s+/)).concat([file || "default.nix"]);
-                const additionalArgs = strings_1.nonEmptySplit(nixBuildArgs, /\s+/);
-                yield exec.exec('nix-build', additionalArgs.concat(args), options);
-                core.endGroup();
             }
         }
         catch (error) {

src/main.ts

@@ -1,24 +1,17 @@
 import * as core from '@actions/core';
 import * as exec from '@actions/exec';
-import { type } from 'os';
 import { prependEach, nonEmptySplit } from './strings';
+import { exit } from 'process';
 
-function home() {
-  if (type() == "Darwin") {
-    return "/Users/runner";
-  } else {
-    return "/home/runner";
-  }
-}
 
 async function run() {
   try {
     // inputs
+    const name = core.getInput('name', { required: true });
     const file = core.getInput('file');
     const skipNixBuild = core.getInput('skipNixBuild');
     const attributes = core.getInput('attributes');
     const nixBuildArgs = core.getInput('nixBuildArgs');
-    const name = core.getInput('name', { required: true });
     const signingKey = core.getInput('signingKey');
     const authToken = core.getInput('authToken')
     const cachixExecutable = "/nix/var/nix/profiles/per-user/runner/profile/bin/cachix";
@@ -37,44 +30,31 @@ async function run() {
     core.endGroup();
 
     if (signingKey !== "") {
-      core.startGroup('Cachix: Configuring push');
-      // needed to discover auth token
-      await exec.exec("sudo", ["sh", "-c", `echo export HOME=${home()} > /etc/nix/cachix-push.sh`]);
-      await exec.exec("sudo", ["sh", "-c", `echo export CACHIX_SIGNING_KEY=${signingKey} >> /etc/nix/cachix-push.sh`]);
-      // needed to for nix-store
-      await exec.exec("sudo", ["sh", "-c", `echo export PATH=\\$PATH:/nix/var/nix/profiles/default/bin:/nix/var/nix/profiles/per-user/runner/profile/bin >> /etc/nix/cachix-push.sh`]);
-      await exec.exec("sudo", ["sh", "-c", `echo ${cachixExecutable} push ${name} \\$OUT_PATHS >> /etc/nix/cachix-push.sh`]);
-      await exec.exec("sudo", ["sh", "-c", `chmod +x /etc/nix/cachix-push.sh`]);
-      // enable post-build-hook
-      await exec.exec("sudo", ["sh", "-c", `echo post-build-hook = /etc/nix/cachix-push.sh >> /etc/nix/nix.conf`]);
       core.exportVariable('CACHIX_SIGNING_KEY', signingKey);
+   
+      if (skipNixBuild !== 'true') {
+        core.startGroup(`Invoking nix-build`);
 
-      // Ignore reloading failures as Nix might be installed in single-user mode (install-nix-action version 5 or lower)
+        // Remember existing store paths
-      const options = { ignoreReturnCode: true };
+        await exec.exec("sh", ["-c", `nix path-info --all | grep -v '\.drv$' > store-path-pre-build`]);
-      // Reload nix-daemon
+
-      if (type() == "Darwin") {
+        let paths = '';
-        // kickstart awaits nix-daemon to get up again
+        const options = {
-        await exec.exec("sudo", ["launchctl", "kickstart", "-k", "system/org.nixos.nix-daemon"], options);
+          listeners: {
-      } else {
+            stdout: (data: Buffer) => {
-        await exec.exec("sudo", ["pkill", "-HUP", "nix-daemon"], options);
+              paths += data.toString();
+            },
+          }
+        };
+        const args = prependEach('-A', nonEmptySplit(attributes, /\s+/)).concat([file || "default.nix"]);
+        const additionalArgs = nonEmptySplit(nixBuildArgs, /\s+/);
+        await exec.exec('nix-build', additionalArgs.concat(args), options);
+        core.endGroup()
+
+        core.startGroup('Cachix: Pushing paths');
+        await exec.exec("sh", ["-c", `nix path-info --all | grep -v '\.drv$' | cat - store-path-pre-build | sort | uniq -u  | ${cachixExecutable} push ${name}`]);
+        core.endGroup();
       }
-
-      core.endGroup();
-    }
-    if (skipNixBuild !== 'true') {
-      core.startGroup(`Invoking nix-build`);
-      let paths = '';
-      const options = {
-        listeners: {
-          stdout: (data: Buffer) => {
-            paths += data.toString();
-          },
-        }
-      };
-      const args = prependEach('-A', nonEmptySplit(attributes, /\s+/)).concat([file || "default.nix"]);
-      const additionalArgs = nonEmptySplit(nixBuildArgs, /\s+/);
-      await exec.exec('nix-build', additionalArgs.concat(args), options);
-      core.endGroup()
     }
   } catch (error) {
     core.setFailed(`Action failed with error: ${error}`);