ci: move it to a container

Add nix flake and use it in the pipeline for reliability and reproducability.

Referenced issue:
* status-im/infra-ci#188

Author: markoburcul

README.md

@@ -23,6 +23,15 @@ npm install
 npm run doc
 ```
 
+# Using Nix shell
+```shell
+git clone https://github.com/waku-org/js-waku.git
+cd js-waku
+nix develop
+npm install
+npm run doc
+```
+
 ## Bugs, Questions & Features
 
 If you encounter any bug or would like to propose new features, feel free to [open an issue](https://github.com/waku-org/js-waku/issues/new/).

ci/Jenkinsfile

@@ -1,5 +1,13 @@
 pipeline {
-  agent { label 'linux' }
+  agent {
+    docker {
+      label 'linuxcontainer'
+      image 'harbor.status.im/infra/ci-build-containers:linux-base-1.0.0'
+      args '--volume=/nix:/nix ' +
+           '--volume=/etc/nix:/etc/nix ' +
+           '--user jenkins'
+    }
+  }
 
   options {
     disableConcurrentBuilds()
@@ -21,27 +29,35 @@ pipeline {
   stages {
     stage('Deps') {
       steps {
-        sh 'npm install'
+        script {
+          nix.develop('npm install', pure: true)
+        }
       }
     }
 
     stage('Packages') {
       steps {
-        sh 'npm run build'
+        script {
+          nix.develop('npm run build', pure: true)
+        }
       }
     }
 
     stage('Build') {
       steps {
-        sh 'npm run doc'
+        script {
+          nix.develop('npm run doc', pure: true)
+        }
       }
     }
 
     stage('Publish') {
       when { expression { GIT_BRANCH.endsWith('master') } }
       steps {
         sshagent(credentials: ['status-im-auto-ssh']) {
-          sh 'npm run deploy'
+          script {
+            nix.develop('npm run deploy', pure: true)
+          }
         }
       }
     }

flake.lock

@@ -0,0 +1,33 @@
+{
+  description = "Nix flake development shell.";
+
+  inputs = {
+    nixpkgs.url = "nixpkgs/nixos-25.05";
+  };
+
+  outputs =
+    { self, nixpkgs }:
+    let
+      supportedSystems = [
+        "x86_64-linux"
+        "aarch64-linux"
+        "x86_64-darwin"
+        "aarch64-darwin"
+      ];
+      forEachSystem = nixpkgs.lib.genAttrs supportedSystems;
+      pkgsFor = forEachSystem (system: import nixpkgs { inherit system; });
+    in
+    rec {
+      formatter = forEachSystem (system: pkgsFor.${system}.nixpkgs-fmt);
+
+      devShells = forEachSystem (system: {
+        default = pkgsFor.${system}.mkShellNoCC {
+          packages = with pkgsFor.${system}.buildPackages; [
+            git        # 2.44.1
+            openssh    # 9.7p1
+            nodejs_20  # v20.15.1
+          ];
+        };
+      });
+    };
+}