Add Shell::Command abstraction to Gitlab::Backup::Cli

The new class will be responsible for all shell/commands execution

gems/gitlab-backup-cli/lib/gitlab/backup/cli.rb

@@ -8,6 +8,7 @@ module Cli
       autoload :Runner, 'gitlab/backup/cli/runner'
       autoload :Utils, 'gitlab/backup/cli/utils'
       autoload :Dependencies, 'gitlab/backup/cli/dependencies'
+      autoload :Shell, 'gitlab/backup/cli/shell'
 
       Error = Class.new(StandardError)
       # Your code goes here...

gems/gitlab-backup-cli/lib/gitlab/backup/cli/shell.rb

+# frozen_string_literal: true
+
+require 'open3'
+
+module Gitlab
+  module Backup
+    module Cli
+      module Shell
+        autoload :Command, 'gitlab/backup/cli/shell/command'
+      end
+    end
+  end
+end

gems/gitlab-backup-cli/lib/gitlab/backup/cli/shell/command.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Backup
+    module Cli
+      module Shell
+        # Abstraction to control shell command execution
+        # It provides an easier API to common usages
+        class Command
+          attr_reader :cmd_args, :env
+
+          # Result data structure from running a command
+          #
+          # @attr [String] stdout
+          # @attr [String] stderr
+          # @attr [Process::Status] status
+          # @attr [Float] duration
+          Result = Struct.new(:stdout, :stderr, :status, :duration, keyword_init: true)
+
+          # @example Usage
+          #   Shell.new('echo', 'Some amazing output').capture
+          # @param [Array<String>] cmd_args
+          # @param [Hash<String,String>] env
+          def initialize(*cmd_args, env: {})
+            @cmd_args = cmd_args
+            @env = env
+          end
+
+          # Execute a process and return its output and status
+          #
+          # @return [Command::Result] Captured output from executing a process
+          def capture
+            start = Time.now
+            stdout, stderr, status = Open3.capture3(env, *cmd_args)
+            duration = Time.now - start
+
+            Result.new(stdout: stdout, stderr: stderr, status: status, duration: duration)
+          end
+        end
+      end
+    end
+  end
+end

gems/gitlab-backup-cli/spec/gitlab/backup/cli/shell/command_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Backup::Cli::Shell::Command do
+  let(:envdata) do
+    { 'CUSTOM' => 'data' }
+  end
+
+  subject(:command) { described_class }
+
+  describe '#initialize' do
+    it 'accepts required attributes' do
+      expect { command.new('ls', '-l') }.not_to raise_exception
+    end
+
+    it 'accepts optional attributes' do
+      expect { command.new('ls', '-l', env: envdata) }.not_to raise_exception
+    end
+  end
+
+  describe '#capture' do
+    it 'returns stdout from executed command' do
+      expected_output = 'my custom content'
+
+      result = command.new('echo', expected_output).capture
+
+      expect(result.stdout.chomp).to eq(expected_output)
+      expect(result.stderr).to be_empty
+    end
+
+    it 'returns stderr from executed command' do
+      expected_output = 'my custom error content'
+
+      result = command.new('sh', '-c', "echo #{expected_output} > /dev/stderr").capture
+
+      expect(result.stdout).to be_empty
+      expect(result.stderr.chomp).to eq(expected_output)
+    end
+
+    it 'returns a Process::Status from the executed command' do
+      result = command.new('pwd').capture
+
+      expect(result.status).to be_a(Process::Status)
+      expect(result.status).to respond_to(:exited?, :termsig, :stopsig, :exitstatus, :success?, :pid)
+    end
+
+    it 'returns the execution duration' do
+      result = command.new('sleep 0.1').capture
+
+      expect(result.duration).to be > 0.1
+    end
+  end
+end