alloy.rb

class Alloy < Formula
    desc "Vendor-agnostic OpenTelemetry Collector distribution with programmable pipelines"
    homepage "https://grafana.com/docs/alloy/latest"
    url "https://github.com/grafana/alloy/archive/refs/tags/v1.3.1.tar.gz"
    sha256 "a33f1440fd18639d19fe3d3dfa2b404ebd663656b8f9929fd60e8945b6ee0632"
    license "Apache-2.0"
  
    depends_on "go@1.22" => :build
    depends_on "node" => :build
    depends_on "yarn" => :build

    on_linux do
      depends_on "systemd" => :build
    end

    def install
      ldflags = %W[
        -s -w
        -X github.com/grafana/alloy/internal/build.Branch=HEAD
        -X github.com/grafana/alloy/internal/build.Version=v#{version}
        -X github.com/grafana/alloy/internal/build.BuildUser=#{tap.user}
        -X github.com/grafana/alloy/internal/build.BuildDate=#{time.iso8601}
      ]
      args = std_go_args(ldflags: ldflags) + %w[-tags=builtinassets,noebpf]

      # Build the UI, which is baked into the final binary when the builtinassets
      # tag is set.
      cd "internal/web/ui" do
        system "yarn"
        system "yarn", "run", "build"
      end

      system "go", "build", *args, "-o", bin/"alloy", "."

      (buildpath/"config.alloy").write <<~EOS
        logging {
          level  = "info"
          format = "logfmt"
        }
      EOS

      (etc/"alloy").install "config.alloy"
      mkdir_p (var/"lib/alloy/data")
    end

    def caveats
      <<~EOS
        Alloy uses a configuration file that you can customize before running:
          #{etc}/alloy/config.alloy
      EOS
    end

    service do
      run [
        opt_bin/"alloy", "run", etc/"alloy/config.alloy",
        "--server.http.listen-addr=127.0.0.1:12345",
        "--storage.path=#{var}/lib/alloy/data",
      ]
      keep_alive true
      log_path var/"log/alloy.log"
      error_log_path var/"log/alloy.err.log"
    end

    test do
      assert_match version.to_s, shell_output("#{bin}/alloy --version")

      port = free_port

      (testpath/"config.alloy").write <<~EOS
        logging {
          level = "info"
        }
      EOS

      fork do
        exec bin/"alloy", "run", "#{testpath}/config.alloy",
          "--server.http.listen-addr=127.0.0.1:#{port}",
          "--storage.path=#{testpath}/data"
      end
      sleep 10

      output = shell_output("curl -s 127.0.0.1:#{port}/metrics")
      assert_match "alloy_build_info", output
    end
  end