在追踪应用的链路数据之前，您需要通过客户端将应用数据上报至可观测链路 OpenTelemetry 版服务端。本文介绍如何通过OpenTelemetry Ruby SDK上报Ruby应用数据。

前提条件

获取接入点信息
  1. 登录可观测链路 OpenTelemetry 版控制台。
  2. 在左侧导航栏单击集群配置，然后在右侧页面单击接入点信息页签。
  3. 在页面顶部选择需要接入的地域，然后在集群信息区域打开显示Token开关。
  4. 在客户端采集工具区域单击OpenTelemetry。
    在下方表格的相关信息列中，获取接入点信息。OT接入点信息
    说明 如果应用部署于阿里云生产环境，则选择阿里云VPC网络接入点，否则选择公网接入点。

示例Demo

示例代码仓库地址：ruby-opentelemetry-demo

方法一：使用HTTP协议上报数据

  1. 安装手动埋点所需的OpenTelemetry相关依赖。
    gem install opentelemetry-api
gem install opentelemetry-sdk
gem install opentelemetry-exporter-otlp
  2. OpenTelemetry初始化。
    添加导出观测数据的组件，将<endpoint>替换成前提条件中获取的对应地域的Endpoint。
    require 'opentelemetry/sdk'
require 'opentelemetry-exporter-otlp'

OpenTelemetry::SDK.configure do |c|
  c.add_span_processor(
    OpenTelemetry::SDK::Trace::Export::BatchSpanProcessor.new(
      OpenTelemetry::Exporter::OTLP::Exporter.new(
        endpoint: '<endpoint>' # HTTP方式接入
      )
    )
  )
  c.resource = OpenTelemetry::SDK::Resources::Resource.create({
    OpenTelemetry::SemanticConventions::Resource::SERVICE_NAMESPACE => 'tracing',
    OpenTelemetry::SemanticConventions::Resource::SERVICE_NAME => 'ruby_demo', # 通过OpenTelemetry上报的Ruby应用名
    OpenTelemetry::SemanticConventions::Resource::SERVICE_VERSION => '0.0.1',
  })
end
  3. 获取Tracer并创建新的Span。
    tracer = OpenTelemetry.tracer_provider.tracer('<your_tracer_name>', '0.1.0')

tracer.in_span('parent_span') do |parent_span|
  # ...
end
  4. 获取当前Span，向当前Span添加信息并获取Trace ID和Span ID。
    # ...
tracer.in_span('parent_span') do |parent_span|
  # current_span即parent_span
  current_span = OpenTelemetry::Trace::current_span
  current_span.set_attribute('key', 'value')
  pp current_span.context.trace_id
  pp current_span.context.span_id
end
  5. 创建嵌套的Span。
    # ...
tracer.in_span('parent_span') do |parent_span|
  # ...
  tracer.in_span('child_span') do |child_span|
    # 此时current_span是child_span
    current_span = OpenTelemetry::Trace::current_span
    pp current_span
  end
end
    展开查看完整代码
    require 'opentelemetry/sdk'
require 'opentelemetry-exporter-otlp'

OpenTelemetry::SDK.configure do |c|
  c.add_span_processor(
    OpenTelemetry::SDK::Trace::Export::BatchSpanProcessor.new(
      OpenTelemetry::Exporter::OTLP::Exporter.new(
        endpoint: '<endpoint>' # HTTP方式接入
      )
    )
  )
  c.resource = OpenTelemetry::SDK::Resources::Resource.create({
    OpenTelemetry::SemanticConventions::Resource::SERVICE_NAMESPACE => 'tracing',
    OpenTelemetry::SemanticConventions::Resource::SERVICE_NAME => 'ruby_demo', # 通过OpenTelemetry上报的Ruby应用名
    OpenTelemetry::SemanticConventions::Resource::SERVICE_VERSION => '0.0.1',
  })

  # 不使用OpenTelemetry Resources API来设置应用名
  # c.service_name = 'ruby_demo'
end

tracer = OpenTelemetry.tracer_provider.tracer('instrumentation_library_name', '0.1.0')

tracer.in_span('parent_span') do |parent_span|
  # 设置Attribute
  parent_span.set_attribute('language', 'ruby')
  parent_span.set_attribute("attribute_key", ["attribute_value1", "attribute_value1", "attribute_value1"])
  # 添加Event
  parent_span.add_event("event", attributes: {
    "pid" => 1234,
    "signal" => "SIGHUP"
  })

  # 获取Trace ID与当前Span的Span ID
  current_span = OpenTelemetry::Trace::current_span
  pp current_span.context.trace_id
  pp current_span.context.span_id

  tracer.in_span('child_span') do |child_span|
    child_span.add_attributes({
      "key1" => "value1",
      "key2" => "value2"
    })

    child_span.add_event("mock exception here")

    begin
      raise 'An error has occurred'
    rescue
      # 发生异常时，将child_span的status设置为error
      child_span.status = OpenTelemetry::Trace::Status.error("error in child span")
    end

    pp child_span

  end
end

sleep 10
  6. 运行程序。
    ruby manual.rb

方法二：自动上报

OpenTelemetry Ruby也可以自动在应用程序中埋点，实现自动观测。下面以基于Rails框架的Ruby Web应用为例，演示使用OpenTelemetry自动追踪链路并上报数据。

  1. 下载开源Web应用框架Rails。
    gem install rails
  2. 使用Rails创建Web项目。
    rails new <your-project-name>
    • 请将<your-project-name>替换为应用名，例如：rails new auto-demo。
    • 如果运行命令后出现Rails is not currently installed on this system.的报错，请关闭终端并重新打开，然后在新打开的终端中重新输入命令。
  3. 在应用目录下的Gemfile文件中添加以下内容。
    gem 'opentelemetry-sdk'
gem 'opentelemetry-exporter-otlp'
gem 'opentelemetry-instrumentation-all'
  4. 下载此Web应用所需的第三方依赖。
    1. 进入项目根目录。
      cd <your-project-name>
    2. 下载Ruby依赖管理工具Bundler。
      gem install bundler
    3. 下载Gemfile中的依赖。
      bundle install
  5. 在<your-project-name>/config/initializers目录下创建opentelemetry.rb文件，并添加以下内容。
    # config/initializers/opentelemetry.rb
require 'opentelemetry/sdk'
require 'opentelemetry/exporter/otlp'
require 'opentelemetry/instrumentation/all'

OpenTelemetry::SDK.configure do |c|
  c.add_span_processor(
    OpenTelemetry::SDK::Trace::Export::BatchSpanProcessor.new(
      OpenTelemetry::Exporter::OTLP::Exporter.new(
        endpoint: '<endpoint>' # HTTP方式接入
      )
    )
  )
  c.resource = OpenTelemetry::SDK::Resources::Resource.create({
    OpenTelemetry::SemanticConventions::Resource::HOST_NAME => '<your-host-name>', # 主机名
  })
  c.service_name = '<your-service-name>'    # 服务名
  c.use_all()    # 自动观测opentelemetry支持的所有库，
end
    • 将<endpoint>替换成前提条件中获取的对应地域的Endpoint。
    • 根据实际情况替换<your-host-name>和<your-service-name>。
  6. 运行项目。
    rails server
    如果输出以下内容，则表示运行成功。
    * Puma version: 5.6.5 (ruby 2.7.2-p137) ("Birdie's Version")
*  Min threads: 5
*  Max threads: 5
*  Environment: development
*          PID: 79842
* Listening on http://127.0.0.1:3000
* Listening on http://[::1]:3000
Use Ctrl-C to stop
  7. 在浏览器中访问http://127.0.0.1:3000，终端输出以下内容则说明数据已上报至可观测链路 OpenTelemetry 版控制台。
    Started GET "/" for 127.0.0.1 at 2023-01-01 10:00:00 +0800
Processing by Rails::WelcomeController#index as HTML
  Rendering /Users/username/.rvm/gems/ruby-2.7.2/gems/railties-7.0.4.3/lib/rails/templates/rails/welcome/index.html.erb
  Rendered /Users/username/.rvm/gems/ruby-2.7.2/gems/railties-7.0.4.3/lib/rails/templates/rails/welcome/index.html.erb (Duration: 0.8ms | Allocations: 665)
Completed 200 OK in 6ms (Views: 2.1ms | ActiveRecord: 0.0ms | Allocations: 5440)

查看监控数据

在可观测链路 OpenTelemetry 版控制台的应用列表页面选择目标应用，查看链路数据。