Create custom spans - Function Compute - Alibaba Cloud Documentation Center

After you enable Tracing Analysis for a service, Function Compute records the time consumed in the system. The time includes the cold start time, execution time of Initializer hooks, and execution time of functions. To record the time consumed for functions on the business side, you can create custom spans. For example, you can record the time taken to access services such as ApsaraDB RDS and File Storage NAS (NAS) within functions. This topic describes how to use Serverless Devs to create a custom span.

Prerequisites

Procedure

You can create custom spans based on traces of Function Compute and connect the custom spans to the traces of Function Compute. Tracing Analysis for Function Compute allows you to create custom spans based on the Jaeger implementation of the OpenTracing specification by using the following methods:

Use the SDK for Jaeger
Use OpenTelemetry

For more information about Jaeger and OpenTelemetry, see Jaeger and OpenTelemetry.

The two methods involve the following steps:

Add Jaeger or OpenTelemetry dependencies to the function. For more information about how to add third-party dependencies, see Install third-party dependencies for a function.
Obtain the SpanContext of the trace of Function Compute from the function, create custom spans based on the SpanContext of Function Compute, and then add instrumentation before and after the code fragments whose execution time needs to be recorded.
View the trace information on the Tracing Analysis tab of the Function Details page in the Function Compute console or in the Tracing Analysis console.

Use the SDK for Jaeger

The following topics provide the sample code that is used to create custom spans by using the SDK for Jaeger in the supported runtime environments:

This section describes how to use Serverless Devs to create a custom span, and create and deploy a function in a Node.js runtime environment.

Note

You can use Serverless Devs to install dependencies and package and deploy code to Function Compute. You can also package and deploy code in other ways. For more information about Serverless Devs, see What is Serverless Devs?.

Create a code directory.
```
mkdir jaeger-demo
```
Initialize a Node.js runtime template.
1. Run the following command to go to the code directory:
```
cd jaeger-demo
```
2. Run the following command in the code directory to initialize the Node.js 12 project:
```
s init devsapp/start-fc-event-nodejs12
```
  Sample output:
```
 Serverless Awesome: https://github.com/Serverless-Devs/package-awesome

 Please input your project name (init dir) (start-fc-event-nodejs12)
```
3. Specify a name for the project, and press the Enter key.
  By default, Serverless Devs generates a project named start-fc-event-nodejs12. You can modify the name of the project based on your business requirements. In this example, the default project name is used.
  Sample output:
```
 Serverless Awesome: https://github.com/Serverless-Devs/package-awesome

 Please input your project name (init dir) start-fc-event-nodejs12
 file decompression completed
 please select credential alias (Use arrow keys)
❯ default
```
4. Select an alias and press the Enter key.
5. Specify whether to deploy the project based on your business requirements.
  Dependencies must be installed for the project in this example. Therefore, after Do you want to deploy the project immediately? (Y/n) is returned in the command output, enter n.
Run the following command to go to the code directory of the project:
```
cd start-fc-event-nodejs12/code
```

Run the following command in the code directory to initialize the package.json file:

npm init -y

Sample output:

Wrote to /test/jjyy/start-fc-event-nodejs12/code/package.json:

{
  "name": "code",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

Run the following command to install Jaeger dependencies:
```
npm i jaeger-client --save
```
Sample output:
```
added 15 packages in 1s
```

Write function code.

The following code is used:

var initTracer = require('jaeger-client').initTracer;
var spanContext = require('jaeger-client').SpanContext;


module.exports.handler = function(event, context, callback) 
{
    console.log('invoking...',context.tracing);

    var config = {
        serviceName: 'e2e-test',
        reporter: {
            // Provide the traces endpoint; this forces the client to connect directly to the Collector and send
            // spans over HTTP
            collectorEndpoint: context.tracing.jaegerEndpoint,
            flushIntervalMs: 10,
        },
        sampler: {
            type: "const",
            param: 1
        },
    };
    var options = {
        tags: {
            'version': 'fc-e2e-tags',
        },
    };
    var tracer = initTracer(config, options);
    var invokSpanContextStr = context.tracing.openTracingSpanContext;
    console.log('spanContext', invokSpanContextStr);
    var invokSpanContext = spanContext.fromString(invokSpanContextStr);
    var span = tracer.startSpan("CustomSpan", {
        childOf: invokSpanContext
    });
    span.finish();
    var params = {
        openTracingSpanContext: context.tracing.openTracingSpanContext,
        openTracingSpanBaggages: context.tracing.openTracingSpanBaggages,
        jaegerEndpoint: context.tracing.jaegerEndpoint
    }
   callback(null,'success')
}

Edit the s.yaml file.

Run the following command to go to the project directory:
```
cd ..
```

Run the following command to edit the s.yaml file:

vim s.yaml

The following sample code provides an example of the file.

edition: 1.0.0
name: hello-world-app
access: default

vars: # The global variable.
  region: "cn-hangzhou"
  service:
    name: "hello-world-service"
    description: 'hello world by serverless devs'
    tracingConfig: Enable # Enable Tracing Analysis.

services:
  helloworld: # The name of the service or module.
    component: fc # The name of the component. Serverless Devs is similar to a game console, which must be used with game cards to play games. Components are similar to game cards. Game players can insert different game cards into a game console to play different games. Likewise, different components can be used to obtain different business capabilities.
    props:
      region: ${vars.region} # For more information about how to use variables, visit: https://www.serverless-devs.com/serverless-devs/yaml.
      service: ${vars.service}
      function:
        name: "start-fc-event-nodejs14"
        description: 'hello world by serverless devs'
        runtime: nodejs12
        codeUri: ./code
        handler: index.handler
        memorySize: 128
        timeout: 60

Run the following command to install dependencies:

s build --use-docker

Sample output:

[2021-11-12T18:33:43.856] [INFO ] [S-CLI] - Start ...
[2021-11-12T18:33:44.677] [INFO ] [FC-BUILD] - Build artifact start...
[2021-11-12T18:33:44.701] [INFO ] [FC-BUILD] - Use docker for building.
[2021-11-12T18:33:44.988] [INFO ] [FC-BUILD] - Build function using image: registry.cn-beijing.aliyuncs.com/aliyunfc/runtime-nodejs12:build-1.9.21
[2021-11-12T18:33:45.011] [INFO ] [FC-BUILD] - skip pulling image registry.cn-beijing.aliyuncs.com/aliyunfc/runtime-nodejs12:build-1.9.21...
[2021-11-12T18:33:47.915] [INFO ] [FC-BUILD] - Build artifact successfully.

Tips for next step
======================
* Invoke Event Function: s local invoke
* Invoke Http Function: s local start
* Deploy Resources: s deploy
End of method: build

Run the following command to deploy the project:

s deploy -y

Sample output:

[2021-11-12T18:35:26.015] [INFO ] [S-CLI] - Start ...
[2021-11-12T18:35:26.633] [INFO ] [FC-DEPLOY] - Using region: cn-hangzhou
[2021-11-12T18:35:26.634] [INFO ] [FC-DEPLOY] - Using access alias: default
[2021-11-12T18:35:26.634] [INFO ] [FC-DEPLOY] - Using accessKeyID: LTAI4G4cwJkK4Rza6xd9****
......
 Make service fc-deploy-service success.
 Make function fc-deploy-service/event-nodejs12 success.
[2021-11-12T18:35:37.661] [INFO ] [FC-DEPLOY] - Checking Service fc-deploy-service exists
[2021-11-12T18:35:37.718] [INFO ] [FC-DEPLOY] - Checking Function event-nodejs12 exists

Tips for next step
======================
* Display information of the deployed resource: s info
* Display metrics: s metrics
* Display logs: s logs
* Invoke remote function: s invoke
* Remove Service: s remove service
* Remove Function: s remove function
* Remove Trigger: s remove trigger
* Remove CustomDomain: s remove domain



fc-deploy-test:
  region:   cn-hangzhou
  service:
    name: fc-deploy-service
  function:
    name:       event-nodejs12
    runtime:    nodejs12
    handler:    index.handler
    memorySize: 128
    timeout:    60

Verify the results.
View the trace in the Function Compute console. The custom span that you created is connected to the spans of Function Compute.

Use OpenTelemetry

The following topics provide the sample code that is used to create custom spans by using OpenTelemetry in the supported runtime environments:

This section describes how to use Serverless Devs to create a custom span, and create and deploy a function in the Python runtime environment.

Note

Create a code directory.
```
mkdir opentelemetry-demo
```
Go to the code directory.
```
cd opentelemeytry-demo
```
Initialize a Python runtime template.
1. Run the following command to initialize the Python 3 project:
```
s init devsapp/start-fc-event-python3
```
  Sample command output:
```
 Serverless Awesome: https://github.com/Serverless-Devs/package-awesome

 Please input your project name (init dir) (start-fc-event-python3)
```
2. Specify a name for the project, and press the Enter key.
  By default, Serverless Devs generates a project named start-fc-event-python3. You can modify the name of the project based on your business requirements. In this example, the default project name is used.
  Sample output:
```
 Serverless Awesome: https://github.com/Serverless-Devs/package-awesome

 Please input your project name (init dir) start-fc-event-python3
 file decompression completed
 please select credential alias (Use arrow keys)
❯ default
```
3. Select an alias and press the Enter key.
4. Specify whether to deploy the project based on your business requirements.
  Dependencies must be installed for the project in this example. Therefore, after Do you want to deploy the project immediately? (Y/n) is returned in the command output, enter n.
Install OpenTelemetry dependencies.
1. Run the following command to go to the code directory:
```
cd start-fc-event-python3/code
```
2. Create the requirements.txt file in the code directory, and modify the file based on the following content:
```
opentelemetry-api==1.12.0
opentelemetry-sdk==1.12.0
opentelemetry-exporter-jaeger==1.12.0
```

Run the following command to write function code:

vim index.py

The following code is used:

# -*- coding: utf-8 -*-
import time
from opentelemetry import trace
from opentelemetry.exporter.jaeger.thrift import JaegerExporter
from opentelemetry.sdk.resources import SERVICE_NAME, Resource
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import SimpleSpanProcessor
from opentelemetry.trace import NonRecordingSpan

trace.set_tracer_provider(
    TracerProvider(
        resource=Resource.create({SERVICE_NAME: "my-helloworld-service"})
    )
)
tracer = trace.get_tracer(__name__)


def handler(event, context):
    init_tracer(context.tracing.jaeger_endpoint)
    span_context = get_fc_span(context.tracing.span_context)
    start_my_span(trace.set_span_in_context(NonRecordingSpan(span_context)))
    return 'hello world'


def init_tracer(endpoint):
    # create a JaegerExporter
    jaeger_exporter = JaegerExporter(
        collector_endpoint=endpoint
    )

    # Create a SimpleSpanProcessor and add the exporter to it
    span_processor = SimpleSpanProcessor(jaeger_exporter)

    # add to the tracer
    trace.get_tracer_provider().add_span_processor(span_processor)


def get_fc_span(jaeger_span_context):
    jaeger_span_context_arr = jaeger_span_context.split(":")
    tid = int(jaeger_span_context_arr[0], 16)
    sid = int(jaeger_span_context_arr[1], 16)

    span_context = trace.SpanContext(
        trace_id=tid,
        span_id=sid,
        is_remote=True,
        trace_flags=trace.TraceFlags(0x01),
    )
    return span_context


def start_my_span(context):
    with tracer.start_as_current_span(name="fc-operation", context=context):
        time.sleep(0.15)
        with tracer.start_as_current_span("child"):
            time.sleep(0.1)

After you edit the function code, enter :WQ and press the Enter key to exit the editing page.

Edit the s.yaml file.

Run the following command to go to the project directory:
```
cd ..
```

Run the following command to edit the s.yaml file:

vim s.yaml

The following sample code provides an example of the file.

edition: 1.0.0
name: hello-world-app
access: default

vars: # The global variable.
  region: "cn-hangzhou"
  service:
    name: "hello-world-service"
    description: 'hello world by serverless devs'
    tracingConfig: Enable # Enable Tracing Analysis.

services:
  helloworld: # The name of the service or module.
    component: fc # The name of the component. Serverless Devs is similar to a game console, which must be used with game cards to play games. Components are similar to game cards. Game players can insert different game cards into a game console to play different games. Likewise, different components can be used to obtain different business capabilities.
    props:
      region: ${vars.region} # For more information about how to use variables, visit: https://www.serverless-devs.com/serverless-devs/yaml#Variable value.
      service: ${vars.service}
      function:
        name: "start-fc-event-python3"
        description: 'hello world by serverless devs'
        runtime: python3.9
        codeUri: ./code
        handler: index.handler
        memorySize: 128
        timeout: 60

After you edit the code, enter :WQ and press the Enter key to exit the editing page.

Run the following command to install dependencies:

s build --use-docker

Sample output:

[2021-11-12T18:53:05.818] [INFO ] [S-CLI] - Start ...
[2021-11-12T18:53:06.638] [INFO ] [FC-BUILD] - Build artifact start...
[2021-11-12T18:53:06.659] [INFO ] [FC-BUILD] - Use docker for building.
[2021-11-12T18:53:06.888] [INFO ] [FC-BUILD] - Build function using image: registry.cn-beijing.aliyuncs.com/aliyunfc/runtime-python3.6:build-1.9.21
[2021-11-12T18:53:06.942] [INFO ] [FC-BUILD] - skip pulling image registry.cn-beijing.aliyuncs.com/aliyunfc/runtime-python3.6:build-1.9.21...
[2021-11-12T18:53:10.570] [INFO ] [FC-BUILD] - Build artifact successfully.

Tips for next step
======================
* Invoke Event Function: s local invoke
* Invoke Http Function: s local start
* Deploy Resources: s deploy
End of method: build

Run the following command to deploy the project:

s deploy -y

Sample output:

[2021-11-12T18:55:02.640] [INFO ] [S-CLI] - Start ...
[2021-11-12T18:55:03.455] [INFO ] [FC-DEPLOY] - Using region: cn-hangzhou
[2021-11-12T18:55:03.456] [INFO ] [FC-DEPLOY] - Using access alias: default
[2021-11-12T18:55:03.456] [INFO ] [FC-DEPLOY] - Using accessKeyID: LTAI4G4cwJkK4Rza6xd9****
[2021-11-12T18:55:03.457] [INFO ] [FC-DEPLOY] - Using accessKeySecret: eCc0GxSpzfq1DVspnqqd6nmYNN****
 Using fc deploy type: sdk, If you want to deploy with pulumi, you can [s cli fc-default set deploy-type pulumi] to switch.
[2021-11-12T18:55:04.142] [INFO ] [FC-DEPLOY] - Checking Service fc-deploy-service exists
[2021-11-12T18:55:04.722] [INFO ] [FC-DEPLOY] - Checking Function event-py3 exists
[2021-11-12T18:55:04.831] [INFO ] [FC-DEPLOY] - Fc detects that you have run build command for function: event-py3.
[2021-11-12T18:55:04.831] [INFO ] [FC-DEPLOY] - Using codeUri: /test/jjyy/opentelemetry-demo/start-fc-event-python3/.s/build/artifacts/fc-deploy-service/event-py3
[2021-11-12T18:55:04.835] [INFO ] [FC-DEPLOY] - Fc add/append some content to your origin environment variables for finding dependencies generated by build command.
{
  "LD_LIBRARY_PATH": "/code/.s/root/usr/local/lib:/code/.s/root/usr/lib:/code/.s/root/usr/lib/x86_64-linux-gnu:/code/.s/root/usr/lib64:/code/.s/root/lib:/code/.s/root/lib/x86_64-linux-gnu:/code/.s/root/python/lib/python2.7/site-packages:/code/.s/root/python/lib/python3.6/site-packages:/code:/code/lib:/usr/local/lib",
  "PATH": "/code/.s/root/usr/local/bin:/code/.s/root/usr/local/sbin:/code/.s/root/usr/bin:/code/.s/root/usr/sbin:/code/.s/root/sbin:/code/.s/root/bin:/code:/code/node_modules/.bin:/code/.s/python/bin:/code/.s/node_modules/.bin:/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/sbin:/bin",
  "NODE_PATH": "/code/node_modules:/usr/local/lib/node_modules",
  "PYTHONUSERBASE": "/code/.s/python"
}
 Make service fc-deploy-service success.
 Make function fc-deploy-service/event-py3 success.
[2021-11-12T18:55:10.693] [INFO ] [FC-DEPLOY] - Checking Service fc-deploy-service exists
[2021-11-12T18:55:10.737] [INFO ] [FC-DEPLOY] - Checking Function event-py3 exists

Tips for next step
======================
* Display information of the deployed resource: s info
* Display metrics: s metrics
* Display logs: s logs
* Invoke remote function: s invoke
* Remove Service: s remove service
* Remove Function: s remove function
* Remove Trigger: s remove trigger
* Remove CustomDomain: s remove domain



fc-deploy-test:
  region:   cn-hangzhou
  service:
    name: fc-deploy-service
  function:
    name:       event-py3
    runtime:    python3    handler:    index.handler
    memorySize: 128
    timeout:    60

Verify the results.
View the trace in the Function Compute console. The custom span that you created is connected to the spans of Function Compute.