Python Example¶

Install Dependency¶

Installing Python Flask

pip install flask

Installing DDTrace Python Function Library

pip install ddtrace

Note: This command requires pip version 18.0. 0 or higher. For Ubuntu, Debian, or other package management tools, upgrade the pip version using the following command:

pip install --upgrade pip

Code Example¶

#
# service_a.py
#

from flask import Flask, request
import requests, os
from ddtrace import tracer

app = Flask(__name__)

def shutdown_server():
    func = request.environ.get('werkzeug.server.shutdown')
    if func is None:
        raise RuntimeError('Not running with the Werkzeug Server')
    func()

@app.route('/a',  methods=['GET'])
def index():
    requests.get('http://127.0.0.1:54322/b')
    return 'OK', 200

@app.route('/stop',  methods=['GET'])
def stop():
    shutdown_server()
    return 'Server shutting down...\n'

# 启动 service A: HTTP 服务启动在 54321 端口上
if __name__ == '__main__':
    app.run(host="0.0.0.0", port=54321, debug=True)

#
# service_b.py
#


from flask import Flask, request
import os, time, requests
from ddtrace import tracer

app = Flask(__name__)

def shutdown_server():
    func = request.environ.get('werkzeug.server.shutdown')
    if func is None:
        raise RuntimeError('Not running with the Werkzeug Server')
    func()

@app.route('/b',  methods=['GET'])
def index():
    time.sleep(1)
    return 'OK', 200

@app.route('/stop',  methods=['GET'])
def stop():
    shutdown_server()
    return 'Server shutting down...\n'

# Start service B: The HTTP service starts on port 54322
if __name__ == '__main__':
    app.run(host="0.0.0.0", port=54322, debug=True)

Run¶

Take the Web Server Flask application commonly used in Python as an example. In the example, SERVICE_A provides the HTTP service and calls the SERVICE_B HTTP service.

Run SERVICE_A

DD_SERVICE=SERVICE_A \
DD_SERVICE_MAPPING=postgres:postgresql,defaultdb:postgresql \
DD_TAGS=project:your_project_name,env=test,version=v1 \
DD_AGENT_HOST=localhost \
DD_AGENT_PORT=9529 \
ddtrace-run python3 service_a.py &> a.log &

Run SERVICE_B

DD_SERVICE=SERVICE_B \
DD_SERVICE_MAPPING=postgres:postgresql,defaultdb:postgresql \
DD_TAGS=project:your_project_name,env=test,version=v1 \
DD_AGENT_HOST=localhost \
DD_AGENT_PORT=9529 \
ddtrace-run python3 service_b.py &> b.log &

Invoke the A service, causing it to invoke the B service, which produces the corresponding trace data (here you can perform multiple triggers)

curl http://localhost:54321/a

Stop both services separately

curl http://localhost:54321/stop
curl http://localhost:54322/stop

Environment Variable Support¶

DD_ENV: Set environment variables for the service.
DD_VERSION: APP version number.
DD_SERVICE: The service name used to set the application, which is passed when setting up middleware for Web framework integration such as Pylons, Flask, or Django. For Tracing without Web integration, it is recommended that you set the service name in your code.
DD_SERVICE_MAPPING: Define service name mappings for renaming services in Tracing.
DD_TAGS: Add default Tags for each Span.
DD_AGENT_HOST: The name of the address where Datakit listens, default localhost.
DD_AGENT_PORT: The port number on which Datakit listens, the default is 9529.
DD_TRACE_SAMPLE_RATE: Set the sampling rate from 0.0 (0%) to 1.0 (100%).

Python Example¶

Install Dependency¶

Code Example¶

Run¶

Environment Variable Support¶

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