opentelemetry全链路初探--python注入

it排球君2025-11-12 11:01

前言

经过上一节，opentelemetry的基本操作都已经融会贯通，但是有位老哥提出疑问？我的代码都已经写完了，为了添加全链路，还需要重构之前的代码吗？那这个代价太大了。那本章就来讨论一下opentelemetry的注入的问题

本小节主要关注python注入

使用装饰器

使用装饰器的好处就是非常灵活，并且对代码入侵很小，只需要装饰一下即可

decoration-s1.py

复制代码 
import tornado.httpserver as httpserver
import tornado.web
from tornado.ioloop import IOLoop
from opentelemetry import trace
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.resources import SERVICE_NAME, Resource
from opentelemetry.sdk.trace.export import BatchSpanProcessor
from opentelemetry.exporter.otlp.proto.http.trace_exporter import OTLPSpanExporter
from opentelemetry.trace import get_tracer


trace.set_tracer_provider(
    TracerProvider(resource=Resource.create({SERVICE_NAME: "decoration-s1"}))
)
span_processor = BatchSpanProcessor(OTLPSpanExporter(endpoint="http://127.0.0.1:4318/v1/traces"))
trace.get_tracer_provider().add_span_processor(span_processor)


def traced(name):
    def decorator(func):
        def wrapper(*args, **kwargs):
            tracer = get_tracer(__name__)
            with tracer.start_as_current_span(name):
                return func(*args, **kwargs)
        return wrapper
    return decorator

class TestFlow(tornado.web.RequestHandler):
    def get(self):
        views()
        self.finish('hello world')

@traced("phase-1")
def views():
    pass

def applications():
    urls = []
    urls.append([r'/', TestFlow])
    return tornado.web.Application(urls)

def main():
    app = applications()
    server = httpserver.HTTPServer(app)
    server.bind(10000, '0.0.0.0')
    server.start(1)
    IOLoop.current().start()


if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt as e:
        IOLoop.current().stop()
    finally:
        IOLoop.current().close()

查看jaeger：

串联多个span

改造decoration-s1.py

复制代码 
...
@traced("phase-1")
def views():
    views_2()

@traced("phase-2")
def views_2():
    pass
...

跨服务串联span

改造decoration-s1.py

复制代码 
...
@traced("phase-1")
def views():
    views_2()
    headers = {}
    inject(headers)
    requests.get("http://127.0.0.1:20000", headers=headers)

@traced("phase-2")
def views_2():
    pass

...

新增decoration-s2.py

复制代码 
import tornado.httpserver as httpserver
import tornado.web
from tornado.ioloop import IOLoop
from opentelemetry import trace
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.resources import SERVICE_NAME, Resource
from opentelemetry.sdk.trace.export import BatchSpanProcessor
from opentelemetry.exporter.otlp.proto.http.trace_exporter import OTLPSpanExporter
from opentelemetry.trace import get_tracer
from opentelemetry.propagate import extract


trace.set_tracer_provider(
    TracerProvider(resource=Resource.create({SERVICE_NAME: "decoration-s2"}))
)
span_processor = BatchSpanProcessor(OTLPSpanExporter(endpoint="http://127.0.0.1:4318/v1/traces"))
trace.get_tracer_provider().add_span_processor(span_processor)


def traced(name):
    def decorator(func):
        def wrapper(*args, **kwargs):
            tracer = get_tracer(__name__)
            ctx = extract(args[0])
            with tracer.start_as_current_span(name, context=ctx):
                return func(*args, **kwargs)
        return wrapper
    return decorator

class TestFlow(tornado.web.RequestHandler):
    def get(self):
        views(self.request.headers)
        self.finish('hello world')

@traced("phase-3")
def views(headers):
    pass

def applications():
    urls = []
    urls.append([r'/', TestFlow])
    return tornado.web.Application(urls)

def main():
    app = applications()
    server = httpserver.HTTPServer(app)
    server.bind(20000, '0.0.0.0')
    server.start(1)
    IOLoop.current().start()


if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt as e:
        IOLoop.current().stop()
    finally:
        IOLoop.current().close()

查看jaeger，跨服务已经串联

自动注入 opentelemetry-instrumentation

opentelemetry-instrumentation可以自动采集在代码在不同阶段的trace

复制代码 
pip3 install opentelemetry-instrumentation opentelemetry-distro opentelemetry-exporter-otlp
opentelemetry-bootstrap -a install

查看支持的自动采集

复制代码 
▶ pip3 list | grep instrument
opentelemetry-instrumentation                0.56b0
opentelemetry-instrumentation-aiohttp-client 0.56b0
opentelemetry-instrumentation-aiohttp-server 0.56b0
opentelemetry-instrumentation-asyncio        0.56b0
opentelemetry-instrumentation-click          0.56b0
opentelemetry-instrumentation-dbapi          0.56b0
opentelemetry-instrumentation-elasticsearch  0.56b0
opentelemetry-instrumentation-flask          0.56b0
opentelemetry-instrumentation-grpc           0.56b0
opentelemetry-instrumentation-httpx          0.56b0
opentelemetry-instrumentation-jinja2         0.56b0
opentelemetry-instrumentation-kafka-python   0.56b0
opentelemetry-instrumentation-logging        0.56b0
opentelemetry-instrumentation-openai-v2      2.1b0
opentelemetry-instrumentation-pymysql        0.56b0
opentelemetry-instrumentation-redis          0.56b0
opentelemetry-instrumentation-requests       0.56b0
opentelemetry-instrumentation-sqlite3        0.56b0
opentelemetry-instrumentation-system-metrics 0.56b0
opentelemetry-instrumentation-threading      0.56b0
opentelemetry-instrumentation-tornado        0.56b0
opentelemetry-instrumentation-tortoiseorm    0.56b0
opentelemetry-instrumentation-urllib         0.56b0
opentelemetry-instrumentation-urllib3        0.56b0
opentelemetry-instrumentation-wsgi           0.56b0

可以看到，包括常见的mysql、redis、http requests等，都可以自动采集。来验证一下

auto-s1.py

复制代码 
from tornado.ioloop import IOLoop
import tornado.httpserver as httpserver
import tornado.web
import redis
import pymysql
import requests

class TestFlow(tornado.web.RequestHandler):
    def get(self):
        views()
        self.finish('hello world')

def views():
    get_redis()
    get_db()
    get_s2()

def get_redis():
    r = redis.StrictRedis(host='localhost', port=6379, db=0)
    r.set('name', 'hello')

def get_db():
    db = pymysql.connect(host='localhost', user='root', password='123456')
    cursor = db.cursor()
    cursor.execute("SELECT VERSION()")
    data = cursor.fetchone()
    db.close()

def get_s2():
    requests.get('http://127.0.0.1:20000')

def applications():
    urls = []
    urls.append([r'/', TestFlow])
    return tornado.web.Application(urls)

def main():
    app = applications()
    server = httpserver.HTTPServer(app)
    server.bind(10000, '0.0.0.0')
    server.start(1)
    IOLoop.current().start()


if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt as e:
        IOLoop.current().stop()
    finally:
        IOLoop.current().close()

用opentelemetry-instrumentation启动auto-s1.py

复制代码 
▶ opentelemetry-instrument \
    --traces_exporter otlp \
    --service_name auto-s1 \
    --exporter_otlp_endpoint http://0.0.0.0:4317 \
    python3 auto-s1.py

auto-s2.py

复制代码 
from tornado.ioloop import IOLoop
import tornado.httpserver as httpserver
import tornado.web

class TestFlow(tornado.web.RequestHandler):
    def get(self):
        views()
        self.finish('hello world')

def views():
    pass

def applications():
    urls = []
    urls.append([r'/', TestFlow])
    return tornado.web.Application(urls)

def main():
    app = applications()
    server = httpserver.HTTPServer(app)
    server.bind(20000, '0.0.0.0')
    server.start(1)
    IOLoop.current().start()


if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt as e:
        IOLoop.current().stop()
    finally:
        IOLoop.current().close()

同理，用opentelemetry-instrumentation启动auto-s2.py

复制代码 
▶ opentelemetry-instrument \
    --traces_exporter otlp \
    --service_name auto-s2 \
    --exporter_otlp_endpoint http://0.0.0.0:4317 \
    python3 auto-s2.py

已经看到整个完整的链路追踪了

opentelemetry-instrument与装饰器结合使用

由于opentelemetry-instrument不能跟踪自定义的模块，可以结合装饰器跟踪重点函数

修改一下auto-s1.py

复制代码 
...
from opentelemetry import trace
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import BatchSpanProcessor
from opentelemetry.exporter.otlp.proto.http.trace_exporter import OTLPSpanExporter

trace.set_tracer_provider(TracerProvider())
tracer = trace.get_tracer(__name__)
span_processor = BatchSpanProcessor(OTLPSpanExporter(endpoint="http://127.0.0.1:4318/v1/traces"))
trace.get_tracer_provider().add_span_processor(span_processor)

def traced_function(func):
    def wrapper(*args, **kwargs):
        with tracer.start_as_current_span(func.__name__):
            return func(*args, **kwargs)
    return wrapper

...

def views():
    get_redis()
    get_db()
    get_important()
    get_s2()

@traced_function
def get_important():
    pass

...

小结

本节介绍了2种注入的方法

  • 其中装饰器的方法，提前将trace流程写好，函数只需要调用装饰即可完成注入，减少了代码入侵度
  • 而opentelemetry-instrument则是采用aop思想，将目标模块（比如pymysql、requests等）动态替换成预定义的模块，从而实现trace的注入，该方法的优点就是对业务代码的无入侵
  • 在python中，结合以上两种方法，可以很好的完成trace注入

联系我

  • 联系我，做深入的交流

至此，本文结束

在下才疏学浅，有撒汤漏水的，请各位不吝赐教...

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