Chocs-Trace

Http tracing middleware for chocs library.

Installation

Poetry:

poetry add chocs-middleware.trace

Pip:

pip install chocs-middleware.trace

Features

• Automatic generation and propagation of tracing headers (x-request-id, x-correlation-id, x-causation-id)
• Sentry integration
• More intuitive log formatting options
• Structured logging

Usage

Support tracing in your responses

from chocs_middleware.trace import TraceMiddleware
from chocs import Application, HttpRequest, HttpResponse

# id_prefix will ensure generated tracing headers to contain your prefix
app = Application(TraceMiddleware(id_prefix="service-name-"))


@app.get("/hello")
def say_hello(req: HttpRequest) -> HttpResponse:
    return HttpResponse("Hello!")  # tracing middleware will automatically attach x-request-id, x-correlation-id, x-causation-id headers to your response

Tracing requests

from chocs_middleware.trace import TraceMiddleware, HttpStrategy
from chocs import Application, HttpRequest, HttpResponse
import requests

# http_strategy will try to detect requests library and use it to add tracing headers in all your requests
# if it fails to detect requests library it will fallback to urllib3
app = Application(TraceMiddleware(http_strategy=HttpStrategy.AUTO))


@app.get("/hello")
def say_hello(req: HttpRequest) -> HttpResponse:
    
    requests.get("http://example.com/test")  # middleware will automatically attach x-correlation-id, x-causation-id and x-request-id headers to your request
    
    return HttpResponse("Hello!")

# when using the requests.request method you will need to add headers for it to use, otherwise it will generate default headers and is unable to attach x-correlation-id, x-causation-id and x-request-id headers
@app.get("/test")
    def say_hello(req: HttpRequest, headers=req.headers) -> HttpResponse:
        response = requests.request("GET", "http://test.com/")
        assert response.content == b"ok"

        return HttpResponse("OK")

Using logger

from chocs import Application, HttpRequest, HttpResponse
from chocs_middleware.trace import TraceMiddleware, Logger

app = Application(TraceMiddleware())


@app.get("/hello")
def say_hello(req: HttpRequest) -> HttpResponse:
    logger = Logger.get("logger_name")
    logger.info("Hello {name}!", name="Bob")  # will output to log stream Hello Bob!
    return HttpResponse("Hello!")

Formatting message

from chocs import Application, HttpRequest, HttpResponse
from chocs_middleware.trace import TraceMiddleware, Logger

app = Application(TraceMiddleware())


@app.get("/hello")
def say_hello(req: HttpRequest) -> HttpResponse:
    logger = Logger.get("logger_name", message_format="[{level}] {tags.request.x-correlation-id} {msg}")
    logger.info("Hello {name}!", name="Bob")  # will output to log stream Hello Bob!
    return HttpResponse("Hello!")

Available formatting options

Name	Example value	Description
{level}	DEBUG	Log level name
{msg}	Example message	Log message after interpolation
{log_message}	Example {name}	Log message before interpolation
{timestamp}	2022-03-07T20:06:23.453866	Time of the logged message
{filename}	example.py	Name of the python file where message was log
{funcName}	example_function	Name of the function where message was log
{module}	example_module	Name of the module where message was log
{pathname}	example/path	Path name of the file where message was log
{tags.*}	some value	Custom tag value set by calling Logger.set_tag function