nameko-chassis 3.1.0

nameko-chassis provides an opinionated base class for building resilient, observable microservices.

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nameko-chassis provides an opinionated base class for building resilient, observable microservices with the nameko framework.

nameko-chassis releases and distributed tracing

We’ve changed the approach to distributed tracing over a few releases. Here’s an overview:

• 0.9.0 supports only nameko 2 and has Zipkin integration

• 1.0 supports both nameko 2 and 3 RC, while dropping Zipkin. If you need Zipkin support and your service is still on nameko 2, either stay on nameko-chassis 0.9, or upgrade to 1.x and manage nameko-zipkin yourself.

• 2.0 supports only nameko v3 and provides a predefined OpenTelemetry integration to base Service class. You can still use OpenTelemetry with nameko-chassis 1.0 (provided you’re using nameko 3), but before 2.0 you’ll need to set it up yourself.

Features

By using nameko_chassis.service.Service, you’ll get:

• error reporting using Sentry

• integrated metrics endpoint for Prometheus

• helpers for service discovery

• partial* support for OpenTelemetry tracing

*You’ll need to call the instrumentors yourself, but we provide basic configuration as a dependency provider.

Installation

pip install nameko-chassis

You can also install the in-development version with:

pip install https://github.com/Emplocity/nameko-chassis/archive/master.zip

Usage

Base service class

from nameko.rpc import rpc
from nameko_chassis.service import Service


class MyService(Service):
    name = "my_service"

    @rpc
    def my_method(self):
        try:
            do_something()
        except Exception:
            self.sentry.captureException()

Note

If the RPC method raises an unhandled exception, nameko-sentry will automatically capture it to Sentry. The example above demonstrates the case when one wants to access the client manually.

Distributed tracing

Since nameko-chassis 2.0, we provide an opinionated setup of OpenTelemetry. Your services will export traces over HTTP to an endpoint defined in OTEL_EXPORTER_OTLP_ENDPOINT environment variable. However, you need to call instrumentors yourself, for example:

from nameko_chassis.service import Service
from nameko_opentelemetry import NamekoInstrumentor
from opentelemetry.instrumentation.logging import LoggingInstrumentor

LoggingInstrumentor().instrument()

NamekoInstrumentor().instrument(
    send_headers=True,
    send_request_payloads=True,
    send_response_payloads=True,
    max_truncate_length=1000,
)

class MyService(Service):
    name = "my_service"

Note

We chose HTTP over GRPC due to incompatibilities between eventlet and grpc with regards to asynchronous runtime.

Backdoor debugging

nameko-chassis.debug includes helpers for introspecting running services with nameko backdoor feature. For example if your service exposes backdoor on port 12345:

$ rlwrap nc -v localhost 12345
Connection to localhost 12345 port [tcp/*] succeeded!
Python 3.8.8 (default, Mar 23 2021, 11:02:14)
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from nameko_chassis.debug import debug_runner
>>> debug_runner(runner)
╭──────────────────────────── sleeping_http_service ───────────────────────────╮
│ 19 entrypoints                                                               │
│ 15 dependencies                                                              │
│ running 1/10 worker threads                                                  │
│ ╭────────────────── Thread #0: SleepingHttpService.sleep ──────────────────╮ │
│ │                                                                          │ │
│ │ Args: ["<Request 'http://127.0.0.1:8000/sleep/500' [GET]>"]              │ │
│ │ Kwargs: {'duration': '500'}                                              │ │
│ │ Context data: {'X-B3-ParentSpanId': '1058ef878ab0fe32'}                  │ │
│ │                                                                          │ │
│ │ Traceback:                                                               │ │
│ │   File                                                                   │ │
│ │ "/home/zbigniewsiciarz/v/sleephttp/lib/python3.8/site-packages/eventlet… │ │
│ │ line 221, in main                                                        │ │
│ │     result = function(*args, **kwargs)                                   │ │
│ │   File                                                                   │ │
│ │ "/home/zbigniewsiciarz/v/sleephttp/lib/python3.8/site-packages/nameko/c… │ │
│ │ line 392, in _run_worker                                                 │ │
│ │     result = method(*worker_ctx.args, **worker_ctx.kwargs)               │ │
│ │   File "./app/service.py", line 73, in sleep                             │ │
│ │     time.sleep(duration)                                                 │ │
│ │   File                                                                   │ │
│ │ "/home/zbigniewsiciarz/v/sleephttp/lib/python3.8/site-packages/eventlet… │ │
│ │ line 36, in sleep                                                        │ │
│ │     hub.switch()                                                         │ │
│ │   File                                                                   │ │
│ │ "/home/zbigniewsiciarz/v/sleephttp/lib/python3.8/site-packages/eventlet… │ │
│ │ line 313, in switch                                                      │ │
│ │     return self.greenlet.switch()                                        │ │
│ │                                                                          │ │
│ ╰──────────────────────────────────────────────────────────────────────────╯ │
╰──────────────────────────────────────────────────────────────────────────────╯

Note

Pretty printing like in the above example requires rich.

Documentation

https://nameko-chassis.readthedocs.io/

Development

To run the all tests run:

tox

Authors

nameko-chassis is developed and maintained by Emplocity.

License

This work is released under the Apache 2.0 license.