This is an eureka client written in python, you can easily intergrate your python components with spring cloud.
Python 3.7+
From 0.9.0
, python 2 is no longer supported, if you are using python 2, please use version 0.8.12
.
pip install py_eureka_client
This is the easiest way to use this component.
import py_eureka_client.eureka_client as eureka_client
your_rest_server_port = 9090
# The flowing code will register your server to eureka server and also start to send heartbeat every 30 seconds
eureka_client.init(eureka_server="http://your-eureka-server-peer1,http://your-eureka-server-peer2",
app_name="your_app_name",
instance_port=your_rest_server_port)
Then, in your business code, use
import py_eureka_client.eureka_client as eureka_client
res = eureka_client.do_service("OTHER-SERVICE-NAME", "/service/context/path")
print("result of other service" + res)
You can also use the EurekaClient
class.
from py_eureka_client.eureka_client import EurekaClient
client = EurekaClient(eureka_server="http://my_eureka_server_peer_1/eureka/v2,http://my_eureka_server_peer_2/eureka/v2", app_name="python_module_1", instance_port=9090)
await client.start()
res = await client.do_service("OTHER-SERVICE-NAME", "/service/context/path")
print("result of other service" + res)
# when server is shutted down:
await client.stop()
In fact, the init
function is a facade of the EurekaClient, it holds a client object behind, you can get that by catching its return value or use eureka_client.get_client()
to get it. The init
function will automatically start the client, while using raw EurekaClient
, you must call the start()
and stop()
method explicitly.
From 0.11.0
, all the methods in EurekaClient
are defined async
, and there are also async facade for init
, do_servise
, stop
functions names init_async
, do_service_async
, sto_async
.
The most common method to will be like:
import py_eureka_client.eureka_client as eureka_client
your_rest_server_port = 9090
eureka_client.init(eureka_server="http://your-eureka-server-peer1,http://your-eureka-server-peer2",
app_name="python_module_1",
instance_port=your_rest_server_port)
But if you have deploy your eureka server in several zones, you should specify the eureka_availability_zones
parameter.
import py_eureka_client.eureka_client as eureka_client
eureka_client.init(eureka_availability_zones={
"us-east-1c": "http://ec2-552-627-568-165.compute-1.amazonaws.com:7001/eureka/v2/,http://ec2-368-101-182-134.compute-1.amazonaws.com:7001/eureka/v2/",
"us-east-1d": "http://ec2-552-627-568-170.compute-1.amazonaws.com:7001/eureka/v2/",
"us-east-1e": "http://ec2-500-179-285-592.compute-1.amazonaws.com:7001/eureka/v2/"},
zone="us-east-1c",
app_name="python_module_1",
instance_port=9090,
data_center_name="Amazon")
If you are looking for flexibility, you should configure Eureka service URLs using DNS.
For instance, following is a DNS TXT record created in the DNS server that lists the set of available DNS names for a zone.
txt.us-east-1.mydomaintest.netflix.net="us-east-1c.mydomaintest.netflix.net" "us-east-1d.mydomaintest.netflix.net" "us-east-1e.mydomaintest.netflix.net"
Then, you can define TXT records recursively for each zone similar to the following (if more than one hostname per zone, space delimit)
txt.us-east-1c.mydomaintest.netflix.net="ec2-552-627-568-165.compute-1.amazonaws.com" "ec2-368-101-182-134.compute-1.amazonaws.com"
txt.us-east-1d.mydomaintest.netflix.net="ec2-552-627-568-170.compute-1.amazonaws.com"
txt.us-east-1e.mydomaintest.netflix.net="ec2-500-179-285-592.compute-1.amazonaws.com"
And then you can create the client like:
import py_eureka_client.eureka_client as eureka_client
eureka_client.init(eureka_domain="mydomaintest.netflix.net",
region="us-east-1",
zone="us-east-1c",
app_name="python_module_1",
instance_port=9090,
data_center_name="Amazon")
You can specify the protocol, basic authentication and context path of your eureka server separatly rather than setting it at the URL.
import py_eureka_client.eureka_client as eureka_client
eureka_client.init(eureka_domain="mydomaintest.netflix.net",
region="us-east-1",
zone="us-east-1c",
eureka_protocol="https",
eureka_basic_auth_user="keijack",
eureka_basic_auth_password="kjauthpass",
eureka_context="/eureka/v2",
app_name="python_module_1",
instance_port=9090,
or
import py_eureka_client.eureka_client as eureka_client
eureka_client.init(eureka_server="your-eureka-server-peer1,your-eureka-server-peer2",
eureka_protocol="https",
eureka_basic_auth_user="keijack",
eureka_basic_auth_password="kjauthpass",
eureka_context="/eureka/v2",
app_name="python_module_1",
instance_port=9090)
About the instance IP
and hostname
:
If you are using a Amazon
data center, py-eureka-client
will try to use local-ipv4
and local-hostname
get from Amazon metadata service. In other cases, py-eureka-client
will use the first non-loopback ip address and hostname from your net interface.
You can also specify both these tow field or just one of them explicitly:
eureka_client.init(eureka_server="your-eureka-server-peer1,your-eureka-server-peer2",
eureka_protocol="https",
eureka_basic_auth_user="keijack",
eureka_basic_auth_password="kjauthpass",
eureka_context="/eureka/v2",
app_name="python_module_1",
instance_ip="192.168.10.168",
instance_host="my-py-component.mydomian.com",
instance_port=9090)
In some case you might have more than one interfaces attached, for example, you are running your application in a docker-container. In this case you can specify a network via instance_ip_network
to be used to get the container's ip and host. You can use:
eureka_client.init(eureka_server="your-eureka-server-peer1,your-eureka-server-peer2",
eureka_protocol="https",
eureka_basic_auth_user="keijack",
eureka_basic_auth_password="kjauthpass",
eureka_context="/eureka/v2",
app_name="python_module_1",
instance_ip_network="192.168.10.0/24",
instance_port=9090)
If you want to get the ip only and sepecify the host by yourself, try:
import py_eureka_client.netint_utils as netint_utils
# you can get the ip only
ip = netint_utils.get_first_non_loopback_ip("192.168.10.0/24")
host = "my-py-component.mydomian.com"
eureka_client.init(eureka_server="your-eureka-server-peer1,your-eureka-server-peer2",
eureka_protocol="https",
eureka_basic_auth_user="keijack",
eureka_basic_auth_password="kjauthpass",
eureka_context="/eureka/v2",
app_name="python_module_1",
instance_ip=ip,
instance_host=host,
instance_port=9090)
You can specify a callback function when initializing the eureka client, when errors occur in register
, discover
or status update
phase, the callback function will be called to inform you. The callback function will be called only when all the eureka server url are all tried and fails.
The callback function should accept 2 arguments. which are the error type and the exception itself. please check:
def on_err(err_type: str, err: Exception):
if err_type in (eureka_client.ERROR_REGISTER, eureka_client.ERROR_DISCOVER):
eureka_client.stop()
else:
print(f"{err_type}::{err}")
your_rest_server_port = 9090
eureka_client.init(eureka_server="http://your-eureka-server-peer1,http://your-eureka-server-peer2",
app_name="python_module_1",
instance_port=your_rest_server_port,
on_error=on_err)
After init
the eureka client, this is the most simplist way to do service:
import py_eureka_client.eureka_client as eureka_client
try:
res = eureka_client.do_service("OTHER-SERVICE-NAME", "/service/context/path")
print("result of other service" + res)
except urllib.request.HTTPError as e:
# If all nodes are down, a `HTTPError` will raise.
print(e)
do_service
function also recieve a return_type
keyword parameter, which when json
was passed, the result will be a dict
type object whereas response_object
is pass, the original HTTPResponse object will be return. Please read the relative document for more information.
You can also use its async
version:
import py_eureka_client.eureka_client as eureka_client
res = await eureka_client.do_service_async("OTHER-SERVICE-NAME", "/service/context/path")
do_service method will automatically try other nodes when one node return a HTTP error, until one success or all nodes being tried.
If you want to handle all the services' calling, you can use walk_nodes
function:
import py_eureka_client.eureka_client as eureka_client
# you can define this function with `async def`
def walk_using_your_own_urllib(url):
print(url)
"""
# Connect to url and read result, then return it.
# The result you return here will be returned to the `eureka_client.walk_nodes` function
# If you want find this node is down, you can raise a `urllib.request.HTTPError`(urllib2.HTTPError in python2)
# Then the `eureka_client.walk_nodes` will try to find another node to do the service.
"""
# result is the result that you return in walk_using_your_own_urllib function
try:
res = eureka_client.walk_nodes("OTHER-SERVICE-NAME", "/service/context/path", walker=walk_using_your_own_urllib)
print(res)
except urllib.request.HTTPError as e:
# If all nodes are down, a `HTTPError` will raise.
print(e)
A async
version is also provied:
import py_eureka_client.eureka_client as eureka_client
def walk_using_your_own_urllib(url):
print(url)
"""
# Connect to url and read result, then return it.
# The result you return here will be returned to the `eureka_client.walk_nodes` function
# If provided node is down, you can raise a `urllib.request.HTTPError`(urllib2.HTTPError in python2)
# Then the `eureka_client.walk_nodes` will try to find another node to do the service.
"""
res = await eureka_client.walk_nodes_async("OTHER-SERVICE-NAME", "/service/context/path",
walker=walk_using_your_own_urllib)
There are several HA strategies when using discovery client. They are:
In your init
function, you can specify one of the above strategies:
import py_eureka_client.eureka_client as eureka_client
# General init method
eureka_client.init(eureka_server="http://your-eureka-server-peer1,http://your-eureka-server-peer2",
app_name="your_app_name",
instance_port=your_rest_server_port,
ha_strategy=eureka_client.HA_STRATEGY_STICK)
If the build-in stratergies do not satify you, you can load all the registry by following code:
import py_eureka_client.eureka_client as eureka_client
client = eureka_client.get_client()
app = client.applications.get_application("OTHER-SERVICE-NAME")
up_instances = app.up_instances
up_instances_same_zone = app.up_instances_in_zone(client.zone)
up_instances_other_zone = app.up_instances_not_in_zone(client.zone)
inst = up_instances[0]
# ... construct your url and do the service call
You can use other http client to connect to eureka server and other service rather than the build-in urlopen method. It should be useful if you use https connections via self-signed cetificates.
From 0.11.0
, the methods of the http_client.HttpClient
are defined async
, you can now use some async http libs like aiohttp
To do this, you should:
py_eureka_client.http_client.HttpResponse
, for the reason of the py_eureka_client.http_client.HttpResponse
class wraps the http.client.HTTPResponse
which may not return by the third http libs. HttpClient
class in py_eureka_client.http_client
.urlopen
method in your class. this method must return an subclass of py_eureka_client.http_client.HttpResponse
, which is a wrapper class that hold to properties called raw_response
and body_text
. py_eureka_client.http_client
by py_eureka_client.set_http_client
import py_eureka_client.http_client as http_client
# 1. A class inherited `py_eureka_client.http_client.HttpResonse`
class MyHttpResponse(http_client.HttpResponse):
def __init__(self, raw_response):
"""
" This raw response will return when you pass `response_object` in the `do_service` function.
"""
self.raw_response = raw_response
@property
def body_text(self):
txt = ""
"""
" Read the body text from `self.raw_response`
"""
return txt
# 2. A class inherited `py_eureka_client.http_client.HttpClient`.
class MyHttpClient(http_client.HttpClient):
# 3. Rewrite the `urlopen` method in your class.
# If you want to raise an exception, please make sure that the exception is an `http_client.HTTPError` or `http_client.URLError`.
async def urlopen(self, request: Union[str, http_client.HttpRequest] = None,
data: bytes = None, timeout: float = None) -> http_client.HttpResponse:
res = await your_own_http_client_lib.do_the_visit(request, data, timeout)
return MyHttpResponse(res)
# You can parse your response object here, and set the body_text to http_client.HttpResponse, then you may ignore the http_client.HttpResponse inheritance.
# body_txt = parse_res_body(res)
# http_res = http_client.HttpResponse()
# http_res.raw_response = res
# http_res.body_text = body_text
# return http_res
# 4. Set your class to `py_eureka_client.http_client`.
http_client.set_http_client(MyHttpClient())
The default logger is try to write logs to the screen, you can specify the logger handler to write it to a file.
import py_eureka_client.logger as logger
import logging
_formatter = logging.Formatter(fmt='[%(asctime)s]-[%(name)s]-%(levelname)-4s: %(message)s')
_handler = logging.TimedRotatingFileHandler("/var/log/py-eureka-client.log", when="midnight", backupCount=7)
_handler.setFormatter(_formatter)
_handler.setLevel("INFO")
logger.set_handler(_handler)
If you want to add a handler rather than replace the inner one, you can use:
logger.add_handler(_handler)
If you want to change the logger level:
logger.set_level("DEBUG")
This logger will first save all the log record to a global queue, and then output them in a background thread, so it is very suitable for getting several logger with a same handler, especialy the TimedRotatingFileHandler
which may slice the log files not quite well in a mutiple thread environment.
This component should support deploying in Amazone EC2, it should automatically load metadata from Amazon metadata service. All the metadata keys come from com.netflix.appinfo.AmazonInfo
in Netflix's java client. BUT for the reason that I have no amazon environment to test, it may not work. If errors occurs, please submit an issue and provide some detail logs, I will try to fix it as far as I can. If it works, a reply in this issue is wellcomed.
You can find more information in the project comments.