https://github.com/last9/pyhystrix
Hystrix brought to Python
https://github.com/last9/pyhystrix
circuit-breaker hystrix python
Last synced: 5 days ago
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Hystrix brought to Python
- Host: GitHub
- URL: https://github.com/last9/pyhystrix
- Owner: last9
- License: mit
- Created: 2017-11-26T15:54:09.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2022-12-07T23:56:06.000Z (over 2 years ago)
- Last Synced: 2025-03-30T09:31:33.167Z (24 days ago)
- Topics: circuit-breaker, hystrix, python
- Language: Python
- Homepage:
- Size: 23.4 KB
- Stars: 22
- Watchers: 3
- Forks: 2
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# pyhystrix
### A library to patch requests package in order to add following functionalities by default:
- Connection and Read timeouts
- Retries on connection failure
- Circuitbreaking
- Adding unique `x-request-id` in request header if not provided
**NOTE:**: 0.0.2 supports python2.7 and >= 0.0.3 supports python3 only.
Installation
------------
```sh
pip3 install pyhystrix
```
Usage
-----
Before making any request, just call `Init()`:
```python
import requests
import pyhystrix
requests.get("http://abc.xyx") // No functionalities of pyhystrix
pyhystrix.Init()
requests.get("http://abc.xyx") // pyhystrix is attached to all requests
```
Default Configurations can be changed in 2 ways:
1. Setting following env variables:
- `PHY_CONNECT_TIMEOUT` : connection timeout in sec
- `PHY_READ_TIMEOUT`: read timeout in seconds
- `PHY_MAX_RETRIES`: max number of retries for connection failure
- `PHY_CIRCUIT_FAIL_THRESHOLD`: Number of failed requests after which circuit will be open and further requests on the same url will not be allowed.
- `PHY_CIRCUIT_ALIVE_THRESHOLD`: Number of failed requests on open circuit to make it half_open (Described below)
- `PHY_CIRCUIT_DELAY`: Number of seconds after which open circuit will be half_open.
2. parameters in request itself:
- `max_tries`(int): overrides `PHY_MAX_RETRIES`, some rules related to it are follows:
- `max_tries=0`: will cause no retries, fail on first failure.
- If a positive value is passed for non `GET` requests, they will be retried too in case received status is in `status_forcelist`.
- `status_forcelist`: list of http status, retry if the returned status is one of these. default is `[500]` on `GET`.
- `timeout`: same as timeout in [requests](http://docs.python-requests.org/en/master/user/advanced/#timeouts)
- `backoff_factor`: delay in each retry will be affected by this using following formula: ```{backoff factor} * (2 ^ ({number of total retries} - 1))```. Default = `0.5`sec
More Examples
-------------
- `GET` with retry on multiple failure status codes:
```python
import requests
import pyhystrix
pyhystrix.Init()
request.get("http://abc.xyz", status_forcelist=[501, 502, 403])
```
- `put` with retry on response status = `500` or `501`
```python
request.put("http://abc.xyz", max_tries=3, status_forcelist=[500, 502])
```
**NOTE:** All type of requests will be retried in case of `ConnectionError`
Circuit Breaker States
---------------
1. **OPEN** : No requests will be allowed
2. **HALF_OPEN** : Only one request will be allowed
3. **CLOSE** : All requests will be allowed.
**NOTE** : State transitions:
`CLOSE --> OPEN --> HALF_OPEN --> CLOSE/OPEN`
### To know more about circuit breaker pattern, click [here](https://martinfowler.com/bliki/CircuitBreaker.html)