Tiny Retry

What is TinyRetry?

tinyretry is a python module that provides failure retry encapsulation for the target function

Programming Language

• python 2.7
• python 3.7

Install

pip install tinyretry 

Quick Start

use python decorators syntax to wrap the call target

Case 1: retry until the return code equals to the special value

When we call the function and hope to get the special return code, then we can use RetryUntilForJson or RetryUntilForBool

from tinyretry import RetryUntilForJson

@RetryUntilForJson(retry_code_key='errno', expected_err_code=0, max_retry_num = 10, retry_interval_sec = 0.1)
def DoHttpRequest1():
    errno = random.randint(0,2)
    errmsg_arr = ['ok', 'err-timeout', 'err-req-limit']
    return {
        "errno": errno,
        "errmsg": errmsg_arr[errno]
    }

class Test_TinyRetry(unittest.TestCase):
    def test_RetryUntilForJson(self):
        for i in range(5):
            res = DoHttpRequest1()
            self.assertEqual(res["errno"], 0)

Then you can get the return value from the function DoHttpRequest1() which must be successful, the call log like this:

bogon:tinyretry jamesqin$ python tinyretry_test.py
2020-02-14 14:03:14,754 - root - INFO - call RetryUntilForJson(DoHttpRequest)(...)
2020-02-14 14:03:14,754 - root - INFO -     Get expected error code 0
2020-02-14 14:03:14,754 - root - INFO - call RetryUntilForJson(DoHttpRequest)(...)
2020-02-14 14:03:14,754 - root - INFO -     Error code 2 was found, retry 1
2020-02-14 14:03:14,859 - root - INFO -     Get expected error code 0
2020-02-14 14:03:14,860 - root - INFO - call RetryUntilForJson(DoHttpRequest)(...)
2020-02-14 14:03:14,860 - root - INFO -     Error code 1 was found, retry 1
2020-02-14 14:03:14,964 - root - INFO -     Error code 1 was found, retry 2
2020-02-14 14:03:15,070 - root - INFO -     Error code 1 was found, retry 3
2020-02-14 14:03:15,172 - root - INFO -     Error code 2 was found, retry 4
2020-02-14 14:03:15,278 - root - INFO -     Get expected error code 0
2020-02-14 14:03:15,278 - root - INFO - call RetryUntilForJson(DoHttpRequest)(...)
2020-02-14 14:03:15,278 - root - INFO -     Error code 2 was found, retry 1
2020-02-14 14:03:15,381 - root - INFO -     Error code 1 was found, retry 2
2020-02-14 14:03:15,482 - root - INFO -     Error code 1 was found, retry 3
2020-02-14 14:03:15,586 - root - INFO -     Error code 1 was found, retry 4
2020-02-14 14:03:15,692 - root - INFO -     Error code 2 was found, retry 5
2020-02-14 14:03:15,794 - root - INFO -     Get expected error code 0
2020-02-14 14:03:15,794 - root - INFO - call RetryUntilForJson(DoHttpRequest)(...)
2020-02-14 14:03:15,794 - root - INFO -     Get expected error code 0
.
----------------------------------------------------------------------
Ran 1 test in 1.040s

OK

Case 2: while the return code equals to the special value, we will retry

When we call the function and hope to skip the special return code, then we can use RetryWhileForJson or RetryWhileForBool

from tinyretry import RetryWhileForJson

@RetryWhileForJson(retry_code_key='errno', not_expected_err_code=2, max_retry_num = 10, retry_interval_sec = 0.1)
def DoHttpRequest2():
    errno = random.randint(0,2)
    errmsg_arr = ['ok', 'err-timeout', 'err-req-limit']
    return {
        "errno": errno,
        "errmsg": errmsg_arr[errno]
    }

class Test_TinyRetry(unittest.TestCase):
    def test_RetryWhileForJson(self):
        for i in range(5):
            res = DoHttpRequest2()
            self.assertNotEqual(res["errno"], 2)

then call log look like this:

2020-02-14 14:13:30,708 - root - INFO - call RetryWhileForJson(DoHttpRequest2)(...)
2020-02-14 14:13:30,708 - root - INFO -     Error code 2 was found, retry 1
2020-02-14 14:13:30,810 - root - INFO -     Error code 2 was found, retry 2
2020-02-14 14:13:30,912 - root - INFO -     Error code 2 was found, retry 3
2020-02-14 14:13:31,013 - root - INFO -     Error code 2 was found, retry 4
2020-02-14 14:13:31,117 - root - INFO -     Error code 2 was found, retry 5
2020-02-14 14:13:31,222 - root - INFO -     Get not expected error code 1
2020-02-14 14:13:31,222 - root - INFO - call RetryWhileForJson(DoHttpRequest2)(...)
2020-02-14 14:13:31,222 - root - INFO -     Get not expected error code 0
2020-02-14 14:13:31,222 - root - INFO - call RetryWhileForJson(DoHttpRequest2)(...)
2020-02-14 14:13:31,222 - root - INFO -     Error code 2 was found, retry 1
2020-02-14 14:13:31,324 - root - INFO -     Get not expected error code 0
2020-02-14 14:13:31,324 - root - INFO - call RetryWhileForJson(DoHttpRequest2)(...)
2020-02-14 14:13:31,324 - root - INFO -     Error code 2 was found, retry 1
2020-02-14 14:13:31,426 - root - INFO -     Error code 2 was found, retry 2
2020-02-14 14:13:31,529 - root - INFO -     Get not expected error code 1
2020-02-14 14:13:31,529 - root - INFO - call RetryWhileForJson(DoHttpRequest2)(...)
2020-02-14 14:13:31,529 - root - INFO -     Get not expected error code 1

Other useful retry functions:

This package provide two scenarios of failure retries

• Until scene
  • RetryUntilForJson()
  • RetryUntilForBool()
• while scene
  • RetryWhileForJson()
  • RetryWhileForBool()