Implement MySQL check script for Docker

Story: 2001694
Task: 23321

Change-Id: I103c864832cd85ec528080cb7d49393c09127c60
This commit is contained in:
Dobroslaw Zybort 2018-07-25 14:05:35 +02:00 committed by Witold Bedyk
parent 1cce6824ed
commit dcea427a62
2 changed files with 83 additions and 9 deletions

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@ -5,7 +5,7 @@
# https://github.com/pyca/cryptography/pull/4270
FROM python:3.5.5-alpine3.7
COPY wait_for.sh kafka_wait_for_topics.py /
COPY wait_for.sh kafka_wait_for_topics.py mysql_check.py /
COPY ashrc /root/.ashrc
ENV \
@ -23,7 +23,7 @@ LABEL org.opencontainers.image.revision="$BASE_GIT_COMMIT"
LABEL org.opencontainers.image.licenses="Apache-2.0"
RUN \
chmod +x /wait_for.sh /kafka_wait_for_topics.py && \
chmod +x /wait_for.sh /kafka_wait_for_topics.py /mysql_check.py && \
apk add --no-cache \
su-exec=0.2-r0 \
tini=0.16.1-r0 \

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@ -19,15 +19,34 @@
It's checking if requested database already exists.
For using this script you need to set some environment variables:
* `MYSQL_HOST` for connection string to MySQL.
Example: `mysql`, `192.168.10.6`.
Default: `mysql`.
* `MYSQL_PORT` for connection string to MySQL port.
Default: `3306`.
* `MYSQL_USER` for user that is cappable to connect to MySQL.
Default: `monapi`.
* `MYSQL_PASSWORD` for user password.
Default: `password`.
* `MYSQL_DB` for database that you need to have before starting service.
Default: `mon`.
After making sure that this environment variables are set you can simply
execute this script in the following way:
`python3 mysql_check.py && ./start_service.sh`
`python3 mysql_check.py || exit 1`
Additional environment variables available are:
* `LOG_LEVEL` - default to `INFO`
* `MYSQL_WAIT_RETRIES` - number of retries, default to `24`
* `MYSQL_WAIT_INTERVAL` - in seconds, default to `5`
"""
import logging
import os
import sys
import time
import pymysql
@ -42,7 +61,7 @@ logging.basicConfig(level=LOG_LEVEL)
logger = logging.getLogger(__name__)
MYSQL_HOST = os.environ.get('MYSQL_HOST', 'mysql')
MYSQL_PORT = os.environ.get('MYSQL_HOST', 3306)
MYSQL_PORT = os.environ.get('MYSQL_PORT', 3306)
MYSQL_USER = os.environ.get('MYSQL_USER', 'monapi')
MYSQL_PASSWORD = os.environ.get('MYSQL_PASSWORD', 'password')
MYSQL_DB = os.environ.get('MYSQL_DB', 'mon')
@ -50,9 +69,64 @@ MYSQL_DB = os.environ.get('MYSQL_DB', 'mon')
MYSQL_WAIT_RETRIES = int(os.environ.get('MYSQL_WAIT_RETRIES', '24'))
MYSQL_WAIT_INTERVAL = int(os.environ.get('MYSQL_WAIT_INTERVAL', '5'))
# TODO(Dobroslaw): All checks and retry.
db = pymysql.connect(
host=MYSQL_HOST, port=MYSQL_PORT,
user=MYSQL_USER, passwd=MYSQL_PASSWORD,
db=MYSQL_DB
)
def retry(retries=MYSQL_WAIT_RETRIES, delay=MYSQL_WAIT_INTERVAL,
check_exceptions=()):
"""Retry decorator."""
def decorator(func):
"""Decorator."""
def f_retry(*args, **kwargs):
"""Retry running function on exception after delay."""
for i in range(1, retries + 1):
try:
return func(*args, **kwargs)
# pylint: disable=W0703
# We want to catch all exceptions here to retry.
except check_exceptions + (Exception,) as exc:
if i < retries:
logger.info('Connection attempt %d of %d failed',
i, retries)
if isinstance(exc, check_exceptions):
logger.debug('Caught known exception, retrying...',
exc_info=True)
else:
logger.warn(
'Caught unknown exception, retrying...',
exc_info=True)
else:
logger.exception('Failed after %d attempts', retries)
raise
# No exception so wait before retrying
time.sleep(delay)
return f_retry
return decorator
@retry(check_exceptions=(pymysql.err.OperationalError,))
def connect_mysql(host, port, user, password, database):
"""Connect to MySQL with retries."""
return pymysql.connect(
host=host, port=port,
user=user, passwd=password,
db=database
)
def main():
"""Start main part of the wait script."""
logger.info('Waiting for database: `%s`', MYSQL_DB)
connect_mysql(
host=MYSQL_HOST, port=MYSQL_PORT,
user=MYSQL_USER, password=MYSQL_PASSWORD,
database=MYSQL_DB
)
logger.info('Database `%s` found', MYSQL_DB)
if __name__ == '__main__':
main()