sonus21

/*
 * Copyright (c) 2023 Sonu Kumar, sonunitw12@gmail.com
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * You may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software

sonus21

#Adapted from https://djangosnippets.org/snippets/2619/

@register.tag(name='counter')
def do_counter(parser, token):
    """
    Counter tag. Can be used to output and increment a counter.

    Usage:
    - {% counter %} to output and post-increment the counter variable
    - {% counter reset %} to reset the counter variable to 1

sonus21

import threading

threadLocal = threading.local()


def get_current_db_name():
    return getattr(threadLocal, "DB", None)


def set_db_for_router(db):

sonus21

INSTALLED_APPS = [
    # ...
    "CoreApp"
    # ...
]



MIDDLEWARE = [

sonus21

from functools import wraps

from .utils import db_from_the_request
from .db_router import set_db_for_router, clear_db_for_router


class DatabaseMiddleware(object):
    """
    DatabaseMiddleware sets the db in the thread local context and used
    across multiple calls to handle the DB calls.

sonus21

from .constants import SECONDARY, PRIMARY
from CoreApp.middlewares import db_wrapper


@db_wrapper(PRIMARY)
def reserve_driver(request):
    # logic goes here
    pass

sonus21

/**
 * A Database annotation that should be used at controller,worker,consumer,methods or classes
 * to route the database traffic to appropriate node.
 */
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.METHOD})
public @interface Database {
    String value() default "";
}

sonus21

public class DatabaseContext {
    private static final ThreadLocal<String> databaseName = new ThreadLocal<>();

    public static void set(String name) {
        databaseName.set(name);
    }

    public static void clear() {
        databaseName.remove();
    }

sonus21

public class DatabaseRouter extends AbstractRoutingDataSource {
    @Override
    protected Object determineCurrentLookupKey() {
        return DatabaseContext.get();
    }
}

sonus21

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = {"com.github.sonus21.readwrite.repositories"})
@EntityScan(basePackages = "com.github.sonus21.readwrite.models.entities")
public class SqlDatabaseConfiguration {

    private final DataSourceSecondaryConfig dataSourceSecondaryConfig;
    private final DataSourcePrimaryConfig dataSourcePrimaryConfig;

    @Autowired