cass_migrate

Python script to perform migrations for cql scripts

Requirements

1. java version >= 8
2. python >=2.7 or >= 3.6
3. cassandra db
4. cassandra-driver (pip install cassandra-driver)

Procedure

Assuming that we have cassandra db setup in our system(windows system)

1. navigate to ur cassandra db config folder. In my case its

   C:\Users\USER\Downloads\apache-cassandra-3.11.4\conf

   change the value of authorizer to AllowAllAuthorizer in cassandra.yaml

   i.e authorizer: AllowAllAuthorizer

2. navigate to the bin folder via cmd. In my case its

   C:\Users\USER\Downloads\apache-cassandra-3.11.4\bin

   then do cassandra

3. open another terminal in the same bin location and do cqlsh

   for dooin so u need to have python 2.7

   cassandra dbs command line interface can only be accessed if u hv py2.7

4. if uhv successfully entered cassandras commandline

   lets create a super user but first get out of cqlsh by hittin exit in cmd

   for creating super user do the following

   1. cqlsh -u cassandra -p cassandra
   
   2. CREATE ROLE was_up_bro with SUPERUSER = true AND LOGIN = true and PASSWORD = 'was_up';
      
   3. EXIT;
   

5. now lets login with the newly created user and

   create a new keyspace(DataBase)

   1. cqlsh -u was_up_bro -p was_up
   
   2. CREATE KEYSPACE IF NOT EXISTS rim_jim_cutie_pie WITH replication = { 'class': 'SimpleStrategy', 'replication_factor': '3' }
   

6. now i guess if everythin went well, we r good to perform migrations

7. so, lets perform a migration

   if u can see we have sm set of scripts in scripts path

   lets use a set from those set of scripts

   navigate to the folder where cass_migrates manage.py is located

   in my case D:\vishnu personal\git_kraken_repositories\cass_migrate

   and execute the followin cmd

   python manage.py host user_name password port key_space application_name env_name mode cql_files_path
   

   eg :

   for creating a migration ie. up set mode as up

   python manage.py 127.0.0.1 was_up_bro was_up 9042 rim_jim_cutie_pie app_1 dev up test_1 
   

   for goin back to a previous version i.e down set mode as down

   python manage.py 127.0.0.1 was_up_bro was_up 9042 rim_jim_cutie_pie app_1 dev down
   

   for migrating to a desired version specify the version number after the mode

   python manage.py 127.0.0.1 was_up_bro was_up 9042 rim_jim_cutie_pie app_1 dev down 1
   

   assuming we have 3 migrations and we want to migrate to version 1 the above down command works

   down can only be performed if there is a successful up that has been performed on the specified keyspace

if smthin is wrong check the logs to see what went wrong

if ya feel like smthis is fishy create another keyspace and use it