Multiple Ecto Repos

A quick intro to using multiple repos in an Elixir project.

Transcript

1. Multiple Ecto Repos + Edgardo Roman 5.29.19
2. Intro • Software Developer at Transport Tech LLC. • Elixir, AngularJS
3. Why Multiple Repos? • Provides flexibility for structuring projects • Allows for separate data solutions:
 - multiple databases
 - different provider (i.e. Postgres, Mongo, etc) • Set privileges specifically for each repos depending on security needs (DDL vs. DML)
4. Roles • Can be assigned to a single database user or a group of users • Can own database objects (tables, functions, etc) • Can assign privileges on those objects to other roles
5. Grant / Revoke Privileges • Adds / removes privileges to or from a database object or a role • Privileges are added to any existing privileges, including:
 - Privileges for that role
 - Privileges for any other roles the user is a member of
 - AND privileges granted to Public
6. Basic Setup • Entries for each repo in environmental config file
 - if adding more than one repo in ecto_repos, 
 then the -r flag must be used when running mix tasks • Add repos to supervisor of Application module • Create file for each repo • Write migration to set privileges for additional repos.
7. Resources https://www.postgresql.org/docs/current/sql-grant.html https://www.postgresql.org/docs/10/sql-alterdefaultprivileges.html https://marcyes.com/2016/0922-messing-with-postgresql-users-and-permissions/ https://www.2ndquadrant.com/en/blog/auditing-users-and-roles-in-postgresql/ https://dba.stackexchange.com/questions/33943/granting-access-to-all-tables-for-a-user https://dba.stackexchange.com/questions/35316/why-is-a-new-user-allowed-to-create-a-table https://dba.stackexchange.com/questions/207740/postgresql-grant-privileges-as-superuser?rq=1 https://medium.com/@McElaney/using-two-repos-in-phoenix-eb4608f5f78d