requirements.txt should not list psycopg2

[Albert White]

requirements.txt currently lists psycopg2 and so we attempt to install it when install_rally.sh is ran.

Postgres however is not a requirement to run rally as a user may choose mysql or sqlite, and if the user does not have postgres installed this will fail ("Error: pg_config executable not found.") and abort the install.

install_rally.sh already takes a database parameter and will pip install psycopg2 if postgres was selected. However this does not appear to try and install it in the virtualenv that may be created.

Since install_rally.sh is the documented way to install rally I suggest resolving this by:
- remove the psycopg2 line from requirements.txt
- have install_db_connector in install_rally.sh append psycopg2 to requirements.txt if postgres was selected.

[Albert White (albertw)]

Adding in from irc discussion on this one

andreykurilin albertw1: about https://bugs.launchpad.net/rally/+bug/1469104 . At first, install_rally.sh should install postgres, mysql related packages based on DBTYPE variable and than, we will be able to remove psycopg from our requirements

andreykurilin albertw1, also, I suggest to have new file: db-requirements.txt with list of all db-related stuff, so users will be able to find additional requirement for installation rally without installation script

albertw1 thanks andreykurilin . install_rally already does the pip install, but for linux distros it just tries to install the db packages also, that should probably be dependent on $DBTYPE. Should anything else depend on or source the proposed db-requirements.txt file or would it just be there to help users?

andreykurilin albertw1: db-requirements should used only for helping users to find required python package. Maybe, the better way to store such information is https://github.com/openstack/rally/blob/master/doc/source/tutorial/step_0_installation.rst

albertw1 great. Thanks for the help

[Boris Pavlovic (boris-42)]

Fixed here:
https://review.openstack.org/#/c/190931/