Migrate with different user account?

[Mark Thomas]

In my environment, the application logins do not have the ability to
alter the schema to create tables, etc. There is a separate schema
owner account with that capability. So I cannot run "rake migrate"
using the database.yml configuration. Is there a way to run migrations
with a different account?

Thanks,
- Mark.

[Greg Donald]

There isn't any magical way to do more than the permissions you have allow you to do, if that's what you're asking. If you have a different db user account that has sufficient permissions, then just plug it into the database.yml file.

--
Greg Donald
Cyberfusion Consulting
http://cyberfusionconsulting.com/

[Mark Thomas]

Let me be more specific. My rails app is not allowed to use the schema
owner account, so I cannot just put it in the database.yml file. In
addition, I cannot leave the password for that account on the
filesystem. So even if there was a way to select a different
database.yml file for the migrations only, I cannot do that. (Although
I'd still be interested to know if there's a way to select a different
database.yml on the fly).

What would be ideal: a front end to rake db:migrate that asks me for
the username/password to the account, and overrides the database.yml
entries for them. Is there a way to do this via a new rake task? Or
maybe it would be easier to modify the existing db:migrate task?

[Matthew Rudy]

how about this solution;

database.yml
============

<%
def as_db_admin?
defined?(AS_DB_ADMIN) && AS_DB_ADMIN == "true"
end
%>
production:
adapter: mysql
database: databasename
host: localhost
username: <%= as_db_admin? ? "root" : "normal" %>
password: <%= as_db_admin? ? "root" : "normal" %>

============

"rake db:migrate AS_DB_ADMIN=true"

I belive that'll set the global constant AS_DB_ADMIN,
and hence do what you want.

Otherwise it sets ENV["AS_DB_ADMIN"]
but I think it actually sets the constant directly.

Give it a try.
--
Posted via http://www.ruby-forum.com/.

[Mark Thomas]

Huh? YAML files are run through ERB? I wouldn't have thought this to
be the case. Nevertheless, I'll try it.

[Matthew Rudy]

Mark Thomas wrote:
> Huh? YAML files are run through ERB? I wouldn't have thought this to
> be the case. Nevertheless, I'll try it.

yeah.
it's not obvious, until you look at the code.

I use it all the time, so I can do host specific databases
(namely I have 3 different environments I want to run the tests on, some
of them have the database running on localhost, but the others have
dedicated db servers with different names)

it works proper fine.

<%
def sharon_or_localhost
if ["punky", "munky"].include? Socket.gethostname
return "sharon"
else
return "localhost"
end
end
%>

test:
adapter: mysql
database: testdb
username: test_user
password: th1si5aTESt
host: <%= sharon_or_localhost %>

[Matthew Rudy]

and here's the code out of the rails initializer

# Loads and returns the contents of the #database_configuration_file.
The
# contents of the file are processed via ERB before being sent through
# YAML::load.
def database_configuration
YAML::load(ERB.new(IO.read(database_configuration_file)).result)
end

see railties/lib/initializer.rb -- don't know which line.

[Mark Thomas]

On Sep 5, 9:43 am, Mark Thomas <r...@thomaszone.com> wrote:
> Huh? YAML files are run through ERB? I wouldn't have thought this to
> be the case. Nevertheless, I'll try it.

Nope, it is as I thought--you can't put ERB into database.yml.

I'm going down the path of trying a custom rake task, but I have no
idea where database.yml exists as a variable after it has been loaded
by Rails. Does anyone know?

[Matthew Rudy]

Mark Thomas wrote:
> On Sep 5, 9:43 am, Mark Thomas <r...@thomaszone.com> wrote:
>> Huh? YAML files are run through ERB? I wouldn't have thought this to
>> be the case. Nevertheless, I'll try it.
>
> Nope, it is as I thought--you can't put ERB into database.yml.

hmm...
well I haven't bothered to go any further back than revision 2115,
but ERB parsing of database.yml has been in rails trunk since at least
September 2005, maybe before then even.

[Matthew Rudy]

Matthew Rudy wrote:
> Mark Thomas wrote:
>> On Sep 5, 9:43 am, Mark Thomas <r...@thomaszone.com> wrote:
>>> Huh? YAML files are run through ERB? I wouldn't have thought this to
>>> be the case. Nevertheless, I'll try it.
>>
>> Nope, it is as I thought--you can't put ERB into database.yml.

and equally;
ActiveRecord::Base.configurations is the hash of the database
connections.

[Matthew Rudy]

Matthew Rudy wrote:
> Matthew Rudy wrote:
>> Mark Thomas wrote:
>>> On Sep 5, 9:43 am, Mark Thomas <r...@thomaszone.com> wrote:
>>>> Huh? YAML files are run through ERB? I wouldn't have thought this to
>>>> be the case. Nevertheless, I'll try it.
>>>
>>> Nope, it is as I thought--you can't put ERB into database.yml.
>
> and equally;
> ActiveRecord::Base.configurations is the hash of the database
> connections.

and I think this rake task will do what you want also

================
/lib/tasks/migrate_as_root.rake
================

ROOT_USER_PASS_HASH = {"username" => "root", "password" => "rootpass"}

desc "run your migration as db root"
task "db:migrate_as_root" do
original_config = ActiveRecord::Base.configurations[RAILS_ENV ||
"development"]
config = original_config.merge(ROOT_USER_PASS_HASH)
ActiveRecord::Base.establish_connection(config)

Rake::Task["db:migrate"].invoke
end

[Mark Thomas]

> well I haven't bothered to go any further back than revision 2115,
> but ERB parsing of database.yml has been in rails trunk since at least
> September 2005, maybe before then even.

Well then I apologize. My quick test didn't work and I guess I jumped
to the conclusion.

> > and equally;
> > ActiveRecord::Base.configurations is the hash of the database
> > connections.

Thanks!

> and I think this rake task will do what you want also
>
> ================
> /lib/tasks/migrate_as_root.rake
> ================
>
> ROOT_USER_PASS_HASH = {"username" => "root", "password" => "rootpass"}
>
> desc "run your migration as db root"
> task "db:migrate_as_root" do
> original_config = ActiveRecord::Base.configurations[RAILS_ENV ||
> "development"]
> config = original_config.merge(ROOT_USER_PASS_HASH)
> ActiveRecord::Base.establish_connection(config)
>
> Rake::Task["db:migrate"].invoke
> end

Yes! This is very close to what I need. I'll take it from here. Thank
you very much!

- Mark.

[Matthew Rudy]

Mark Thomas wrote:
>
>
> Yes! This is very close to what I need. I'll take it from here. Thank
> you very much!
>
> - Mark.

Yeah, no wuzz...
I don't like being wrong.

Take it easy....

btw, do you happen to know of Mark Thomas the english
comedian/activist... he's pretty darn cool.

[Anirudhan J.]

Mark Thomas wrote in post #550700:

>> well I haven't bothered to go any further back than revision 2115,
>> but ERB parsing of database.yml has been in rails trunk since at least
>> September 2005, maybe before then even.
>
> Well then I apologize. My quick test didn't work and I guess I jumped
> to the conclusion.
>
>> > and equally;
>> > ActiveRecord::Base.configurations is the hash of the database
>> > connections.
>
> Thanks!
>

>> original_config = ActiveRecord::Base.configurations[RAILS_ENV ||
>> "development"]
>> config = original_config.merge(ROOT_USER_PASS_HASH)
>> ActiveRecord::Base.establish_connection(config)
>>
>> Rake::Task["db:migrate"].invoke
>> end
>
> Yes! This is very close to what I need. I'll take it from here. Thank
> you very much!
>
> - Mark.

Were you able to do this successfully? And how did you handle
capistrano tasks?