helm-projectile: how to search in multiple git repo

Question

I use helm-projectilein Emacs to search code in my codebase.

The structure of my codebase looks like this:

/rootdir
    /project1
        /.git
        /code
        /doc
    /project2
        /.git
        /code
        /doc
    /project3
        /...

I have three git repo and I only want to search in their code sub-directory. More importantly, when I do hlem-projectile-ack in project1. I want the search results to include the result from project2/code and project3/code.

By the default, helm-projectile only searches in the current git repo. How can I change the default search root to be /rootdir and also effectively ignore everything under /doc folders?

Answer 1

This can be solved by adding a .projectile under /rootdir

+project1/code
+project2/code
+project3

Reference: Projects in Projectile. By the way, the documentation says that contents of .projectile are ignored when the alien indexing method is used. I am using alien method and adding a .projecctile works for me.