repo.py

"""
This module contains a class that allows us to interact with the 
repository of interest.

"""
import tempfile
import shutil
import subprocess
import os

class Repo(object):
    """
    Interact with a repository: attributes, extract a copy, cleanup.
    
    This could maybe be re-written as a context manger so the cleanup happens
    automatically.
    
    """
    
    def __init__(self, name, url, rtype="git"):
        """
        name - Name of the project
        url - url of the project
        rtype - type of the repository. This will mostly be git.
            
        """
        self.name = name
        self.url = url
        self.rtype = rtype
        
        self.local_resources = []
        self.extracted = False
        self.file_list = []
        self.tmpdir = None
            
        
    def extract_local_copy(self):
        """Extract a local copy of the repository"""
        
        self.tmpdir = tempfile.mkdtemp()
        self.local_resources.append(self.tmpdir)
        if self.rtype is "git":
            extract_cmd = "git clone {url} {odir}".format(url=self.url,
                                                          odir=self.tmpdir)
        else:
            # We could implement SVN here, a quick svn export would do.
            raise NotImplemented
            
        try:
            subprocess.check_call(extract_cmd.split())
        except subprocess.CalledProcessError:
            raise IOError("Unable to extract a local copy of repository")
        else:
            self.extracted = True
    
    def has(self, filename):
        """
        Does the repository have a file matching a particular name? If it does
        then return the filename, otherwise return False.
        
        """
        if not self.extracted:
            self.extract_local_copy()
            
        if not self.file_list:
            self._get_filelist()
            
        for f in self.file_list:
            if filename in f:
                return f
                
        return False
            
    def _get_filelist(self):
        """Just get a list of the files in the repo."""
        
        if not self.extracted:
            self.extract_local_copy()        
        
        for root, dirs, files in os.walk(self.tmpdir, topdown=True):
            for name in files:
                self.file_list.append(os.path.join(root, name))
        
            
    def cleanup(self):
        """Remove any local resources"""
        
        for resource in self.local_resources:
            try:
                shutil.rmtree(resource)
            except:
                print "Unable to remove: {}".format(resource)