Update inveniostore to remove httplib and use the power of module requests.

modules/invenio_tools/inveniostore.py

 """ invenio_tools.inveniostore
 
 """
-import http.client
 import json
 import re
 import requests
 import time
 
 from .exception import CdsException
+from requests.adapters import HTTPAdapter
+from requests.exceptions import ConnectionError, HTTPError
 
 
 CDS_SEARCH_KEYS = ("req", "cc", "c", "ec", "p", "f", "rg", "sf", "so", "sp",
@@ -47,10 +48,13 @@ class InvenioStore(object):
         """
         self._host = host
         self._url = None
-        self._try = 0
 
         # start a session, a persistent connection with the server
-        self._session = requests.Session()
+        # let the session handle the number of retry
+        session = requests.Session()
+        session.mount(f"http://{host}", HTTPAdapter(max_retries=3))
+
+        self._session = session
 
     def __del__(self):
         # close the session
@@ -64,30 +68,25 @@ class InvenioStore(object):
             params (dict): parameters to be send with the URL
 
         Returns:
-            unicode: the HTTP response
+            str: the HTTP response
 
         Raises:
-            CdsException: when the server return an HTTP error
-                five consecutive time.
+            CdsException:
+                when the server returns connection or HTTP error.
 
         """
         self._url = url
-        self._try += 1
 
-        r = self._session.get(url, params=params)
-        code = r.status_code
-        data = r.content
+        try:
+            r = self._session.get(url, params=params)
 
-        # the server is busy or return error wait one minute an retry.
-        # the number of trial is limited to 5
-        if code == http.client.SERVICE_UNAVAILABLE or code != http.client.OK:
-            if self._try == 5:
-                raise CdsException("%s %s" % (MSG_HTTP_ERROR, code))
+        except ConnectionError as ce:
+            raise CdsException(str(ce))
 
-            time.sleep(60)
-            self.interogate(url)
+        except HTTPError as he:
+            raise CdsException(str(he))
 
-        return data
+        return r.text
 
     def get_ids(self, **kwargs):
         """Return a list of *record id* matching search criteria.
@@ -162,14 +161,13 @@ class InvenioStore(object):
         # Therefore to recuperate the complete list of ids we have to get them
         # by block of 200. The later is the maximum value allowed by cds.
         # We use the parameter rg and jrec to steer the scan.
-        # Thy have no effect on inspirehep.net.
+        # They have no effect on inspirehep.net.
 
         kwargs["of"] = "id"
         kwargs["rg"] = N_IDS
         kwargs["jrec"] = -N_IDS
 
         while scan:
-            self._try = 0
             kwargs["jrec"] += N_IDS
 
             url = "http://%s/search" % self._host