ghlister: move to swh.lister.github as per swh convention

Closes T30

swh/lister/github/__init__.py

@@ -0,0 +1 @@
+# placeholder

swh/lister/github/db_utils.py

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+# Copyright (C) 2015  Stefano Zacchiroli <zack@upsilon.cc>
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+from contextlib import contextmanager
+
+
+@contextmanager
+def session_scope(mk_session):
+    session = mk_session()
+    try:
+        yield session
+        session.commit()
+    except:
+        session.rollback()
+        raise
+    finally:
+        session.close()

swh/lister/github/lister.py

@@ -0,0 +1,161 @@
+# Copyright (C) 2015  Stefano Zacchiroli <zack@upsilon.cc>
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+# see https://developer.github.com/v3/ for GitHub API documentation
+
+import gzip
+import logging
+import os
+import re
+import requests
+import time
+
+from pprint import pformat
+from sqlalchemy import func
+
+from swh.lister.github.db_utils import session_scope
+from swh.lister.github.models import Repository
+
+
+GH_API_URL = 'https://api.github.com'
+MAX_RETRIES = 7
+MAX_SLEEP = 3600  # 1 hour
+CONN_SLEEP = 10
+
+REPO_API_URL_RE = re.compile(r'^.*/repositories\?since=(\d+)')
+
+
+def save_http_response(r, cache_dir):
+    def escape_url_path(p):
+        return p.replace('/', '__')
+
+    fname = os.path.join(cache_dir,
+                         escape_url_path(r.request.path_url) + '.gz')
+    with gzip.open(fname, 'w') as f:
+        def emit(s):
+            f.write(bytes(s, 'UTF-8'))
+        emit(pformat(r.request.path_url))
+        emit('\n#\n')
+        emit(pformat(r.status_code))
+        emit('\n#\n')
+        emit(pformat(r.headers))
+        emit('\n#\n')
+        emit(pformat(r.json()))
+
+
+def gh_api_request(path, username=None, password=None, headers={}):
+    params = {}
+    if 'Accept' not in headers:  # request version 3 of the API
+        headers['Accept'] = 'application/vnd.github.v3+json'
+    params['headers'] = headers
+    if username is not None and password is not None:
+        params['auth'] = (username, password)
+
+    retries_left = MAX_RETRIES
+    while retries_left > 0:
+        logging.debug('sending API request: %s' % path)
+        try:
+            r = requests.get(GH_API_URL + path, **params)
+        except requests.exceptions.ConnectionError:
+            # network-level connection error, try again
+            logging.warn('connection error upon %s: sleep for %d seconds' %
+                         (path, CONN_SLEEP))
+            time.sleep(CONN_SLEEP)
+            retries_left -= 1
+            continue
+
+        if r.ok:  # all went well, do not retry
+            break
+
+        # detect throttling
+        if r.status_code == 403 and \
+           int(r.headers['X-RateLimit-Remaining']) == 0:
+            delay = int(r.headers['X-RateLimit-Reset']) - time.time()
+            delay = min(delay, MAX_SLEEP)
+            logging.warn('rate limited upon %s: sleep for %d seconds' %
+                         (path, int(delay)))
+            time.sleep(delay)
+        else:  # unexpected error, abort
+            break
+
+        retries_left -= 1
+
+    if not retries_left:
+        logging.warn('giving up on %s: max retries exceed' % path)
+
+    return r
+
+
+def lookup_repo(db_session, repo_id):
+    return db_session.query(Repository) \
+                     .filter(Repository.id == repo_id) \
+                     .first()
+
+
+def last_repo_id(db_session):
+    t = db_session.query(func.max(Repository.id)) \
+                  .first()
+    if t is not None:
+        return t[0]
+    # else: return None
+
+
+INJECT_KEYS = ['id', 'name', 'full_name', 'html_url', 'description', 'fork']
+
+
+def inject_repo(db_session, repo):
+    logging.debug('injecting repo %d' % repo['id'])
+    if lookup_repo(db_session, repo['id']):
+        logging.info('not injecting already present repo %d' % repo['id'])
+        return
+    kwargs = {k: repo[k] for k in INJECT_KEYS if k in repo}
+    sql_repo = Repository(**kwargs)
+    db_session.add(sql_repo)
+
+
+class FetchError(RuntimeError):
+
+    def __init__(self, response):
+        self.response = response
+
+    def __str__(self):
+        return repr(self.response)
+
+
+def fetch(conf, mk_session, min_id=None, max_id=None):
+    if min_id is None:
+        min_id = 1
+    if max_id is None:
+        max_id = float('inf')
+    next_id = min_id
+
+    cred = {}
+    for key in ['username', 'password']:
+        if key in conf:
+            cred[key] = conf[key]
+
+    while min_id <= next_id <= max_id:
+        logging.info('listing repos starting at %d' % next_id)
+        since = next_id - 1  # github API ?since=... is '>' strict, not '>='
+        repos_res = gh_api_request('/repositories?since=%d' % since, **cred)
+
+        if 'cache_dir' in conf and conf['cache_json']:
+            save_http_response(repos_res, conf['cache_dir'])
+        if not repos_res.ok:
+            raise FetchError(repos_res)
+
+        repos = repos_res.json()
+        for repo in repos:
+            if repo['id'] > max_id:  # do not overstep max_id
+                break
+            with session_scope(mk_session) as db_session:
+                inject_repo(db_session, repo)
+
+        if 'next' in repos_res.links:
+            next_url = repos_res.links['next']['url']
+            m = REPO_API_URL_RE.match(next_url)  # parse next_id
+            next_id = int(m.group(1)) + 1
+        else:
+            logging.info('stopping after id %d, no next link found' % next_id)
+            break

swh/lister/github/models.py

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+# Copyright (C) 2015  Stefano Zacchiroli <zack@upsilon.cc>
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+from datetime import datetime
+
+from sqlalchemy import Column
+from sqlalchemy import Boolean, DateTime, Integer, String
+from sqlalchemy.ext.declarative import declarative_base
+
+
+SQLBase = declarative_base()
+
+
+class Repository(SQLBase):
+
+    """a GitHub repository"""
+
+    __tablename__ = 'repos'
+
+    id = Column(Integer, primary_key=True)
+
+    name = Column(String, index=True)
+    full_name = Column(String, index=True)
+    html_url = Column(String)
+    description = Column(String)
+    fork = Column(Boolean, index=True)
+
+    last_seen = Column(DateTime, nullable=False)
+
+    def __init__(self, id, name=None, full_name=None, html_url=None,
+                 description=None, fork=None):
+        self.id = id
+        self.last_seen = datetime.now()
+        if name is not None:
+            self.name = name
+        if full_name is not None:
+            self.full_name = full_name
+        if html_url is not None:
+            self.html_url = html_url
+        if description is not None:
+            self.description = description
+        if fork is not None:
+            self.fork = fork