adding an entrypoint script

Author: ricardogsilva

.dockerignore

@@ -16,5 +16,8 @@ tests/results
 # test configurations
 /default.cfg
 
+# git stuff
+.git
+
 # pycharm ide
 .idea

Dockerfile

@@ -32,6 +32,7 @@ RUN echo 'http://dl-cdn.alpinelinux.org/alpine/v3.1/main' >> /etc/apk/repositori
     libxslt-dev \
     'libxml2<2.9.4' \
     'libxml2-dev<2.9.4' \
+    netcat-openbsd \
     wget \
   && apk add --no-cache \
     --repository http://dl-3.alpinelinux.org/alpine/edge/testing/ \
@@ -54,10 +55,7 @@ USER pycsw
 
 EXPOSE 8000
 
-ENTRYPOINT [ \
-  "gunicorn", \
-  "--workers=2", \
-  "--bind=0.0.0.0:8000", \
-  "--access-logfile=-", \
-  "pycsw.wsgi" \
+ENTRYPOINT [\
+  "python3", \
+  "/home/pycsw/bin/entrypoint.py" \
 ]

bin/entrypoint.py

@@ -0,0 +1,116 @@
+"""Entrypoint script for docker containers.
+
+This module serves as the entrypoint for docker containers. Its main
+purpose is to set up the pycsw database so that newly generated
+containers may be useful soon after being launched, without requiring
+additional input.
+
+"""
+
+
+import argparse
+from collections import namedtuple
+import logging
+import os
+from six.moves.configparser import SafeConfigParser
+from subprocess import call
+from subprocess import PIPE
+from time import sleep
+
+from pycsw.core import admin
+
+logger = logging.getLogger(__name__)
+
+DatabaseParameters = namedtuple("DatabaseParameters", [
+    "host",
+    "port",
+    "user",
+    "password",
+    "path"
+])
+
+
+def launch_pycsw(gunicorn_workers=2):
+    logger.debug("Reading pycsw config...")
+    config = SafeConfigParser()
+    config.read("/etc/pycsw/pycsw.cfg")
+    db_url = config.get("repository", "database")
+    db = db_url.partition(":")[0].partition("+")[0]
+    db_handler = {
+        "sqlite": handle_sqlite_db,
+        "postgres": handle_postgresql_db,
+    }.get(db)
+    logger.debug("Setting up pycsw's data repository...")
+    logger.debug("Repository URL: {}".format(db_url))
+    db_handler(db_url, config.get("repository", "table"))
+    logger.debug("Launching pycsw...")
+    pycsw_server_command = [
+        "gunicorn",
+        "--bind=0.0.0.0:8000",
+        "--access-logfile=-",
+        "--error-logfile=-",
+        "--workers={}".format(gunicorn_workers)
+    ]
+    pycsw_server_command.append("--workers={}".format(gunicorn_workers))
+    pycsw_server_command.append("pycsw.wsgi")
+    call(pycsw_server_command)
+
+
+def handle_sqlite_db(database_url, table_name):
+    db_path = database_url.rpartition(":///")[-1]
+    if not os.path.isfile(db_path):
+        _create_pycsw_schema(database_url, table_name)
+
+
+def handle_postgresql_db(database_url, table_name):
+    db_params = _extract_postgres_url_params(database_url)
+    _wait_for_network_service(db_params.host, db_params.port)
+    # - set up the db with pycsw-admin if needed
+    _create_pycsw_schema(database_url, table_name)
+    raise NotImplementedError
+
+
+def _extract_postgres_url_params(database_url):
+    db_params = database_url.partition("://")[-1]
+    rest, db_name = db_params.rpartition("/")[::2]
+    user_params, host_params = rest.partition("@")[::2]
+    user, password = user_params.partition(":")[::2]
+    host, port = host_params.partition(":")[::2]
+    port = port if port != "" else "5432"
+    return DatabaseParameters(host, port, user, password, db_name)
+
+
+def _create_pycsw_schema(database_url, table):
+    admin.setup_db(database=database_url, table=table, home="/home/pycsw")
+
+
+def _wait_for_network_service(host, port, max_tries=10, wait_seconds=3):
+    logger.debug("Waiting for {!r}:{!r}...".format(host, port))
+    current_try = 0
+    while current_try < max_tries:
+        return_code = call(
+            ["nc", "-z", str(host), str(port)], stdout=PIPE, stderr=PIPE)
+        if int(return_code) == 0:
+            logger.debug("{!r}:{!r} is already up!".format(host, port))
+            break
+        else:
+            current_try += 1
+            sleep(wait_seconds)
+    else:
+        raise RuntimeError("Could not find {}:{} after {} tries. "
+                           "Giving up".format(host, port, max_tries))
+
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--verbose", action="store_true")
+    parser.add_argument(
+        "--workers",
+        default=2,
+        help="Number of workers to use by the gunicorn server. Defaults to 2."
+    )
+    args, remaining_args = parser.parse_known_args()
+    logging.basicConfig(
+        level=logging.DEBUG if args.verbose else logging.WARNING)
+    launch_pycsw(gunicorn_workers=args.workers)