[server] Add a liveness and readiness urls

Add 2 new url endpoints:
 - `localhost:8001/live`: simply say that the server is running. In case of succes it will response with 200 status code and a `CODECHECKER_SERVER_IS_LIVE` message.
 - `localhost:8001/ready`: it will run a simple query on the database. In case of success it will response with 200 status code and a `CODECHECKER_SERVER_IS_READY` message. In case of error it will response with 500 error code and a `CODECHECKER_SERVER_IS_NOT_READY` error message.

docs/web/docker.md

@@ -7,6 +7,19 @@ packaged with all its dependencies and libraries.
 To see how you can run a CodeChecker server in Docker read the following
 sections.
 
+## Table of Contents
+* [Build Docker image](#build-docker-image)
+* [Pre-built CodeChecker Docker images](#pre-built-codechecker-docker-images)
+* [Usage](#usage)
+* [Docker compose](#docker-compose)
+  * [docker-compose.yml](#docker-composeyml)
+    * [Sqlite setup](#sqlite-setup)
+    * [PostgreSQL setup](#postgresql-setup)
+      * [PostgreSQL (no authentication)](#postgresql-no-authentication)
+      * [PostgreSQL (authentication)](#postgresql-authentication)
+    * [Running your app](#running-your-app)
+* [Kubernetes](#kubernetes)
+
 ## Build Docker image
 You can create a Docker image by running the following command in the root
 directory of this repository:
@@ -110,3 +123,20 @@ previously created password files for secrets.
 ### Running your app
 Run `docker-compose -f web/docker/services/<service-yml-file> up -d` and
 Compose starts and runs your entire app.
+
+## Kubernetes
+[![Kubernetes](../images/kubernetes.png)](https://kubernetes.io/)
+
+CodeChecker supports to configure liveness, readiness and startup probes for
+containers when using
+[Kubernetes]( https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/).
+
+If your server is running on `my.company.org` at `8080` port then two URL
+endpoints will be available for you:
+* `my.company.org:8080/live`: simply say that the server is running. In case of
+succes it will response with `200` status code and a
+`CODECHECKER_SERVER_IS_LIVE` message.
+* `my.company.org:8080/ready`: it will run a simple query on the database. In
+case of success it will response with `200` status code and a
+`CODECHECKER_SERVER_IS_READY` message. In case of error it will response with
+`500` error code and a `CODECHECKER_SERVER_IS_NOT_READY` error message.

web/server/codechecker_server/routing.py

@@ -28,7 +28,9 @@
                          'scripts',
                          'style',
                          'userguide',
-                         'docs']
+                         'docs',
+                         'live',
+                         'ready']
 
 # A list of top-level path elements in requests (such as Thrift endpoints)
 # which should not be considered as a product route.

web/server/codechecker_server/server.py

@@ -63,7 +63,8 @@
 from .api.report_server import ThriftRequestHandler as ReportHandler_v6
 from .database import database
 from .database import db_cleanup
-from .database.config_db_model import Product as ORMProduct
+from .database.config_db_model import Product as ORMProduct, \
+    Configuration as ORMConfiguration
 from .database.run_db_model import IDENTIFIER as RUN_META, Run, RunLock
 
 LOG = get_logger('server')
@@ -154,6 +155,30 @@ def __has_access_permission(self, product):
                 perm_args,
                 self.auth_session)
 
+    def __handle_readiness(self):
+        """ Handle readiness probe. """
+        try:
+            cfg_sess = self.server.config_session()
+            cfg_sess.query(ORMConfiguration).count()
+
+            self.send_response(200)
+            self.end_headers()
+            self.wfile.write('CODECHECKER_SERVER_IS_READY')
+        except Exception:
+            self.send_response(500)
+            self.end_headers()
+            self.wfile.write('CODECHECKER_SERVER_IS_NOT_READY')
+        finally:
+            if cfg_sess:
+                cfg_sess.close()
+                cfg_sess.commit()
+
+    def __handle_liveness(self):
+        """ Handle liveness probe. """
+        self.send_response(200)
+        self.end_headers()
+        self.wfile.write('CODECHECKER_SERVER_IS_LIVE')
+
     def end_headers(self):
         # Sending the authentication cookie
         # in every response if any.
@@ -189,6 +214,14 @@ def do_GET(self):
 
         product_endpoint, path = routing.split_client_GET_request(self.path)
 
+        if self.path == '/live':
+            self.__handle_liveness()
+            return
+
+        if self.path == '/ready':
+            self.__handle_readiness()
+            return
+
         if self.server.manager.is_enabled and not self.auth_session \
                 and routing.is_protected_GET_entrypoint(path):
             # If necessary, prompt the user for authentication.