CURRENT_USER, 'USER and SESSION_USER` system functions

CHANGES.txt

@@ -15,6 +15,12 @@ the appropriate section of the docs.
 Breaking Changes
 ================
 
+ - ``CURRENT_USER``, ``USER`` and ``SESSION_USER`` are now reserved words as we 
+   introduced them as system functions. These terms will not be available to 
+   be used as table, and column names and for already existing entities they 
+   will have to be quoted when referenced (otherwise the terms will be treated 
+   as function calls).
+
  - ``SELECT`` statements without any ``FROM`` items are no longer executed
    against the ``sys.cluster`` table, but against a virtual table with no
    columns. Queries including ``sys.cluster`` columns but no explicit ``FROM``

blackbox/docs/best_practice/data_import.txt

@@ -23,10 +23,10 @@ Defining the Data Structure
 Before starting the import you'll have to consider how your table structure
 will look. Decisions made at this point will influence the import process later.
 
-For this example we have a simple single ``user`` table with 6 columns of
+For this example we have a simple single ``users`` table with 6 columns of
 various types::
 
-  cr> CREATE TABLE user (
+  cr> CREATE TABLE users (
   ...   id INT primary key,
   ...   name STRING,
   ...   day_joined TIMESTAMP,
@@ -40,7 +40,7 @@ various types::
 
 .. hide:
 
-  cr> DROP TABLE user;
+  cr> DROP TABLE users;
   DROP OK, 1 row affected (... sec)
 
 There's nothing wrong with this method and it does the job, but it's not very
@@ -80,7 +80,7 @@ according to your availability requirements.
 
 The ``CREATE TABLE`` statement now looks like::
 
-  cr> CREATE TABLE user (
+  cr> CREATE TABLE users(
   ...   id INT primary key,
   ...   name STRING,
   ...   day_joined TIMESTAMP,
@@ -107,17 +107,17 @@ therefore also minimise the overhead during import.
 
 ::
 
-  cr> ALTER TABLE user SET (refresh_interval = 0);
+  cr> ALTER TABLE users SET (refresh_interval = 0);
   ALTER OK, -1 rows affected (... sec)
 
 .. hide:
 
-  cr> DROP TABLE user;
+  cr> DROP TABLE users;
   DROP OK, 1 row affected (... sec)
 
 It's possible to set the refresh interval in the ``CREATE TABLE`` statement::
 
-  cr> CREATE TABLE user (
+  cr> CREATE TABLE users (
   ...   id INT primary key,
   ...   name STRING,
   ...   day_joined TIMESTAMP,
@@ -136,7 +136,7 @@ It's possible to set the refresh interval in the ``CREATE TABLE`` statement::
 Once the import is finished you can set the refresh interval to a reasonable
 value (time in ms)::
 
-  cr> ALTER TABLE user SET (refresh_interval = 1000);
+  cr> ALTER TABLE users SET (refresh_interval = 1000);
   ALTER OK, -1 rows affected (... sec)
 
 .. seealso::
@@ -212,18 +212,18 @@ will return successfully, reporting ``COPY OK, 0 rows affected (... sec)``.
 
 ::
 
-  cr> COPY user FROM '/tmp/best_practice_data/users.json';
+  cr> COPY users FROM '/tmp/best_practice_data/users.json';
   COPY OK, 150 rows affected (... sec)
 
 .. hide:
 
-  cr> REFRESH TABLE user;
+  cr> REFRESH TABLE users;
   REFRESH OK, 1 row affected (... sec)
 
-  cr> delete from user;
+  cr> delete from users;
   DELETE OK, 150 rows affected (... sec)
 
-  cr> REFRESH TABLE user;
+  cr> REFRESH TABLE users;
   REFRESH OK, 1 row affected (... sec)
 
 .. note::
@@ -242,19 +242,19 @@ defaults to 10 000 if not specified.
 
 For example::
 
-  cr> COPY user FROM '/tmp/best_practice_data/users.json'
+  cr> COPY users FROM '/tmp/best_practice_data/users.json'
   ... WITH (bulk_size = 2000);
   COPY OK, 150 rows affected (... sec)
 
 .. hide:
 
-  cr> REFRESH TABLE user;
+  cr> REFRESH TABLE users;
   REFRESH OK, 1 row affected (... sec)
 
-  cr> delete from user;
+  cr> delete from users;
   DELETE OK, 150 rows affected (... sec)
 
-  cr> REFRESH TABLE user;
+  cr> REFRESH TABLE users;
   REFRESH OK, 1 row affected (... sec)
 
 In our example it will not make a difference, but if you have a more complex
@@ -274,13 +274,13 @@ CrateDB does not automatically detect compression, so you'll need to specify
 
 For example::
 
-  cr> COPY user FROM '/tmp/best_practice_data/users.json.gz'
+  cr> COPY users FROM '/tmp/best_practice_data/users.json.gz'
   ... WITH (compression = 'gzip');
   COPY OK, 150 rows affected (... sec)
 
 .. hide:
 
-  cr> REFRESH TABLE user;
+  cr> REFRESH TABLE users;
   REFRESH OK, 1 row affected (... sec)
 
 Partitioned Tables
@@ -300,12 +300,12 @@ partition column.
 
 .. hide:
 
-  cr> DROP TABLE user;
+  cr> DROP TABLE users;
   DROP OK, 1 row affected (... sec)
 
 ::
 
-  cr> CREATE TABLE user (
+  cr> CREATE TABLE users (
   ...   id INT primary key,
   ...   name STRING,
   ...   day_joined TIMESTAMP primary key,
@@ -333,7 +333,7 @@ For example: ``users_1408312800.json``
 The value of the partition column must be defined in the ``COPY FROM``
 statement using the ``PARTITION`` clause::
 
-  cr> COPY user PARTITION (day_joined=1408312800)
+  cr> COPY users PARTITION (day_joined=1408312800)
   ... FROM '/tmp/best_practice_data/users_1408312800.json';
   COPY OK, 23 rows affected (... sec)
 

blackbox/docs/enterprise/index.txt

@@ -15,6 +15,10 @@ Current features:
   more
 - :ref:`Support for JavaScript in UDF <udf_lang_js>`: write user-defined
   functions in JavaScript
+- System Information Functions: 
+    - :ref:`Current user function <current_user>`
+    - :ref:`User function <user>`
+    - :ref:`Session user function <session_user>`
 
 .. _`enterprise edition`: https://crate.io/enterprise-edition/
 .. _`enterprise license`: https://crate.io/enterprise-edition/

blackbox/docs/sql/administration/user_management.txt

@@ -102,6 +102,12 @@ To list all existing users query that table::
 The column ``name`` shows the unique name of the user, the column ``superuser``
 shows whether the user has superuser privileges or not.
 
+.. note::
+
+    CrateDB also supports retrieving the current connected user using the 
+    system information functions: :ref:`CURRENT_USER <current_user>`, 
+    :ref:`USER <user>` and :ref:`SESSION_USER <session_user>`.
+
 .. warning::
 
    When the :ref:`es_api_setting` is enabled, it is possible to read the users

blackbox/docs/sql/scalar.txt

@@ -1621,9 +1621,11 @@ The default schema can be set when using the `JDBC
 <https://crate.io/docs/reference/protocols/http.html#default-schema>`_ such as
 `CrateDB PDO`_.
 
-The ``CURRENT_SCHEMA`` function has a special SQL syntax, meaning that it must
-be called without trailing parenthesis (``()``). However, CrateDB also supports
-the optional parenthesis.
+.. note::
+
+    The ``CURRENT_SCHEMA`` function has a special SQL syntax, meaning that it 
+    must be called without trailing parenthesis (``()``). However, CrateDB also 
+    supports the optional parenthesis.
 
 Synopsis::
 
@@ -1639,6 +1641,101 @@ Example::
     +----------------+
     SELECT 1 row in set (... sec)
 
+.. _current_user:
+
+``CURRENT_USER``
+----------------
+
+.. NOTE::
+
+   ``CURRENT_USER`` is an Enterprise Edition feature.
+
+The ``CURRENT_USER`` system information function returns the name of the 
+current connected user or NULL if the user management module is disabled.
+
+Returns: ``string``
+
+Synopsis::
+
+    CURRENT_USER 
+
+Example::
+
+    cr> select current_user;
+    +--------------+
+    | current_user |
+    +--------------+
+    | crate        |
+    +--------------+
+    SELECT 1 row in set (... sec)
+
+.. _user:
+
+``USER``
+--------
+
+.. NOTE::
+
+   ``USER`` is an Enterprise Edition feature.
+
+Equivalent to `CURRENT_USER`_.
+
+Returns: ``string``
+
+Synopsis::
+
+    USER 
+
+Example::
+
+    cr> select user;
+    +--------------+
+    | current_user |
+    +--------------+
+    | crate        |
+    +--------------+
+    SELECT 1 row in set (... sec)
+
+.. _session_user:
+
+``SESSION_USER``
+----------------
+
+.. NOTE::
+
+   ``SESSION_USER`` is an Enterprise Edition feature.
+
+The ``SESSION_USER`` system information function returns the name of the
+current connected user or NULL if the user management module is disabled.
+
+Returns: ``string``
+
+Synopsis::
+
+    SESSION_USER
+
+Example::
+
+    cr> select session_user;
+    +--------------+
+    | session_user |
+    +--------------+
+    | crate        |
+    +--------------+
+    SELECT 1 row in set (... sec)
+
+.. note::
+
+    CrateDB doesn't currently support the switching of execution context. This
+    makes `SESSION_USER`_ functionally equivalent to `CURRENT_USER`_. We
+    provide it as it's part of the SQL standard.
+
+.. note::
+
+    The `CURRENT_USER`_, `SESSION_USER`_ and `USER`_ functions have a  
+    a special SQL syntax, meaning that they must be called without trailing 
+    parenthesis (``()``).
+
 .. rubric:: Footnotes
 
 .. [#MySQL-Docs] http://dev.mysql.com/doc/refman/5.6/en/date-and-time-functions.html#function_date-format

enterprise/users/src/main/java/io/crate/plugin/UsersPlugin.java

@@ -1,42 +1,47 @@
 /*
- * Licensed to Crate under one or more contributor license agreements.
- * See the NOTICE file distributed with this work for additional
- * information regarding copyright ownership.  Crate licenses this file
- * to you under the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.  You may
- * obtain a copy of the License at
+ * This file is part of a module with proprietary Enterprise Features.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ * Licensed to Crate.io Inc. ("Crate.io") under one or more contributor
+ * license agreements.  See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
- * implied.  See the License for the specific language governing
- * permissions and limitations under the License.
+ * Unauthorized copying of this file, via any medium is strictly prohibited.
  *
- * However, if you have executed another commercial license agreement
- * with Crate these terms will supersede the license and you may use the
- * software solely pursuant to the terms of the relevant commercial
- * agreement.
+ * To use this file, Crate.io must have given you permission to enable and
+ * use such Enterprise Features and you must have a valid Enterprise or
+ * Subscription Agreement with Crate.io.  If you enable or use the Enterprise
+ * Features, you represent and warrant that you have a valid Enterprise or
+ * Subscription Agreement with Crate.io.  Your use of the Enterprise Features
+ * if governed by the terms and conditions of your Enterprise or Subscription
+ * Agreement with Crate.io.
  */
 
 package io.crate.plugin;
 
 import io.crate.metadata.UsersMetaData;
 import io.crate.metadata.UsersPrivilegesMetaData;
+import io.crate.scalar.UsersScalarFunctionModule;
+import io.crate.settings.SharedSettings;
 import org.elasticsearch.cluster.NamedDiff;
 import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.inject.Module;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
+import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.plugins.Plugin;
 
 import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.List;
 
 public class UsersPlugin extends Plugin {
 
-    public UsersPlugin() {
+    private final Settings settings;
+
+    public UsersPlugin(Settings settings) {
+        this.settings = settings;
     }
 
     @Override
@@ -81,4 +86,13 @@ public List<NamedXContentRegistry.Entry> getNamedXContent() {
         ));
         return entries;
     }
+
+    @Override
+    public Collection<Module> createGuiceModules() {
+        if (SharedSettings.ENTERPRISE_LICENSE_SETTING.setting().get(settings)) {
+            return Collections.singletonList(new UsersScalarFunctionModule());
+        } else {
+            return Collections.emptyList();
+        }
+    }
 }