Make collector configurable in DevStack plugin

In DevStack OSProfiler is by default configured to use messaging
driver with Ceilometer backend. User can change the driver, but
still needs to install collector/storage manually. This patch
introduces configuration option `OSPROFILER_COLLECTOR` which is
used to specify which collector/storage to install into DevStack.

Currently 2 values are supported:
 * `redis` to install Redis server and use Redis driver
 * <empty> to keep the default behavior and use messaging driver

To test the patch on DevStack, the following lines are needed in local.conf:
  enable_plugin osprofiler https://git.openstack.org/openstack/osprofiler refs/changes/06/527406/5
  OSPROFILER_BRANCH=refs/changes/06/527406/5
  OSPROFILER_COLLECTOR=redis

Change-Id: Ia9763605db95b3f35c8b0e51211f96ee0dd3a82d

1 files changed, 49 insertions, 14 deletions

diff --git a/devstack/README.rst b/devstack/README.rst
index 9e5b752..2cf7d20 100644
--- a/devstack/README.rst
+++ b/devstack/README.rst
@@ -5,29 +5,58 @@ Enabling OSProfiler using DevStack
 This directory contains the files necessary to run OpenStack with enabled
 OSProfiler in DevStack.
 
-OSProfiler has different drivers for trace processing. The default driver uses
-Ceilometer to process and store trace events. Other drivers may connect
-to databases directly and do not require Ceilometer.
+OSProfiler can send trace data into different collectors. There are 2 parameters
+that control this:
+
+* ``OSPROFILER_COLLECTOR`` specifies which collector to install in DevStack.
+  By default OSProfiler plugin does not install anything, thus default
+  messaging driver with Ceilometer storage will be used.
+
+  Possible values:
+
+  * ``<empty>`` - default messaging driver with Ceilometer is used
+  * ``redis`` - Redis is installed
+
+  The default value of ``OSPROFILER_CONNECTION_STRING`` is set automatically
+  depending on ``OSPROFILER_COLLECTOR`` value.
+
+* ``OSPROFILER_CONNECTION_STRING`` specifies which driver is used by OSProfiler.
+
+  Possible values:
+
+  * ``messaging://`` - use messaging as trace collector (with the transport configured by oslo.messaging)
+  * ``redis://host:port`` - use Redis as trace storage
+  * ``elasticsearch://host:port`` - use Elasticsearch as trace storage
+  * ``mongodb://host:port`` - use MongoDB as trace storage
+  * ``loginsight://username:password@host`` - use LogInsight as trace collector/storage
+
 
 To configure DevStack and enable OSProfiler edit ``${DEVSTACK_DIR}/local.conf``
 file and add the following to ``[[local|localrc]]`` section:
 
-  * to use specified driver::
+* to use Redis collector::
+
+      enable_plugin osprofiler https://git.openstack.org/openstack/osprofiler master
+      OSPROFILER_COLLECTOR=redis
 
-    enable_plugin osprofiler https://git.openstack.org/openstack/osprofiler master
-    OSPROFILER_CONNECTION_STRING=<connection string value>
+  OSProfiler plugin will install Redis and configure OSProfiler to use Redis driver
 
-    the driver is chosen depending on the value of
-    ``OSPROFILER_CONNECTION_STRING`` variable (refer to the next section for
-    details)
+* to use specified driver::
 
-  * to use default Ceilometer driver::
+      enable_plugin osprofiler https://git.openstack.org/openstack/osprofiler master
+      OSPROFILER_CONNECTION_STRING=<connection string value>
 
-    enable_plugin panko https://git.openstack.org/openstack/panko master
-    enable_plugin ceilometer https://git.openstack.org/openstack/ceilometer master
-    enable_plugin osprofiler https://git.openstack.org/openstack/osprofiler master
+  the driver is chosen depending on the value of
+  ``OSPROFILER_CONNECTION_STRING`` variable (refer to the next section for
+  details)
 
-  .. note:: The order of enabling plugins matters.
+* to use default Ceilometer driver::
+
+      enable_plugin panko https://git.openstack.org/openstack/panko master
+      enable_plugin ceilometer https://git.openstack.org/openstack/ceilometer master
+      enable_plugin osprofiler https://git.openstack.org/openstack/osprofiler master
+
+  Note: the order of enabling plugins matters.
 
 Run DevStack as normal::
 
@@ -52,3 +81,9 @@ Example: enable ElasticSearch driver with the server running on localhost::
 
     OSPROFILER_CONNECTION_STRING=elasticsearch://127.0.0.1:9200
 
+**OSPROFILER_COLLECTOR** - controls which collector to install into DevStack.
+The driver is then chosen automatically based on the collector. Empty value assumes
+that the default messaging driver with Ceilometer is used.
+Example: enable Redis collector::
+
+    OSPROFILER_COLLECTOR=redis