RFE: Add ability to visualize the known topology

[Shachar Snapiri]

Add the ability to view the topology as known by DragonFlow in a graphical way.
This feature is needed to allow easier debugging of issues in flows and understanding the behaviour of DragonFlow.

Implementation stages:
1. Have a view of the topology of a specific network node
2. Have real-time updates of the information (items added/removed)
3. Allow aggregation of the information and have a global view of the topology
4. Allow filtering and dissecting of the information to show just specific parts
5. Allow simulation or tracing of packets in the system on the graphical interface.

All of these features are supported by skydive project, but for other collectors, we should implement our own collector (or a way to send the information to the analyser) in a way that will be out-of-band with the operation of the controller (or at least not block it for long periods) and allow an administrator (rather than developer) easy access and debugging of the system.

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/546106

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/546106
Committed: https://git.openstack.org/cgit/openstack/dragonflow/commit/?id=fc825d4586964d178f09802feb1c92fb09b4b586
Submitter: Zuul
Branch: master

commit fc825d4586964d178f09802feb1c92fb09b4b586
Author: Shachar Snapiri <email address hidden>
Date: Tue Feb 20 12:22:19 2018 +0200

    SPEC - Skydive integration

    Spec for the integration of the SkyDive project in Dragonflow.
    Still a few open issues (expect more to be there) - feedback is welcome

    Change-Id: I2045fe79423b43b98faef41dc35f28aa872a2b78
    Related-Bug: #1749429

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/554241

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/554489

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/554489
Committed: https://git.openstack.org/cgit/openstack/dragonflow/commit/?id=6605dd26bc22458924f9bf58bc5ebf475c99ca80
Submitter: Zuul
Branch: master

commit 6605dd26bc22458924f9bf58bc5ebf475c99ca80
Author: Shachar Snapiri <email address hidden>
Date: Tue Mar 20 11:55:17 2018 +0200

    Fix a typo in skydive spec

    Newlines were missing so the formatting was wrong

    Change-Id: I93b9043a794e124315f9f5795a72d27dee42fead
    Related-Bug: #1749429

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/518670
Committed: https://git.openstack.org/cgit/openstack/dragonflow/commit/?id=439e528addd2ee481e8039cec4ba5892725b7ff6
Submitter: Zuul
Branch: master

commit 439e528addd2ee481e8039cec4ba5892725b7ff6
Author: Dima Kuznetsov <email address hidden>
Date: Wed Nov 1 16:27:07 2017 +0200

    SkyDive agent app

    Initial sketch of app that reports DF objects to Skydive analyzer

    TODO:
    [X] Fix issues with Skydive - use 0.4.1
    [X] Investigate why main loop does not exit on stop
    [X] Add docstrings
    [X] Add links to the owner objects to get a more complete topology view
    [X] Add mechanism to remove deleted items

    The following will be in separate patches:
    [ ] Start as a separate daemon
    [ ] Handle DB disconnect/reconnect
    [ ] Get add/update/delete events from DF/DB

    Co-Authored-By: Omer Anson <email address hidden>
    Co-Authored-By: Shachar Snapiri <email address hidden>
    Related-Bug: #1749429
    Depends-On: I89f37e9590de86ca8d6f6a48cf1673ea214b6d29
    Change-Id: Ie715e340f9df1b1e250480d05ecd0341d28bda06

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/554241
Committed: https://git.openstack.org/cgit/openstack/dragonflow/commit/?id=7be2d258e2de97becccfc6804b323a28c274830f
Submitter: Zuul
Branch: master

commit 7be2d258e2de97becccfc6804b323a28c274830f
Author: Shachar Snapiri <email address hidden>
Date: Mon Mar 19 16:32:27 2018 +0200

    Add df_skydive_service to dragonflow

    To enable skydive, one should now enable the service in the local.conf
    file using the following line:
    enable_service df_skydive

    If you would like to install the SkyDive analyzer on the same node, the
    SkyDive install lines MUST be before the DragonFlow ones!
    Please see doc/source/single-node-conf/etcd_skydive_local_controller.conf
    file for usage example

    Change-Id: I66c3eaf18904ae1c109d0ca8007269c41261d791
    Depends-On: c5921051d7bc05d2c29494be842329e2ffcc008a
    Related-Bug: #1749429