Adding Apex docs for Plugins module

Change-Id: Icf68473b472a5896972de5b07b275682a77a1c9f
Signed-off-by: Dinh Danh Le <dinh.danh.le@ericsson.com>
Issue-ID: POLICY-867

5 files changed, 174 insertions, 0 deletions

diff --git a/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/ct-websocket-io.adoc b/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/ct-websocket-io.adoc
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--- /dev/null
+++ b/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/ct-websocket-io.adoc
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+//
+// ============LICENSE_START=======================================================
+//  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+// ================================================================================
+// This file is licensed under the CREATIVE COMMONS ATTRIBUTION 4.0 INTERNATIONAL LICENSE
+// Full license text at https://creativecommons.org/licenses/by/4.0/legalcode
+// 
+// SPDX-License-Identifier: CC-BY-4.0
+// ============LICENSE_END=========================================================
+//
+// @author Sven van der Meer (sven.van.der.meer@ericsson.com)
+//
+
+== Websocket (WS) IO
+
+APEX supports the Websockets as input as well as output.
+WS IO is supported by the APEX Websocket plugin.
+This carrier technology does only support uni-directional communication.
+APEX will not send events to a Websocket input and any event sent to a Websocket output will result in an error log.
+
+The input can be configured as client (APEX connects to an existing Websocket server) or server (APEX starts a Websocket server).
+The same applies to the output.
+Input and output can both use a client or a server configuration, or separate configurations (input as client and output as server, input as server and output as client).
+Each configuration should use its own dedicated port to avoid any communication loops.
+The configuration of a Websocket client is the same for input and output.
+The configuration of a Websocket server is the same for input and output.
+
+
+=== Websocket Client
+
+APEX will connect to a given Websocket server.
+As input, it will receive events from the server but not send any events.
+As output, it will send events to the server and any event received from the server will result in an error log.
+
+[source%nowrap,json]
+----
+"carrierTechnologyParameters" : {
+  "carrierTechnology" : "WEBSOCKET", <1>
+  "parameterClassName" :
+  "org.onap.policy.apex.plugins.event.carrier.websocket.WEBSOCKETCarrierTechnologyParameters",
+  "parameters" : {
+    "host" : "localhost", <2>
+    "port" : 42451 <3>
+  }
+}
+----
+
+<1> set Websocket as carrier technology
+<2> the host name on which a Websocket server is running
+<3> the port of that Websocket server
+
+
+
+=== Websocket Server
+
+APEX will start a Websocket server, which will accept any Websocket clients to connect.
+As input, it will receive events from the server but not send any events.
+As output, it will send events to the server and any event received from the server will result in an error log.
+
+[source%nowrap,json]
+----
+"carrierTechnologyParameters" : {
+  "carrierTechnology" : "WEBSOCKET", <1>
+  "parameterClassName" :
+  "org.onap.policy.apex.plugins.event.carrier.websocket.WEBSOCKETCarrierTechnologyParameters",
+  "parameters" : {
+    "wsClient" : false, <2>
+    "port"     : 42450 <3>
+  }
+}
+----
+
+<1> set Websocket as carrier technology
+<2> disable client, so that APEX will start a Websocket server
+<3> the port for the Websocket server APEX will start
diff --git a/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/engine-config-bcp.adoc b/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/engine-config-bcp.adoc
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+++ b/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/engine-config-bcp.adoc
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+//
+// ============LICENSE_START=======================================================
+//  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+// ================================================================================
+// This file is licensed under the CREATIVE COMMONS ATTRIBUTION 4.0 INTERNATIONAL LICENSE
+// Full license text at https://creativecommons.org/licenses/by/4.0/legalcode
+// 
+// SPDX-License-Identifier: CC-BY-4.0
+// ============LICENSE_END=========================================================
+//
+// @author Sven van der Meer (sven.van.der.meer@ericsson.com)
+//
+
+== BCP: Websocket Configuration
+
+The probably best is to configure APEX for Websocket servers for input (ingress, consume) and output (egress, produce) interfaces.
+This means that APEX will start Websocket servers on named ports and wait for clients to connect.
+Advantage: once APEX is running all connectivity infrastructure is running as well.
+Consequence: if APEX is not running, everyone else is in the dark, too.
+
+The best protocol to be used is JSON string.
+Each event on any interface is then a string with a JSON encoding.
+JSON string is a little bit slower than byte code, but we doubt that this will be noticeable.
+A further advantage of JSON strings over Websockets with APEX starting the servers: it is very easy to connect web browsers to such a system.
+Simple connect the web browser to the APEX sockets and send/read JSON strings.
+
+Once APEX is started you simply connect Websocket clients to it, and send/receive event.
+When APEX is terminated, the Websocket servers go down, and the clients will be disconnected.
+APEX does not (yet) support auto-client reconnect nor WAMP, so clients might need to be restarted or reconnected manually after an APEX boot.
diff --git a/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/ws-foss.adoc b/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/ws-foss.adoc
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+++ b/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/ws-foss.adoc
@@ -0,0 +1,27 @@
+//
+// ============LICENSE_START=======================================================
+//  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+// ================================================================================
+// This file is licensed under the CREATIVE COMMONS ATTRIBUTION 4.0 INTERNATIONAL LICENSE
+// Full license text at https://creativecommons.org/licenses/by/4.0/legalcode
+// 
+// SPDX-License-Identifier: CC-BY-4.0
+// ============LICENSE_END=========================================================
+//
+// @author Sven van der Meer (sven.van.der.meer@ericsson.com)
+//
+
+== Websocket Example Code for Websocket clients (FOSS)
+
+There are a lot of implementations and examples available on Github for Websocket clients.
+If one is using Java EE 7, then one can also use the native Websocket implementation.
+Good examples for clients using simply Java SE are here:
+
+- link:https://github.com/TooTallNate/Java-WebSocket[Websocket implementation]
+- link:https://github.com/TooTallNate/Java-WebSocket/blob/master/src/main/example/ChatClient.java[Websocket sending client example, using AWT]
+- link:https://github.com/TooTallNate/Java-WebSocket/blob/master/src/main/example/ExampleClient.java[Websocket receiving client example (simple echo client)]
+
+For Java EE, the native Websocket API is explained here:
+
+- link:http://www.oracle.com/technetwork/articles/java/jsr356-1937161.html[Oracle docs]
+- link: http://www.programmingforliving.com/2013/08/jsr-356-java-api-for-websocket-client-api.html[An example]
diff --git a/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/ws-intro.adoc b/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/ws-intro.adoc
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+++ b/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/ws-intro.adoc
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+//
+// ============LICENSE_START=======================================================
+//  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+// ================================================================================
+// This file is licensed under the CREATIVE COMMONS ATTRIBUTION 4.0 INTERNATIONAL LICENSE
+// Full license text at https://creativecommons.org/licenses/by/4.0/legalcode
+// 
+// SPDX-License-Identifier: CC-BY-4.0
+// ============LICENSE_END=========================================================
+//
+// @author Sven van der Meer (sven.van.der.meer@ericsson.com)
+//
+
+== Websockets
+
+Websocket is a protocol to run sockets of HTTP.
+Since it in essence a socket, the connection is realized between a server (waiting for connections) and a client (connecting to a server).
+Server/client separation is only important for connection establishment, once connected, everyone can send/receive on the same socket (as any standard socket would allow). 
+
+Standard Websocket implementations are simple, no publish/subscribe and no special event handling.
+Most servers simply send all incoming messages to all connections.
+There is a PubSub definition on top of Websocket called link:http://wamp-proto.org/[WAMP].
+APEX does not support WAMP at the moment.
diff --git a/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/ws-java.adoc b/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/ws-java.adoc
new file mode 100644
index 000000000..e6c2c0163
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+++ b/plugins/plugins-event/plugins-event-carrier/plugins-event-carrier-websocket/src/site-docs/adoc/fragments/ws-java.adoc
@@ -0,0 +1,20 @@
+//
+// ============LICENSE_START=======================================================
+//  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+// ================================================================================
+// This file is licensed under the CREATIVE COMMONS ATTRIBUTION 4.0 INTERNATIONAL LICENSE
+// Full license text at https://creativecommons.org/licenses/by/4.0/legalcode
+// 
+// SPDX-License-Identifier: CC-BY-4.0
+// ============LICENSE_END=========================================================
+//
+// @author Sven van der Meer (sven.van.der.meer@ericsson.com)
+//
+
+== Websocket in Java
+
+In Java, link:http://www.oracle.com/technetwork/articles/java/jsr356-1937161.html[JSR 356] defines the standard Websocket API.
+This JSR is part of Jave EE 7 standard.
+For Java SE, several implementations exist in open source.
+Since Websockets are a stable standard and simple, most implementations are stable and ready to use.
+A lot of products support Websockets, like Spring, JBoss, Netty, … there are also Kafka extensions for Websockets.