docs overview page, reworked intro page

docs/src/main/docs/about/01_overview.adoc

@@ -0,0 +1,102 @@
+///////////////////////////////////////////////////////////////////////////////
+
+    Copyright (c) 2019 Oracle and/or its affiliates. All rights reserved.
+
+    Licensed 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
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    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.
+
+///////////////////////////////////////////////////////////////////////////////
+
+= Overview
+:description: Helidon documentation
+:keywords: helidon, java, microservices, microprofile, documentation
+
+== Get going
+
+[PILLARS]
+====
+[CARD]
+.Getting Started
+[icon=assistant,link=getting-started/02_base-example.adoc]
+--
+Quickly create your first application, in under 2 minutes.
+--
+
+[CARD]
+.Guides
+[icon=explore,link=guides/01_overview.adoc]
+--
+Follow step-by-step guides to build your applications.
+--
+====
+
+== Components
+
+[PILLARS]
+====
+[CARD]
+.WebServer
+[icon=settings_ethernet,link=webserver/01_introduction.adoc]
+--
+A programmatic HTTP API with reactive features, powered by Netty.
+--
+
+[CARD]
+.Config
+[icon=settings,link=config/01_introduction.adoc]
+--
+A flexible configuration framework with support for multiple sources and
+ formats.
+--
+
+[CARD]
+.Security
+[icon=security,link=security/01_introduction.adoc]
+--
+A tool-chain to handle authentication, authorization and context propagation.
+--
+
+[CARD]
+.MicroProfile
+[icon=widgets,link=microprofile/01_introduction.adoc]
+--
+A platform definition that is familiar to enterprise Java developers.
+--
+
+[CARD]
+.Extensions
+[icon=extension,link=extensions/01_overview.adoc]
+--
+A set of add-ons for your Helidon-based applications.
+--
+
+[CARD]
+.Metrics
+[icon=av_timer,link=metrics/01_metrics.adoc]
+--
+Instrumentation to expose metrics of your applications.
+--
+
+[CARD]
+.Tracing
+[icon=timeline,link=tracing/01_tracing.adoc]
+--
+Profile and monitor your applications across multiple services.
+--
+
+[CARD]
+.Health Checks
+[icon=favorite_outline,link=health/01_health.adoc]
+--
+Expose health statuses of your applications.
+--
+====

docs/src/main/docs/about/02_introduction.adoc

@@ -0,0 +1,62 @@
+///////////////////////////////////////////////////////////////////////////////
+
+    Copyright (c) 2018, 2019 Oracle and/or its affiliates. All rights reserved.
+
+    Licensed 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
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    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.
+
+///////////////////////////////////////////////////////////////////////////////
+
+= Introduction
+:description: about Helidon
+:keywords: helidon, java, microservices, microprofile
+
+== A collection of Java libraries
+
+Helidon is a collection of Java libraries for writing microservices.
+
+There's no need for any specific tooling or deployment model. Simply use your
+ favorite tools !
+
+NOTE: Your microservice is a plain Java application. You do not need an
+ application server.
+
+== Cloud-native Java
+
+Helidon libraries interoperate with popular tools from the cloud-native space:
+
+* https://www.docker.com/[Docker]
+* https://kubernetes.io/[Kubernetes]
+* https://prometheus.io/[Prometheus]
+* https://opentracing.io/[OpenTracing]
+* https://coreos.com/etcd/[Etcd]
+
+TIP: The <<getting-started/02_base-example.adoc,Helidon Quickstart Examples>>
+ contain support for Docker and Kubernetes.
+
+== Helidon SE
+
+Helidon SE is the functional programming style provided by all Helidon
+ libraries.
+
+NOTE: Helidon SE gives you full transparency and puts you in control. There is
+ no magic!
+
+== Helidon MP
+
+Helidon MP is our MicroProfile implementation.
+
+https://microprofile.io[MicroProfile] is a platform definition that is familiar
+ to enterprise Java developers. It provides a declarative programming style that
+ is portable. It includes popular Java APIs such as `JAX-RS` and `CDI`.
+
+NOTE: Helidon MP is built on top of the Helidon libraries.

docs/src/main/docs/guides/01_overview.adoc

@@ -24,7 +24,6 @@
 
 [PILLARS]
 ====
-
 [CARD]
 .SE REST Web Service
 [link=guides/02_SE_REST_web-service.adoc]

docs/src/main/docs/sitegen.yaml

@@ -42,7 +42,7 @@ pages:
       - "**/*.adoc"
 backend:
     name: "vuetify"
-    homePage: "about/01_introduction.adoc"
+    homePage: "about/01_overview.adoc"
     releases:
         - "${project.version}"
     navigation:

docs/src/main/docs/tracing/01_tracing.adoc

@@ -0,0 +1,59 @@
+///////////////////////////////////////////////////////////////////////////////
+
+    Copyright (c) 2019 Oracle and/or its affiliates. All rights reserved.
+
+    Licensed 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
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    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.
+
+///////////////////////////////////////////////////////////////////////////////
+
+= Tracing
+:description: Helidon Tracing Support
+= :keywords: helidon, tracing
+
+== Tracing Support
+Helidon includes support for tracing through the `https://opentracing.io/[OpenTracing]` APIs.
+Tracing is integrated with WebServer and Security.
+
+Support for specific tracers is abstracted. Your application can depend on
+the abstraction layer and provide a specific tracer implementation as a Java
+`ServiceLoader` service.
+
+
+=== Maven Coordinates
+
+Declare the following dependency in your project to use the tracer abstraction:
+
+[source,xml,subs="verbatim,attributes"]
+.Tracer Abstraction
+----
+<dependency>
+    <groupId>io.helidon.tracing</groupId>
+    <artifactId>helidon-tracing</artifactId>
+</dependency>
+----
+
+=== Configuring Tracing
+
+To configure tracer with WebServer:
+
+[source,java]
+.Configuring OpenTracing `Tracer`
+----
+ServerConfiguration.builder()
+                   .tracer(TracerBuilder.create("my-application")                    // <1>
+                                 .collectorUri(URI.create("http://10.0.0.18:9411"))  // <2>
+                                 .build())
+                   .build()
+----
+<1> The name of the application (service) to associate with the tracing events
+<2> The endpoint for tracing events, specific to the tracer used, usually loaded from Config