add spring starter package for opencensus spring integration. (#1934)

* add spring starter package for opencensus spring integration.

* remove duplicate links.

* fix build error.

Author: rghetia

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## Unreleased
 - Make `StackdriverStatsExporter.unregister()` a public API.
+- Add support spring plugin for http servlet and AsyncRestTemplate.
+
 
 ## 0.22.1 - 2019-05-21
 - Increase the buffer size for the trace export batch to 2500 (previously it was 32).

all/build.gradle

@@ -22,6 +22,7 @@ def subprojects = [
         project(':opencensus-contrib-resource-util'),
         project(':opencensus-contrib-spring'),
         project(':opencensus-contrib-spring-sleuth-v1x'),
+        project(':opencensus-contrib-spring-starter'),
         project(':opencensus-contrib-zpages'),
         project(':opencensus-exporter-metrics-ocagent'),
         project(':opencensus-exporter-metrics-util'),
@@ -56,6 +57,7 @@ def subprojects_javadoc = [
         project(':opencensus-contrib-resource-util'),
         project(':opencensus-contrib-spring'),
         project(':opencensus-contrib-spring-sleuth-v1x'),
+        project(':opencensus-contrib-spring-starter'),
         project(':opencensus-contrib-zpages'),
         project(':opencensus-exporter-metrics-ocagent'),
         project(':opencensus-exporter-metrics-util'),

build.gradle

@@ -448,6 +448,7 @@ subprojects {
                  'opencensus-contrib-resource-util',
                  'opencensus-contrib-spring',
                  'opencensus-contrib-spring-sleuth-v1x',
+                 'opencensus-contrib-spring-starter',
                  'opencensus-contrib-zpages',
                  'opencensus-exporter-metrics-ocagent',
                  'opencensus-exporter-metrics-util',

contrib/spring_starter/README.md

@@ -0,0 +1,84 @@
+# OpenCensus Spring Starter
+[![Build Status][travis-image]][travis-url]
+[![Windows Build Status][appveyor-image]][appveyor-url]
+[![Maven Central][maven-image]][maven-url]
+
+The *OpenCensus Spring Starter for Java* is a starter package that includes
+packages required to enable tracing using opencensus when working with [Spring Web][spring-web-url].
+
+This version is compatible with [Spring Boot 2.0][spring-boot-2.0-url].
+
+## Servlet and AsyncRestTemplate Tracing
+
+Enable tracing on RestController (server side) and AysncRestTemplate (client side) by simply including opencensus-contrib-spring-starter in your dependencies and
+initializing exporter. It automatically traces your http request and collects stats associated with the
+request.
+
+It does require to register exporter and views.
+
+### Depedencies
+
+#### Maven
+
+```xml
+<dependencies>
+    <dependency>
+        <groupId>io.opencensus</groupId>
+        <artifactId>opencensus-contrib-spring-starter</artifactId>
+        <version>0.23.0</version>
+    </dependency>
+</dependencies>
+
+```
+
+#### Gradle
+```gradle
+dependencyManagement {
+    imports {
+        mavenBom "io.opencensus:opencensus-contrib-spring-starter:0.23.0"
+    }
+}
+dependencies {
+	compile 'io.opencensus:opencensus-contrib-spring:0.23.0'
+}
+```
+
+### Tracing Properties
+
+Optionally configure one or more Tracing Properties in application.properties file.
+
+
+#### PublicEndpoint
+
+If a servlet is serving publicEndpoints (untrusted boundary) then set this property to `true`. 
+When set to true incoming trace context is added as a parent link instead of as a parent.
+By default it is set to `false`. When set to `false` it uses incoming trace context as a parent.
+
+```
+opencensus.spring.trace.publicEndpoint = true
+```
+
+#### Propagation
+
+opencensus.spring.trace.propagation = TRACE_PROPAGATION_B3
+
+By default it is set to TRACE_PROPAGATION_TRACE_CONTEXT which uses [W3C Tracecontext](https://github.com/census-instrumentation/opencensus-java/blob/master/api/src/main/java/io/opencensus/trace/propagation/TextFormat.java)
+propagator to propagate trace context. To use [B3 format](https://github.com/census-instrumentation/opencensus-java/blob/master/impl_core/src/main/java/io/opencensus/implcore/trace/propagation/B3Format.java) 
+set the property to TRACE_PROPAGATION_B3
+
+```
+opencensus.spring.trace.propagation = TRACE_PROPAGATION_B3
+```
+
+#### Java Versions
+
+Java 6 or above is required for using this artifact.
+
+[travis-image]: https://travis-ci.org/census-instrumentation/opencensus-java.svg?branch=master
+[travis-url]: https://travis-ci.org/census-instrumentation/opencensus-java
+[appveyor-image]: https://ci.appveyor.com/api/projects/status/hxthmpkxar4jq4be/branch/master?svg=true
+[appveyor-url]: https://ci.appveyor.com/project/opencensusjavateam/opencensus-java/branch/master
+[maven-image]: https://maven-badges.herokuapp.com/maven-central/io.opencensus/opencensus-contrib-spring-starter/badge.svg
+[maven-url]: https://maven-badges.herokuapp.com/maven-central/io.opencensus/opencensus-contrib-spring-starter
+[spring-boot-2.0-url]: https://github.com/spring-projects/spring-boot/tree/2.0.x
+[spring-web-url]: https://github.com/spring-projects/spring-framework/tree/master/spring-web

contrib/spring_starter/build.gradle

@@ -0,0 +1,18 @@
+plugins {
+    id 'java'
+}
+
+description = 'OpenCensus Spring Cloud Starter'
+
+[compileJava, compileTestJava].each() {
+    it.sourceCompatibility = 1.6
+    it.targetCompatibility = 1.6
+}
+
+dependencies {
+    compile project(':opencensus-api'),
+            project(':opencensus-contrib-spring'),
+            project(':opencensus-impl')
+
+    signature "org.codehaus.mojo.signature:java16:+@signature"
+}

contrib/spring_starter/src/main/resources/META-INF/spring.provides

@@ -0,0 +1 @@
+provides: opencensus-contrib-spring

settings.gradle

@@ -37,6 +37,7 @@ include ":opencensus-contrib-log-correlation-stackdriver"
 include ":opencensus-contrib-resource-util"
 include ":opencensus-contrib-spring"
 include ":opencensus-contrib-spring-sleuth-v1x"
+include ":opencensus-contrib-spring-starter"
 include ":opencensus-contrib-zpages"
 
 project(':opencensus-all').projectDir = "$rootDir/all" as File
@@ -67,6 +68,7 @@ project(':opencensus-contrib-resource-util').projectDir = "$rootDir/contrib/reso
 project(':opencensus-contrib-spring').projectDir = "$rootDir/contrib/spring" as File
 project(':opencensus-contrib-spring-sleuth-v1x').projectDir =
         "$rootDir/contrib/spring_sleuth_v1x" as File
+project(':opencensus-contrib-spring-starter').projectDir = "$rootDir/contrib/spring_starter" as File
 project(':opencensus-contrib-zpages').projectDir = "$rootDir/contrib/zpages" as File
 project(':opencensus-exporter-metrics-ocagent').projectDir =
         "$rootDir/exporters/metrics/ocagent" as File