point examples at the snapshot version of stable modules (#2993)

* point examples at the snapshot version of stable modules, to highlight any breaking changes before they are released.

* parameterize the version that the examples are built against.

.github/workflows/pr-examples-build.yml

@@ -35,6 +35,7 @@ jobs:
       - uses: burrunan/gradle-cache-action@v1.8
         with:
           remote-build-cache-proxy-enabled: false
-          arguments: clean check shadowJar
+          ## todo: how to make sure these are kept up to date, so we always build against the latest snapshots for stable modules
+          arguments: -Pio.opentelemetry.version=1.1.0-SNAPSHOT clean check shadowJar
           build-root-directory: examples
       - run: java -cp examples/sdk-usage/build/libs/opentelemetry-examples-sdk-usage-0.1.0-SNAPSHOT-all.jar io.opentelemetry.sdk.example.ConfigureSpanProcessorExample

examples/build.gradle

@@ -3,6 +3,8 @@ plugins {
     id "com.github.johnrengelman.shadow" apply false
 }
 
+println("Building against OpenTelemetry version: ${project.properties["io.opentelemetry.version"]}")
+
 subprojects {
     apply plugin: 'eclipse'
     apply plugin: 'java'
@@ -15,8 +17,10 @@ subprojects {
     version = "0.1.0-SNAPSHOT"
 
     ext {
-        openTelemetryVersion = "1.0.0"
-        openTelemetryAlphaVersion = "1.0.0-alpha"
+        //these versions are defined in gradle.properties
+        openTelemetryVersion = project.properties["io.opentelemetry.version"]
+        openTelemetryAlphaVersion = project.properties["io.opentelemetry.version.alpha"]
+
         grpcVersion = '1.34.1'
         protobufVersion = '3.11.4'
         protocVersion = protobufVersion

examples/gradle.properties

@@ -0,0 +1,2 @@
+io.opentelemetry.version=1.0.0
+io.opentelemetry.version.alpha=1.0.0-alpha