Add version to jar manifest and read at runtime for SDK version header (

#22)

Add version to the jar manifest and read from that to send the SDK version header

https://docs.gradle.org/current/samples/sample_building_kotlin_libraries.html#customize_the_library_jar

https://stackoverflow.com/a/43065467

To avoid unnecessarily reading from the manifest file, we store the value in a companion object which
should have the effect of making it a singleton.

An alternative using java properties was considered based on https://stackoverflow.com/a/70088083, but
the jar manifest seemed more appropriate

inngest-core/build.gradle.kts

@@ -1,4 +1,5 @@
 description = "Inngest SDK"
+version = "0.0.1-SNAPSHOT"
 
 plugins { id("org.jetbrains.kotlin.jvm") version "1.9.10" }
 
@@ -17,6 +18,17 @@ dependencies {
     testImplementation(kotlin("test"))
 }
 
+tasks.jar {
+    manifest {
+        attributes(
+            mapOf(
+                "Implementation-Title" to project.name,
+                "Implementation-Version" to project.version,
+            ),
+        )
+    }
+}
+
 tasks.named<Test>("test") {
     // Use JUnit Platform for unit tests.
     useJUnitPlatform()

inngest-core/src/main/kotlin/com/inngest/Comm.kt

@@ -50,7 +50,7 @@ class CommHandler(val functions: HashMap<String, InngestFunction>) {
         return mapOf(
             "Content-Type" to "application/json",
             // TODO - Get this from the build
-            "x-inngest-sdk" to "inngest-kt:v0.0.1",
+            "x-inngest-sdk" to "inngest-kt:${Version.getVersion()}",
             // TODO - Pull this from options
             "x-inngest-framework" to "ktor",
         )
@@ -123,7 +123,7 @@ class CommHandler(val functions: HashMap<String, InngestFunction>) {
                 framework = "ktor",
                 sdk = "kotlin",
                 url = "http://localhost:8080/api/inngest",
-                v = "0.0.1",
+                v = Version.getVersion(),
                 functions = getFunctionConfigs(),
             )
         val jsonRequestBody = Klaxon().toJsonString(requestPayload)
@@ -163,7 +163,7 @@ class CommHandler(val functions: HashMap<String, InngestFunction>) {
                 framework = "ktor",
                 sdk = "kotlin",
                 url = "http://localhost:8080/api/inngest",
-                v = "0.0.1",
+                v = Version.getVersion(),
                 functions = getFunctionConfigs(),
             )
         return Klaxon().toJsonString(requestPayload)

inngest-core/src/main/kotlin/com/inngest/Version.kt

@@ -0,0 +1,9 @@
+package com.inngest
+
+class Version() {
+    companion object {
+        private val version: String = Version::class.java.getPackage().implementationVersion
+
+        fun getVersion(): String = version
+    }
+}