Add Cloud Function to intercept GitHub Webhooks to Mixpanel

server/analytics/build.gradle

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+// Drafted from https://github.com/GoogleCloudPlatform/java-docs-samples/blob/master/functions/helloworld/helloworld-gradle/build.gradle
+
+// Separate buildscript as this is the only file gcloud will see
+buildscript {
+  repositories {
+    jcenter()
+  }
+  dependencies {
+    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.4.20"
+  }
+}
+
+apply plugin: 'java'
+apply plugin: 'kotlin'
+
+repositories {
+  jcenter()
+  mavenCentral()
+}
+configurations {
+  invoker
+}
+
+dependencies {
+  compileOnly 'com.google.cloud.functions:functions-framework-api:1.0.1'
+
+  implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.4.20"
+  implementation 'com.mixpanel:mixpanel-java:1.4.4'
+  implementation 'com.google.code.gson:gson:2.8.6'
+
+  // These dependencies are only used by the tests.
+  testImplementation 'com.google.cloud.functions:functions-framework-api:1.0.1'
+  testImplementation 'junit:junit:4.13.1'
+  testImplementation 'org.assertj:assertj-core:3.18.0'
+  testImplementation 'com.squareup.okhttp3:mockwebserver:4.9.0'
+}

server/analytics/deploy.sh

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+gcloud functions deploy github-client-webhooks --entry-point com.jraska.devanalytics.github.GitHubEventsMixpanelFunction --runtime java11 --memory 256MB --trigger-http --allow-unauthenticated

server/analytics/src/main/java/com/jraska/devanalytics/github/GitHubEventsMixpanelFunction.kt

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+package com.jraska.devanalytics.github
+
+import com.google.cloud.functions.HttpFunction
+import com.google.cloud.functions.HttpRequest
+import com.google.cloud.functions.HttpResponse
+import com.jraska.devanalytics.github.model.Environment
+import com.jraska.devanalytics.github.report.GitHubEventMixpanelInterceptor
+
+class GitHubEventsMixpanelFunction : HttpFunction {
+  override fun service(gitHubWebHook: HttpRequest, response: HttpResponse) {
+    val interceptor = GitHubEventMixpanelInterceptor.create(Environment.create())
+
+    val event = interceptor.intercept(gitHubWebHook.reader)
+
+    response.writer.write("Event $event reported to Mixpanel")
+    response.setStatusCode(200)
+  }
+}

server/analytics/src/main/java/com/jraska/devanalytics/github/model/Environment.kt

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+package com.jraska.devanalytics.github.model
+
+const val MIXPANEL_KEY_ENV_VAR = "MIXPANEL_API_KEY"
+
+class Environment(
+  val mixpanelUrl: String?,
+  val mixpanelToken: String
+) {
+  companion object {
+    fun create(): Environment {
+      val mixpanelKey = System.getenv(MIXPANEL_KEY_ENV_VAR)
+      return Environment(null, mixpanelKey)
+    }
+  }
+}

server/analytics/src/main/java/com/jraska/devanalytics/github/model/EventReader.kt

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+package com.jraska.devanalytics.github.model
+
+import com.google.gson.Gson
+import java.io.BufferedReader
+
+class EventReader(
+  private val gson: Gson
+) {
+  fun parse(reader: BufferedReader): GitHubPrEvent {
+    val dto = gson.getAdapter(GitHubEventDto::class.java).fromJson(reader)
+
+    val action = dto.action
+    var comment = dto.comment?.body
+    if (comment == null && action == "opened") {
+      comment = dto.pullRequest?.body
+    }
+
+    if (comment == null && action == "created") {
+      comment = dto.review?.body
+    }
+
+    val login = dto.review?.user?.login ?: dto.sender.login
+
+    return GitHubPrEvent(
+      action,
+      login,
+      dto.pullRequest?.prUrl ?: dto.issue?.pullRequest?.prUrl ?: throw UnsupportedOperationException("PR url not found"),
+      dto.pullRequest?.number ?: dto.issue?.number ?: throw IllegalStateException("PR number not found"),
+      comment,
+      dto.review?.state
+    )
+  }
+
+  companion object {
+    fun create(): EventReader {
+      return EventReader(Gson())
+    }
+  }
+}

server/analytics/src/main/java/com/jraska/devanalytics/github/model/GitHubEventDto.kt

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+package com.jraska.devanalytics.github.model
+
+import com.google.gson.annotations.SerializedName
+
+class GitHubEventDto {
+  @SerializedName("action")
+  lateinit var action: String
+
+  @SerializedName("sender")
+  lateinit var sender: UserDto
+
+  @SerializedName("pull_request")
+  var pullRequest: PullRequestDto? = null
+
+  @SerializedName("issue")
+  var issue: IssueDto? = null
+
+  @SerializedName("comment")
+  var comment: CommentDto? = null
+
+  @SerializedName("review")
+  var review: ReviewDto? = null
+}
+
+class UserDto {
+  @SerializedName("login")
+  lateinit var login: String
+}
+
+class PullRequestDto {
+  @SerializedName("html_url")
+  lateinit var prUrl: String
+
+  @SerializedName("number")
+  var number: Int = 0
+
+  @SerializedName("body")
+  var body: String = ""
+}
+
+class IssueDto {
+  @SerializedName("pull_request")
+  var pullRequest: PullRequestDto? = null
+
+  @SerializedName("number")
+  var number: Int = 0
+}
+
+class CommentDto {
+  @SerializedName("body")
+  lateinit var body: String
+}
+
+class ReviewDto {
+  @SerializedName("user")
+  lateinit var user: UserDto
+
+  @SerializedName("state")
+  lateinit var state: String
+
+  @SerializedName("body")
+  lateinit var body: String
+}

server/analytics/src/main/java/com/jraska/devanalytics/github/model/GitHubPrEvent.kt

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+package com.jraska.devanalytics.github.model
+
+data class GitHubPrEvent(
+  val action: String,
+  val author: String,
+  val prUrl: String,
+  val prNumber: Int,
+  val comment: String?,
+  val state: String?
+)

server/analytics/src/main/java/com/jraska/devanalytics/github/report/GitHubEventMixpanelInterceptor.kt

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+package com.jraska.devanalytics.github.report
+
+import com.jraska.devanalytics.github.model.Environment
+import com.jraska.devanalytics.github.model.EventReader
+import com.jraska.devanalytics.github.model.GitHubPrEvent
+import java.io.BufferedReader
+
+class GitHubEventMixpanelInterceptor(
+  private val reporter: MixpanelReporter,
+  private val eventReader: EventReader
+) {
+  fun intercept(reader: BufferedReader): GitHubPrEvent {
+    val event = eventReader.parse(reader)
+    reporter.report(event)
+
+    return event
+  }
+
+  companion object {
+    fun create(environment: Environment): GitHubEventMixpanelInterceptor {
+      val reporter = MixpanelReporter.create(environment)
+      val eventReader = EventReader.create()
+
+      return GitHubEventMixpanelInterceptor(reporter, eventReader)
+    }
+  }
+}

server/analytics/src/main/java/com/jraska/devanalytics/github/report/MixpanelReporter.kt

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+package com.jraska.devanalytics.github.report
+
+import com.jraska.devanalytics.github.model.Environment
+import com.jraska.devanalytics.github.model.GitHubPrEvent
+import com.mixpanel.mixpanelapi.ClientDelivery
+import com.mixpanel.mixpanelapi.MessageBuilder
+import com.mixpanel.mixpanelapi.MixpanelAPI
+import org.json.JSONObject
+
+class MixpanelReporter(
+  private val api: MixpanelAPI,
+  private val apiKey: String
+) {
+  fun report(event: GitHubPrEvent) {
+    val delivery = ClientDelivery()
+
+    val properties = convertEvent(event)
+    val mixpanelEvent = MessageBuilder(apiKey)
+      .event(SINGLE_NAME_FOR_ONE_USER, "PR Event", JSONObject(properties))
+
+    delivery.addMessage(mixpanelEvent)
+
+    api.deliver(delivery)
+  }
+
+  private fun convertEvent(event: GitHubPrEvent): Map<String, Any?> {
+    return mapOf(
+      "action" to event.action,
+      "prUrl" to event.prUrl,
+      "author" to event.author,
+      "comment" to event.comment,
+      "state" to event.state,
+      "prNumber" to event.prNumber
+    ).filter { it.value != null }
+  }
+
+  companion object {
+    fun create(environment: Environment): MixpanelReporter {
+      val mixpanelApi = if (environment.mixpanelUrl == null) {
+        MixpanelAPI()
+      } else {
+        MixpanelAPI(environment.mixpanelUrl, environment.mixpanelUrl)
+      }
+
+      return MixpanelReporter(mixpanelApi, environment.mixpanelToken)
+    }
+
+    private val SINGLE_NAME_FOR_ONE_USER = "GitHub PRs Reporter"
+  }
+}

server/analytics/src/test/java/com/jraska/devanalytics/github/EventReaderTest.kt

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+package com.jraska.devanalytics.github
+
+import com.jraska.devanalytics.github.model.EventReader
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.Test
+import java.io.BufferedReader
+import java.io.File
+
+class EventReaderTest {
+  @Test
+  fun canReadPrOpenEvent() {
+    val jsonReader = json("response/pr_open.json")
+
+    val event = EventReader.create().parse(jsonReader)
+
+    assertThat(event.action).isEqualTo("opened")
+    assertThat(event.author).isEqualTo("Codertocat")
+    assertThat(event.prUrl).isEqualTo("https://github.com/Codertocat/Hello-World/pull/2")
+    assertThat(event.prNumber).isEqualTo(2)
+    assertThat(event.comment).isEqualTo("This is a pretty simple change that we need to pull into master.")
+    assertThat(event.state).isNull()
+  }
+
+  @Test
+  fun canReadPrCommentEvent() {
+    val jsonReader = json("response/pr_comment.json")
+
+    val event = EventReader.create().parse(jsonReader)
+
+    assertThat(event.action).isEqualTo("created")
+    assertThat(event.author).isEqualTo("jraska")
+    assertThat(event.prUrl).isEqualTo("https://github.com/jraska/github-client/pull/353")
+    assertThat(event.prNumber).isEqualTo(353)
+    assertThat(event.comment).isEqualTo("Another test comment")
+  }
+
+  @Test
+  fun canReadPrReviewRequestedEvent() {
+    val jsonReader = json("response/review_requested.json")
+
+    val event = EventReader.create().parse(jsonReader)
+
+    assertThat(event.action).isEqualTo("review_requested")
+    assertThat(event.author).isEqualTo("jraska")
+    assertThat(event.prUrl).isEqualTo("https://github.com/jraska/github-client/pull/353")
+    assertThat(event.prNumber).isEqualTo(353)
+    assertThat(event.comment).isNull()
+  }
+
+  @Test
+  fun canReadPrCommentDeletedEvent() {
+    val jsonReader = json("response/comment_deleted.json")
+
+    val event = EventReader.create().parse(jsonReader)
+
+    assertThat(event.action).isEqualTo("deleted")
+    assertThat(event.author).isEqualTo("jraska")
+    assertThat(event.prUrl).isEqualTo("https://github.com/jraska/github-client/pull/353")
+    assertThat(event.prNumber).isEqualTo(353)
+    assertThat(event.comment).isEqualTo("Test comment for webhook")
+  }
+
+  @Test
+  fun canReadReviewCreatedDeletedEvent() {
+    val jsonReader = json("response/review_created.json")
+
+    val event = EventReader.create().parse(jsonReader)
+
+    assertThat(event.action).isEqualTo("created")
+    assertThat(event.author).isEqualTo("mikehardy")
+    assertThat(event.prUrl).isEqualTo("https://github.com/ankidroid/Anki-Android/pull/7765")
+    assertThat(event.prNumber).isEqualTo(7765)
+    assertThat(event.comment).isEqualTo("Yeah this all seems fine, including the default setting\r\n\r\n> I'm bad at days off\r\n\r\nhahaha you and me both, I suppose as long as it's fun, is it a day on?")
+    assertThat(event.state).isEqualTo("approved")
+  }
+
+  companion object {
+    fun json(path: String): BufferedReader {
+      val uri = this.javaClass.classLoader.getResource(path)
+      val file = File(uri!!.path)
+      return file.bufferedReader()
+    }
+  }
+}

server/analytics/src/test/java/com/jraska/devanalytics/github/report/GitHubEventMixpanelInterceptorTest.kt

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+package com.jraska.devanalytics.github.report
+
+import com.jraska.devanalytics.github.EventReaderTest
+import com.jraska.devanalytics.github.model.Environment
+import okhttp3.mockwebserver.MockResponse
+import okhttp3.mockwebserver.MockWebServer
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.Rule
+import org.junit.Test
+
+class GitHubEventMixpanelInterceptorTest {
+  @get:Rule
+  val mockWebServer = MockWebServer()
+
+  @Test
+  fun reportsToFakeServer() {
+    val fakeEnvironment = Environment(mockWebServer.url("/mixpanel/").toString(), "fakeToken")
+    val interceptor = GitHubEventMixpanelInterceptor.create(fakeEnvironment)
+
+    mockWebServer.enqueue(MockResponse().setResponseCode(200).setBody("1"))
+
+    val event = interceptor.intercept(EventReaderTest.json("response/pr_comment.json"))
+
+    assertThat(event.action).isEqualTo("created")
+    assertThat(event.author).isEqualTo("jraska")
+    assertThat(event.prUrl).isEqualTo("https://github.com/jraska/github-client/pull/353")
+    assertThat(event.prNumber).isEqualTo(353)
+    assertThat(event.comment).isEqualTo("Another test comment")
+  }
+}