Demonstrate template versions

Change-Id: I4a36b14ed10b52da3443f5074430841465a0d3e5

Author: kroikie

config/README.md

@@ -1,7 +1,7 @@
 Firebase Remote Config REST API Java Quickstart
 ===============================================
 
-The Firebase Remote Config Java quickstart app demonstrates retrieving and
+The [Firebase Remote Config](https://firebase.google.com/docs/remote-config/) Java quickstart app demonstrates retrieving and
 updating the Firebase Remote Config template.
 
 Introduction
@@ -21,10 +21,11 @@ Getting started
 Run
 ---
 
-- From the `config` directory run `./gradlew run -Paction=get` to retrieve the template.
-  - The returned template is stored in a file named `config.json`.
-  - Note the Etag printed to the console you will need to use it when publishing template updates.
-- Update the template.
+- Get active template
+  - From the `config` directory run `./gradlew run -Paction=get` to retrieve the template.
+    - The returned template is stored in a file named `config.json`.
+    - Note the ETag printed to the console you will need to use it when publishing template updates.
+- Update the template
   - If your template already has parameters, adjust one or more of the values.
   - If your template is empty, update it to look like this:
 
@@ -58,28 +59,50 @@ Run
           }
         }
 
-- From the `config` directory run `./gradlew run -Paction=publish -Petag='<LATEST_ETAG>'` to update the template.
-  - Be sure to set the etag to the one that was last printed in the console.
-- Confirm in the console that the template has been updated.
-  - At this point mobile clients can fetch the updated values.
+  - From the `config` directory run `./gradlew run -Paction=publish -Petag='<LATEST_ETAG>'` to update the template.
+    - Be sure to set the etag to the one that was last printed in the console.
+  - Confirm in the console that the template has been updated.
+    - At this point mobile clients can fetch the updated values.
+- View existing versions
+  - From the `config` directory run `./gradlew run -Paction=versions` to print the
+    last 5 template versions.
+- Roll back to an existing template
+  - From the `config` directory run `./gradlew run -Paction=rollback -Pversion=<TEMPLATE_VERSION_NUMBER>` to
+    activate the template with the matching version number.
 
 Best practices
 --------------
 
 This section provides some additional information about how the Remote Config
 REST API should be used when retrieving and updating templates.
 
-### Etags ###
+### [Versions](https://firebase.google.com/docs/remote-config/templates) ###
 
-Each time the Remote Config template it retrieved an Etag is included. This Etag is a
+Each time you update parameters, {{remote_config}} creates a
+new versioned {{remote_config}} template and stores the previous template as
+a version that you can retrieve or roll back to as needed.
+
+All non-active versions expire and are removed if they are older than 90 days or if
+there are more than 300 newer template versions. Since template versions expire, any
+versions that need to be retrieved later on should be persisted externally.
+
+Use the `listVersions` [query parameters](https://firebase.google.com/docs/reference/remote-config/rest/v1/projects.remoteConfig/listVersions#query-parameters)
+to filter the versions that are returned.
+
+### ETags ###
+
+Each time the Remote Config template it retrieved an ETag is included. This ETag is a
 unique identifier of the current template on the server. When submitting updates
-to the template you must include the latest Etag to ensure that your updates are consistent.
+to the template you must include the latest ETag to ensure that your updates are consistent.
 
 In the event that you want to completely overwrite the server's template use
-an Etag of "\*". Use this with caution since this operation cannot be undone.
+an ETag of "\*". Use this with caution since this operation cannot be undone.
+
+**NOTE:** To get the ETag your request must accept the gzip encoding. Add the header
+`Accept-Encoding: gzip` to receive the ETag in the response header `ETag`.
 
 Support
 -------
 
-- [Stack Overflow](https://stackoverflow.com/questions/tagged/firebase-cloud-messaging)
+- [Stack Overflow](https://stackoverflow.com/questions/tagged/firebase-remote-config)
 - [Firebase Support](https://firebase.google.com/support/)

config/build.gradle

@@ -15,6 +15,9 @@ run {
     if (project.hasProperty("etag")) {
         args = args << "${etag}"
     }
+    if (project.hasProperty("version") && !project.version.equals("unspecified")) {
+        args = args << "${version}"
+    }
     standardInput = System.in
 }
 

config/gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-3.3-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.9-bin.zip

config/src/main/java/com/google/firebase/samples/config/Configure.java

@@ -4,7 +4,9 @@
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
+
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
@@ -25,7 +27,7 @@
  */
 public class Configure {
 
-  private final static String PROJECT_ID = "<YOUR-PROJECT-ID>";
+  private final static String PROJECT_ID = "PROJECT_ID";
   private final static String BASE_URL = "https://firebaseremoteconfig.googleapis.com";
   private final static String REMOTE_CONFIG_ENDPOINT = "/v1/projects/" + PROJECT_ID + "/remoteConfig";
   private final static String REMOTE_CONFIG_SCOPE = "https://www.googleapis.com/auth/firebase.remoteconfig";
@@ -51,7 +53,7 @@ private static String getAccessToken() throws IOException {
    * @throws IOException
    */
   private static void getTemplate() throws IOException {
-    HttpURLConnection httpURLConnection = getCommonConnection();
+    HttpURLConnection httpURLConnection = getCommonConnection(BASE_URL + REMOTE_CONFIG_ENDPOINT);
     httpURLConnection.setRequestMethod("GET");
     httpURLConnection.setRequestProperty("Accept-Encoding", "gzip");
 
@@ -83,6 +85,64 @@ private static void getTemplate() throws IOException {
 
   }
 
+  /**
+   * Print the last 5 available Firebase Remote Config template metadata from the server.
+   *
+   * @throws IOException
+   */
+  private static void getVersions() throws IOException {
+    HttpURLConnection httpURLConnection = getCommonConnection(BASE_URL + REMOTE_CONFIG_ENDPOINT
+            + ":listVersions?pageSize=5");
+    httpURLConnection.setRequestMethod("GET");
+
+    int code = httpURLConnection.getResponseCode();
+    if (code == 200) {
+      String versions = inputstreamToPrettyString(httpURLConnection.getInputStream());
+
+      System.out.println("Versions:");
+      System.out.println(versions);
+    } else {
+      System.out.println(inputstreamToString(httpURLConnection.getErrorStream()));
+    }
+  }
+
+  /**
+   * Roll back to an available version of Firebase Remote Config template.
+   *
+   * @param version The version to roll back to.
+   *
+   * @throws IOException
+   */
+  private static void rollback(int version) throws IOException {
+    HttpURLConnection httpURLConnection = getCommonConnection(BASE_URL + REMOTE_CONFIG_ENDPOINT
+            + ":rollback");
+    httpURLConnection.setDoOutput(true);
+    httpURLConnection.setRequestMethod("POST");
+    httpURLConnection.setRequestProperty("Accept-Encoding", "gzip");
+
+    JsonObject jsonObject = new JsonObject();
+    jsonObject.addProperty("version_number", version);
+
+    OutputStreamWriter outputStreamWriter = new OutputStreamWriter(httpURLConnection.getOutputStream());
+    outputStreamWriter.write(jsonObject.toString());
+    outputStreamWriter.flush();
+    outputStreamWriter.close();
+
+    int code = httpURLConnection.getResponseCode();
+    if (code == 200) {
+      System.out.println("Rolled back to: "  + version);
+      InputStream inputStream = new GZIPInputStream(httpURLConnection.getInputStream());
+      System.out.println(inputstreamToPrettyString(inputStream));
+
+      // Print ETag
+      String etag = httpURLConnection.getHeaderField("ETag");
+      System.out.println("ETag from server: " + etag);
+    } else {
+      System.out.println("Error:");
+      System.out.println(inputstreamToString(httpURLConnection.getErrorStream()));
+    }
+  }
+
   /**
    * Publish local template to Firebase server.
    *
@@ -100,7 +160,7 @@ private static void publishTemplate(String etag) throws IOException {
     }
 
     System.out.println("Publishing template...");
-    HttpURLConnection httpURLConnection = getCommonConnection();
+    HttpURLConnection httpURLConnection = getCommonConnection(BASE_URL + REMOTE_CONFIG_ENDPOINT);
     httpURLConnection.setDoOutput(true);
     httpURLConnection.setRequestMethod("PUT");
     httpURLConnection.setRequestProperty("If-Match", etag);
@@ -140,6 +200,26 @@ private static String readConfig() throws FileNotFoundException {
     return stringBuilder.toString();
   }
 
+  /**
+   * Format content from an InputStream as pretty JSON.
+   *
+   * @param inputStream Content to be formatted.
+   * @return Pretty JSON formatted string.
+   *
+   * @throws IOException
+   */
+  private static String inputstreamToPrettyString(InputStream inputStream) throws IOException {
+    String response = inputstreamToString(inputStream);
+
+    JsonParser jsonParser = new JsonParser();
+    JsonElement jsonElement = jsonParser.parse(response);
+
+    Gson gson = new GsonBuilder().setPrettyPrinting().disableHtmlEscaping().create();
+    String jsonStr = gson.toJson(jsonElement);
+
+    return jsonStr;
+  }
+
   /**
    * Read contents of InputStream into String.
    *
@@ -162,8 +242,8 @@ private static String inputstreamToString(InputStream inputStream) throws IOExce
    * @return Base HttpURLConnection.
    * @throws IOException
    */
-  private static HttpURLConnection getCommonConnection() throws IOException {
-    URL url = new URL(BASE_URL + REMOTE_CONFIG_ENDPOINT);
+  private static HttpURLConnection getCommonConnection(String endpoint) throws IOException {
+    URL url = new URL(endpoint);
     HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
     httpURLConnection.setRequestProperty("Authorization", "Bearer " + getAccessToken());
     httpURLConnection.setRequestProperty("Content-Type", "application/json; UTF-8");
@@ -173,14 +253,22 @@ private static HttpURLConnection getCommonConnection() throws IOException {
   public static void main(String[] args) throws IOException {
     if (args.length > 1 && args[0].equals("publish")) {
       publishTemplate(args[1]);
-    } else if (args.length == 1 && args[0].equals("get")){
+    } else if (args.length == 1 && args[0].equals("get")) {
       getTemplate();
+    } else if (args.length == 1 && args[0].equals("versions")) {
+      getVersions();
+    } else if (args.length > 1 && args[0].equals("rollback")) {
+      rollback(Integer.parseInt(args[1]));
     } else {
       System.err.println("Invalid request. Please use one of the following commands:");
       // To get the current template from the server.
       System.err.println("./gradlew run -Paction=get");
       // To publish the template in config.json to the server.
-      System.err.println("./gradlew run -Paction=publish -Petag='LATEST_ETAG'");
+      System.err.println("./gradlew run -Paction=publish -Petag='<LATEST_ETAG>'");
+      // To get the available template versions from the server.
+      System.err.println("./gradlew run -Paction=versions");
+      // To roll back to a particular version.
+      System.err.println("./gradlew run -Paction=rollback -Pversion=<TEMPLATE_VERSION_NUMBER>");
     }
   }