Adds JWT refresh to http example. (#906)

Author: gguuss

iot/api-client/http_example/src/main/java/com/google/cloud/iot/examples/HttpExample.java

@@ -145,6 +145,7 @@ public static void main(String[] args) throws Exception {
 
  // Create the corresponding JWT depending on the selected algorithm.
  String token;
+ DateTime iat = new DateTime();
  if (options.algorithm.equals("RS256")) {
  token = createJwtRsa(options.projectId, options.privateKeyFile);
  } else if (options.algorithm.equals("ES256")) {
@@ -154,15 +155,28 @@ public static void main(String[] args) throws Exception {
  "Invalid algorithm " + options.algorithm + ". Should be one of 'RS256' or 'ES256'.");
  }
 
+ String urlPath = String.format("%s/%s/", options.httpBridgeAddress, options.apiVersion);
+ System.out.format("Using URL: '%s'\n", urlPath);
+
  // Publish numMessages messages to the HTTP bridge.
  for (int i = 1; i <= options.numMessages; ++i) {
  String payload = String.format("%s/%s-payload-%d", options.registryId, options.deviceId, i);
  System.out.format(
  "Publishing %s message %d/%d: '%s'\n",
  options.messageType, i, options.numMessages, payload);
 
- String urlPath = String.format("%s/%s/", options.httpBridgeAddress, options.apiVersion);
- System.out.format("Using URL: '%s'\n", urlPath);
+ // Refresh the authentication token if the token has expired.
+ long secsSinceRefresh = ((new DateTime()).getMillis() - iat.getMillis()) / 1000;
+ if (secsSinceRefresh > (options.tokenExpMins * 60)) {
+ System.out.format("\tRefreshing token after: %d seconds\n", secsSinceRefresh);
+ iat = new DateTime();
+
+ if (options.algorithm.equals("RS256")) {
+ token = createJwtRsa(options.projectId, options.privateKeyFile);
+ } else if (options.algorithm.equals("ES256")) {
+ token = createJwtEs(options.projectId, options.privateKeyFile);
+ }
+ }
 
  publishMessage(payload, urlPath, options.messageType, token, options.projectId,
  options.cloudRegion, options.registryId, options.deviceId);

iot/api-client/http_example/src/main/java/com/google/cloud/iot/examples/HttpExampleOptions.java

@@ -30,6 +30,7 @@ public class HttpExampleOptions {
  String algorithm;
  String cloudRegion = "us-central1";
  int numMessages = 100;
+ int tokenExpMins = 20;
  String httpBridgeAddress = "https://cloudiot-device.googleapis.com";
  String apiVersion = "v1beta1";
  String messageType = "event";
@@ -94,6 +95,13 @@ public static HttpExampleOptions fromFlags(String[] args) {
  .hasArg()
  .desc("Number of messages to publish.")
  .build());
+ options.addOption(
+ Option.builder()
+ .type(Number.class)
+ .longOpt("token_exp_minutes")
+ .hasArg()
+ .desc("Minutes to JWT token refresh (token expiration time).")
+ .build());
  options.addOption(
  Option.builder()
  .type(String.class)
@@ -133,6 +141,10 @@ public static HttpExampleOptions fromFlags(String[] args) {
  if (commandLine.hasOption("num_messages")) {
  res.numMessages = ((Number) commandLine.getParsedOptionValue("num_messages")).intValue();
  }
+ if (commandLine.hasOption("token_exp_minutes")) {
+ res.tokenExpMins =
+ ((Number) commandLine.getParsedOptionValue("token_exp_minutes")).intValue();
+ }
  if (commandLine.hasOption("http_bridge_address")) {
  res.httpBridgeAddress = commandLine.getOptionValue("http_bridge_address");
  }