From 7ebe0688e0ba2d59e586740abbf13949da152713 Mon Sep 17 00:00:00 2001
From: Mitsunori Komatsu <komamitsu@gmail.com>
Date: Thu, 3 Jun 2021 18:28:52 +0900
Subject: [PATCH] Enable `startFromHead` of EcsClient for `nextToken` (#1593)

---
 .../io/digdag/standards/command/EcsCommandExecutor.java  | 9 +++++++++
 .../digdag/standards/command/ecs/DefaultEcsClient.java   | 2 ++
 2 files changed, 11 insertions(+)

diff --git a/digdag-standards/src/main/java/io/digdag/standards/command/EcsCommandExecutor.java b/digdag-standards/src/main/java/io/digdag/standards/command/EcsCommandExecutor.java
index a639ece986..cdef64aa9a 100644
--- a/digdag-standards/src/main/java/io/digdag/standards/command/EcsCommandExecutor.java
+++ b/digdag-standards/src/main/java/io/digdag/standards/command/EcsCommandExecutor.java
@@ -60,6 +60,7 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 
 public class EcsCommandExecutor
@@ -329,6 +330,14 @@ CommandStatus createNextCommandStatus(
                 if (previousExecutorStatus.get("logging_finished_at") != null) {
                     break;
                 }
+                try {
+                    // Just to avoid DOS attack to ECS endpoint
+                    TimeUnit.SECONDS.sleep(2);
+                }
+                catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                    throw new RuntimeException(e);
+                }
             }
             while (Instant.now().getEpochSecond() < timeout);
 
diff --git a/digdag-standards/src/main/java/io/digdag/standards/command/ecs/DefaultEcsClient.java b/digdag-standards/src/main/java/io/digdag/standards/command/ecs/DefaultEcsClient.java
index ee8fa3270e..0c054e78f4 100644
--- a/digdag-standards/src/main/java/io/digdag/standards/command/ecs/DefaultEcsClient.java
+++ b/digdag-standards/src/main/java/io/digdag/standards/command/ecs/DefaultEcsClient.java
@@ -270,6 +270,8 @@ public GetLogEventsResult getLog(
             final Optional<String> nextToken)
     {
         final GetLogEventsRequest request = new GetLogEventsRequest()
+                // This should be true when using `nextToken`. See the doc for details.
+                .withStartFromHead(true)
                 .withLogGroupName(groupName)
                 .withLogStreamName(streamName);
         if (nextToken.isPresent()) {