imply-cheddar commented on code in PR #14239:
URL: https://github.com/apache/druid/pull/14239#discussion_r1190490704
##########
indexing-service/src/main/java/org/apache/druid/indexing/common/TaskStorageDirTracker.java:
##########
@@ -24,91 +24,202 @@
import org.apache.druid.indexing.worker.config.WorkerConfig;
import org.apache.druid.java.util.common.FileUtils;
import org.apache.druid.java.util.common.ISE;
+import org.apache.druid.java.util.common.StringUtils;
import org.apache.druid.java.util.common.lifecycle.LifecycleStart;
import javax.annotation.Nullable;
import java.io.File;
import java.io.IOException;
+import java.util.Arrays;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;
+/**
+ * Used to pick storage slots for tasks when run from the middle manager.
+ */
public class TaskStorageDirTracker
{
public static TaskStorageDirTracker fromConfigs(WorkerConfig workerConfig,
TaskConfig taskConfig)
{
+ final List<File> baseTaskDirs;
if (workerConfig == null) {
- return new
TaskStorageDirTracker(ImmutableList.of(taskConfig.getBaseTaskDir()));
+ baseTaskDirs = ImmutableList.of(taskConfig.getBaseTaskDir());
} else {
final List<String> basePaths = workerConfig.getBaseTaskDirs();
if (basePaths == null) {
- return new
TaskStorageDirTracker(ImmutableList.of(taskConfig.getBaseTaskDir()));
+ baseTaskDirs = ImmutableList.of(taskConfig.getBaseTaskDir());
+ } else {
+ baseTaskDirs =
basePaths.stream().map(File::new).collect(Collectors.toList());
}
- return new TaskStorageDirTracker(
- basePaths.stream().map(File::new).collect(Collectors.toList())
- );
}
+
+ return fromBaseDirs(baseTaskDirs, workerConfig.getCapacity(),
workerConfig.getBaseTaskDirSize());
+ }
+
+ public static TaskStorageDirTracker fromBaseDirs(List<File> baseTaskDirs,
int numSlots, long dirSize)
+ {
+ int slotsPerBaseTaskDir = Math.max(1, numSlots / baseTaskDirs.size());
+ if (numSlots % baseTaskDirs.size() > 0) {
+ // We have to add an extra slot per location if they do not evenly divide
+ ++slotsPerBaseTaskDir;
+ }
+ long sizePerSlot = dirSize / slotsPerBaseTaskDir;
+
+ StorageSlot[] slots = new StorageSlot[numSlots];
+ for (int i = 0; i < numSlots; ++i) {
+ final int whichDir = i % baseTaskDirs.size();
+ final int dirUsageCount = i / baseTaskDirs.size();
+ final File slotDirectory = new File(baseTaskDirs.get(whichDir),
StringUtils.format("slot%d", dirUsageCount));
+ slots[i] = new StorageSlot(slotDirectory, sizePerSlot);
+ }
+
+ return new TaskStorageDirTracker(baseTaskDirs, slots);
}
+ /**
+ * The base task dirs, this field exists primarily for compatibility with
scheduling that was done
+ * before TaskStorageDirTracker was introduced. All of the tasks were just
splatted together
+ * into one directory. If we want to be able to restore the tasks, we need
to be able to find them
+ * at the old locations and that is why this exists.
+ */
private final File[] baseTaskDirs;
- // Initialize to a negative number because it ensures that we can handle the
overflow-rollover case
+
+ /**
+ * These are slots pre-divided to keep disk sizing considerations aligned.
The normal operation of this
+ * class is to round-robin across these slots.
+ */
+ private final StorageSlot[] slots;
+
+ /**
+ * A counter used to simplify round-robin allocation. We initialize it to a
negative value because it
+ * simplifies testing/ensuring that we can handle overflow-rollover of the
integer
+ */
private final AtomicInteger iterationCounter = new
AtomicInteger(Integer.MIN_VALUE);
- public TaskStorageDirTracker(List<File> baseTaskDirs)
+ public TaskStorageDirTracker(List<File> baseTaskDirs, StorageSlot[] slots)
{
this.baseTaskDirs = baseTaskDirs.toArray(new File[0]);
+ this.slots = slots;
}
@LifecycleStart
public void ensureDirectories()
{
- for (File baseTaskDir : baseTaskDirs) {
- if (!baseTaskDir.exists()) {
+ for (StorageSlot slot : slots) {
+ if (!slot.getDirectory().exists()) {
try {
- FileUtils.mkdirp(baseTaskDir);
+ FileUtils.mkdirp(slot.getDirectory());
}
catch (IOException e) {
throw new ISE(
e,
- "base task directory [%s] likely does not exist, please ensure
it exists and the user has permissions.",
- baseTaskDir
+ "directory for slot [%s] likely does not exist, please ensure it
exists and the user has permissions.",
+ slot
);
}
}
}
}
- public File pickBaseDir(String taskId)
+ public synchronized StorageSlot pickStorageSlot(String taskId)
{
- if (baseTaskDirs.length == 1) {
- return baseTaskDirs[0];
+ // if the task directory already exists, we want to give it precedence, so
check.
+ for (StorageSlot slot : slots) {
+ if (slot.runningTaskId != null && slot.runningTaskId.equals(taskId)) {
+ return slot;
+ }
}
- // if the task directory already exists, we want to give it precedence, so
check.
- for (File baseTaskDir : baseTaskDirs) {
- if (new File(baseTaskDir, taskId).exists()) {
- return baseTaskDir;
+ // if it doesn't exist, pick one round-robin and ensure it is unused.
+ for (int i = 0; i < slots.length; ++i) {
+ // This can be negative, so abs() it.
+ final int currIncrement = Math.abs(iterationCounter.getAndIncrement() %
slots.length);
+ final StorageSlot candidateSlot = slots[currIncrement % slots.length];
+ if (candidateSlot.runningTaskId != null) {
+ continue;
}
+ candidateSlot.runningTaskId = taskId;
+ return candidateSlot;
}
+ throw new ISE("Unable to pick a free slot, this should never happen, slot
status [%s].", Arrays.toString(slots));
+ }
- // if it doesn't exist, pick one round-robin and return. This can be
negative, so abs() it
- final int currIncrement = Math.abs(iterationCounter.getAndIncrement() %
baseTaskDirs.length);
- return baseTaskDirs[currIncrement % baseTaskDirs.length];
+ public synchronized void returnStorageSlot(StorageSlot slot)
+ {
+ slot.runningTaskId = null;
}
@Nullable
- public File findExistingTaskDir(String taskId)
+ public synchronized File findExistingTaskDir(String taskId)
{
+ File candidateLocation = null;
if (baseTaskDirs.length == 1) {
- return new File(baseTaskDirs[0], taskId);
+ candidateLocation = new File(baseTaskDirs[0], taskId);
+ } else {
+ for (File baseTaskDir : baseTaskDirs) {
+ File maybeExists = new File(baseTaskDir, taskId);
+ if (maybeExists.exists()) {
+ candidateLocation = maybeExists;
+ break;
+ }
+ }
}
- for (File baseTaskDir : baseTaskDirs) {
- final File candidateLocation = new File(baseTaskDir, taskId);
- if (candidateLocation.exists()) {
- return candidateLocation;
+ if (candidateLocation != null && candidateLocation.exists()) {
+ // task exists at old location, relocate to a "good" slot location and
return that.
+ final StorageSlot taskSlot = pickStorageSlot(taskId);
+ final File pickedLocation = new File(taskSlot.getDirectory(), taskId);
+ if (candidateLocation.renameTo(pickedLocation)) {
+ taskSlot.runningTaskId = taskId;
+ return pickedLocation;
+ } else {
+ throw new ISE("Unable to relocate task ([%s] -> [%s])",
candidateLocation, pickedLocation);
Review Comment:
Good catch, I need tests that cover this migration path and validate that.
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