yanyan300300 commented on a change in pull request #8215: [FLINK-8801][yarn/s3]
Fix jars downloading issues due to inconsistent timestamp in S3 Filesystem
URL: https://github.com/apache/flink/pull/8215#discussion_r299571156
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File path: flink-yarn/src/main/java/org/apache/flink/yarn/Utils.java
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@@ -161,15 +169,37 @@ public static void setupYarnClassPath(Configuration
conf, Map<String, String> ap
fs.copyFromLocalFile(false, true, localSrcPath, dst);
- // Note: If we used registerLocalResource(FileSystem, Path)
here, we would access the remote
+ // Note: If we directly used registerLocalResource(FileSystem,
Path) here, we would access the remote
// file once again which has problems with eventually
consistent read-after-write file
- // systems. Instead, we decide to preserve the
modification time at the remote
- // location because this and the size of the resource
will be checked by YARN based on
- // the values we provide to #registerLocalResource()
below.
- fs.setTimes(dst, localFile.lastModified(), -1);
- // now create the resource instance
- LocalResource resource = registerLocalResource(dst,
localFile.length(), localFile.lastModified());
+ // systems. Instead, we decide to wait until the remote
file be available.
+ FileStatus[] fss = null;
+ int iter = 1;
+ while (iter <= REMOTE_RESOURCES_FETCH_NUM_RETRY + 1) {
+ try {
+ fss = fs.listStatus(dst);
+ break;
+ } catch (FileNotFoundException e) {
+ LOG.debug("Got FileNotFoundException while
fetching uploaded remote resources at retry num {}", iter);
+ try {
+ LOG.debug("Sleeping for {}ms",
REMOTE_RESOURCES_FETCH_WAIT_IN_MILLI);
+
TimeUnit.MILLISECONDS.sleep(REMOTE_RESOURCES_FETCH_WAIT_IN_MILLI);
+ } catch (InterruptedException ie) {
+ LOG.warn("Failed to sleep for {}ms at
retry num {} while fetching uploaded remote resources",
+
REMOTE_RESOURCES_FETCH_WAIT_IN_MILLI, iter, ie);
+ }
+ iter++;
+ }
+ }
+ long dstModificationTime = -1;
+ if (fss != null && fss.length > 0) {
+ dstModificationTime = fss[0].getModificationTime();
+ }
+ LOG.debug("Got modification time {} from remote path {}",
dstModificationTime, dst);
+
+ // now create the resource instance
+ LocalResource resource = registerLocalResource(dst,
localFile.length(), dstModificationTime > 0 ? dstModificationTime
+ : localFile.lastModified());
Review comment:
Thanks for the suggestion. When a var can be assigned to different values,
personally I prefer to use a default and then override it for other scenarios.
There are two benefits: 1) reduce the required number of if/else branches 2)
higher line coverage. In this relatively simple case, yes what you suggest also
fits.
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