[improve][broker] Change log level to reduce duplicated logs

[mattisonchao]

Motivation

Some vendors' environments do not support reading virtual NIC type. The broker will constantly print the useless warning log, which will increase the storage cost.

The demo logs is as follows:

[pulsar-load-manager-1-1] WARN  org.apache.pulsar.broker.loadbalance.LinuxInfoUtils - [LinuxInfo] Failed to read /sys/class/net/nc1 NIC type, the detail is: /sys/class/net/nc1/type: Not a directory
[pulsar-load-manager-1-1] WARN  org.apache.pulsar.broker.loadbalance.LinuxInfoUtils - [LinuxInfo] Failed to read /sys/class/net/nc1 NIC type, the detail is: /sys/class/net/nc1/type: Not a directory
[pulsar-load-manager-1-1] WARN  org.apache.pulsar.broker.loadbalance.LinuxInfoUtils - [LinuxInfo] Failed to read /sys/class/net/nc1 NIC type, the detail is: /sys/class/net/nc1/type: Not a directory

Modifications

• Because this is the judgement of boolean. It's okay to move the log to be debug level.

Verifying this change

• Make sure that the change passes the CI checks.

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

[asafm]

@mattisonchao Can you explain why this log is printed so many times?

[lhotari]

In this case, the file doesn't even seem to exist. Could we avoid the exception in the first place by checking with java.nio.file.Files#isReadable if the file exists and is readable? Does Files.isReadable check work for these special /sys/class/net files?

[mattisonchao]

@mattisonchao Can you explain why this log is printed so many times?

@asafm Because the broker needs to report the load data constantly and then this judgement method will invoke many times. :)

pulsar/pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/LinuxInfoUtils.java

Line 276 in 3b3c713

return stream.filter(LinuxInfoUtils::isPhysicalNic)

[mattisonchao]

In this case, the file doesn't even seem to exist. Could we avoid the exception in the first place by checking with java.nio.file.Files#isReadable if the file exists and is readable? Does Files.isReadable check work for these special /sys/class/net files?

This method is only used to judge whether the current NIC is physical. IMO, the exception status also means not a valid physical NIC. I think giving it a debug-level log for troubleshooting is enough.

And yes, we can give an extra operation to check if the current file type exists. but for the other exceptions, we still need to not print logs in the warn or error level to avoid annoying logs.

cc @lhotari

[lhotari]

In this case, the file doesn't even seem to exist. Could we avoid the exception in the first place by checking with java.nio.file.Files#isReadable if the file exists and is readable? Does Files.isReadable check work for these special /sys/class/net files?

This method is only used to judge whether the current NIC is physical. IMO, the exception status also means not a valid physical NIC. I think giving it a debug-level log for troubleshooting is enough.

And yes, we can give an extra operation to check if the current file type exists. but for the other exceptions, we still need to not print logs in the warn or error level to avoid annoying logs.

cc @lhotari

I think it's better to avoid exceptions and add a file existence check since we are touching this part of the code.

[mattisonchao]

Applied the comment. cc @lhotari

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 22.22222% with 7 lines in your changes are missing coverage. Please review.

Project coverage is 38.30%. Comparing base (bbc6224) to head (40b5957).
Report is 27 commits behind head on master.

Additional details and impacted files

@@              Coverage Diff              @@
##             master   #22147       +/-   ##
=============================================
- Coverage     73.57%   38.30%   -35.27%     
+ Complexity    32624    12168    -20456     
=============================================
  Files          1877     1737      -140     
  Lines        139502   132494     -7008     
  Branches      15299    14520      -779     
=============================================
- Hits         102638    50757    -51881     
- Misses        28908    74973    +46065     
+ Partials       7956     6764     -1192     

Flag	Coverage Δ
inttests	26.76% <22.22%> (+2.18%)	⬆️
systests	24.26% <22.22%> (-0.07%)	⬇️
unittests	31.83% <22.22%> (-41.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
...ache/pulsar/broker/loadbalance/LinuxInfoUtils.java	36.64% <22.22%> (-19.71%)	⬇️

... and 1441 files with indirect coverage changes