fix(resource-monitoring): fix lsof file descriptor leak

[yumosx]

Description

Add caching mechanism for file descriptor count to avoid frequent lsof command execution. Implement periodic updates with configurable interval to maintain accuracy while preventing resource leaks. Add tests to verify caching behavior and update intervals.

Fixes: continue cli leaking lsof execs · Issue #9422 · continuedev/continue

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• I've read the contributing guide
• The relevant docs, if any, have been updated or created
• The relevant tests, if any, have been updated or created

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Tests

1. Check which process is running the target script
   Run the following command to find the process:

   ps aux | grep "node cn.js --verbose"
   

2. Observe the output and note the PID

   root     13448  0.9  1.8 22474448 299940 pts/2 Sl+  02:09   0:13 node cn.js --verbose
   

   → The process ID (PID) is 13448.

3. Create a simple monitoring script to watch lsof behavior on that PID
   Create a bash script (for example monitor.sh) with the following content:

   #!/bin/bash
   echo "Starting monitoring..."
   while true; do
       if pgrep -f "lsof -p 13448" >/dev/null 2>&1; then
           date '+%H:%M:%S.%N - lsof executing'
       fi
   done

4. Run the monitoring script
   Execute it in the background or in another terminal:

   bash monitor.sh
   

   (or ./monitor.sh after chmod +x monitor.sh)

5. Observe the result
   You will see frequent/tight timestamps whenever the command lsof -p 13448 is actively running:

   02:39:10.970678309 - lsof executing
   02:39:10.972740008 - lsof executing
   02:39:10.974828662 - lsof executing
   02:39:10.977207083 - lsof executing
   02:39:15.941282960 - lsof executing
   ...
   

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[cubic-dev-ai]

3 issues found across 2 files

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="extensions/cli/src/services/ResourceMonitoringService.test.ts">

<violation number="1" location="extensions/cli/src/services/ResourceMonitoringService.test.ts:124">
P2: Leak regression test is ineffective: it performs no assertion when lsof is unavailable and doesn’t verify lsof call frequency, so a leak can slip through undetected.</violation>

<violation number="2" location="extensions/cli/src/services/ResourceMonitoringService.test.ts:137">
P2: FD refresh interval test never exercises refresh and has no effective assertion; it always passes even if refresh doesn’t occur.</violation>
</file>

<file name="extensions/cli/src/services/ResourceMonitoringService.ts">

<violation number="1" location="extensions/cli/src/services/ResourceMonitoringService.ts:134">
P1: updateFileDescriptorCount() runs on every getCurrentResourceUsage call, spawning lsof every second despite intended 5s throttling</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[yumosx]

tests for this pr:

1. Check which process is running the target script
   Run the following command to find the process:

   ps aux | grep "node cn.js --verbose"
   

2. Observe the output and note the PID

   root     13448  0.9  1.8 22474448 299940 pts/2 Sl+  02:09   0:13 node cn.js --verbose
   

   → The process ID (PID) is 13448.

3. Create a simple monitoring script to watch lsof behavior on that PID
   Create a bash script (for example monitor.sh) with the following content:

   #!/bin/bash
   echo "Starting monitoring..."
   while true; do
       if pgrep -f "lsof -p 13448" >/dev/null 2>&1; then
           date '+%H:%M:%S.%N - lsof executing'
       fi
   done

4. Run the monitoring script
   Execute it in the background or in another terminal:

   bash monitor.sh
   

   (or ./monitor.sh after chmod +x monitor.sh)

5. Observe the result
   You will see frequent/tight timestamps whenever the command lsof -p 13448 is actively running:

   02:39:10.970678309 - lsof executing
   02:39:10.972740008 - lsof executing
   02:39:10.974828662 - lsof executing
   02:39:10.977207083 - lsof executing
   02:39:15.941282960 - lsof executing
   ...