[metrics-bugs] #24290 [Metrics/CollecTor]: Use timeout for fetching remote index.json in DescriptorIndexCollector

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#24290: Use timeout for fetching remote index.json in DescriptorIndexCollector
-----------------------------------+--------------------------
     Reporter:  karsten            |      Owner:  metrics-team
         Type:  defect             |     Status:  new
     Priority:  High               |  Milestone:
    Component:  Metrics/CollecTor  |    Version:
     Severity:  Normal             |   Keywords:
Actual Points:                     |  Parent ID:
       Points:                     |   Reviewer:
      Sponsor:                     |
-----------------------------------+--------------------------
 Tonight the relaydescs module of the main CollecTor instance froze when
 attempting to fetch the remote index.json from the backup CollecTor
 instance. Here's a stack trace I got from `jcmd`:

 {{{
 "CollecTor-Scheduled-Thread-10" #38 daemon prio=5 os_prio=0
 tid=0x00007fb7ac009800 nid=0xea7 runnable [0x00007fb7e5893000]
    java.lang.Thread.State: RUNNABLE
         at java.net.SocketInputStream.socketRead0(Native Method)
         at
 java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
         at java.net.SocketInputStream.read(SocketInputStream.java:171)
         at java.net.SocketInputStream.read(SocketInputStream.java:141)
         at sun.security.ssl.InputRecord.readFully(InputRecord.java:465)
         at sun.security.ssl.InputRecord.read(InputRecord.java:503)
         at
 sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:983)
         - locked <0x000000008061f060> (a java.lang.Object)
         at
 sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1385)
         - locked <0x000000008061f188> (a java.lang.Object)
         at
 sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1413)
         at
 sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1397)
         at
 sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:559)
         at
 sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185)
         at
 sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1564)
         - locked <0x000000008061f1f8> (a
 sun.net.www.protocol.https.DelegateHttpsURLConnection)
         at
 sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1492)
         - locked <0x000000008061f1f8> (a
 sun.net.www.protocol.https.DelegateHttpsURLConnection)
         at
 sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:263)
         - locked <0x000000008061f2e0> (a
 sun.net.www.protocol.https.HttpsURLConnectionImpl)
         at java.net.URL.openStream(URL.java:1045)
         at
 org.torproject.descriptor.index.IndexNode.fetchIndex(IndexNode.java:101)
         at
 org.torproject.descriptor.index.DescriptorIndexCollector.collectDescriptors(DescriptorIndexCollector.java:74)
         at
 org.torproject.collector.sync.SyncManager.collectFromOtherInstances(SyncManager.java:59)
         at
 org.torproject.collector.sync.SyncManager.merge(SyncManager.java:43)
         at
 org.torproject.collector.cron.CollecTorMain.run(CollecTorMain.java:76)
         at
 java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
         at
 java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
         at
 java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
         at
 java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
         at
 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
         at
 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
         at java.lang.Thread.run(Thread.java:748)
 }}}

 I didn't look at the code in detail, but I could imagine that a timeout
 would have helped in this case. Maybe there are other possible fixes,
 though.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/24290>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
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