From b98f05b4f4f6d34a447937d7e49afeec6f827b09 Mon Sep 17 00:00:00 2001
From: Nalin Dahyabhai <nalin@redhat.com>
Date: Fri, 18 Mar 2016 09:06:30 -0400
Subject: [PATCH] Open the journald following descriptor earlier
Following a journal log almost always requires a descriptor to be
allocated. In cases where we're running out of descriptors, this means
we might get stuck while attempting to start following the journal, at a
point where it's too late to report it to the client and clean up
easily. The journal reading context will cache the value once it's
allocated, so here we move the check earlier, so that we can detect a
problem when we can still report it cleanly.
Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>
(cherry picked from commit ab62ecf393b92d1e644f82c4711b6618b7c572a5)
---
daemon/logger/journald/read.go | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/daemon/logger/journald/read.go b/daemon/logger/journald/read.go
index c0bec1f623..1b8b8cce10 100644
--- a/daemon/logger/journald/read.go
+++ b/daemon/logger/journald/read.go
@@ -303,14 +303,21 @@ func (s *journald) readLogs(logWatcher *logger.LogWatcher, config logger.ReadCon
}
cursor = s.drainJournal(logWatcher, config, j, "")
if config.Follow {
- // Create a pipe that we can poll at the same time as the journald descriptor.
- if C.pipe(&pipes[0]) == C.int(-1) {
- logWatcher.Err <- fmt.Errorf("error opening journald close notification pipe")
+ // Allocate a descriptor for following the journal, if we'll
+ // need one. Do it here so that we can report if it fails.
+ if fd := C.sd_journal_get_fd(j); fd < C.int(0) {
+ logWatcher.Err <- fmt.Errorf("error opening journald follow descriptor: %q", C.GoString(C.strerror(-fd)))
} else {
- s.followJournal(logWatcher, config, j, pipes, cursor)
- // Let followJournal handle freeing the journal context
- // object and closing the channel.
- following = true
+ // Create a pipe that we can poll at the same time as
+ // the journald descriptor.
+ if C.pipe(&pipes[0]) == C.int(-1) {
+ logWatcher.Err <- fmt.Errorf("error opening journald close notification pipe")
+ } else {
+ s.followJournal(logWatcher, config, j, pipes, cursor)
+ // Let followJournal handle freeing the journal context
+ // object and closing the channel.
+ following = true
+ }
}
}
return