journald logs: keep reading until the journal's end

When reading logs from the journal, keep going after the container
exits, in case it gets restarted.

Events logged to the journal via the normal paths don't include
CONTAINER_ID_FULL, so don't bother adding it to the "history" event we
use to force at least one entry for the container to show up in the log.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

2 files changed, 31 insertions, 4 deletions

diff --git a/libpod/container_log_linux.go b/libpod/container_log_linux.go
index 4029d0af7..c5e145b7d 100644
--- a/libpod/container_log_linux.go
+++ b/libpod/container_log_linux.go
@@ -37,9 +37,11 @@ func (c *Container) initializeJournal(ctx context.Context) error {
 	m := make(map[string]string)
 	m["SYSLOG_IDENTIFIER"] = "podman"
 	m["PODMAN_ID"] = c.ID()
-	m["CONTAINER_ID_FULL"] = c.ID()
 	history := events.History
 	m["PODMAN_EVENT"] = history.String()
+	container := events.Container
+	m["PODMAN_TYPE"] = container.String()
+	m["PODMAN_TIME"] = time.Now().Format(time.RFC3339Nano)
 	return journal.Send("", journal.PriInfo, m)
 }
 
@@ -89,6 +91,7 @@ func (c *Container) readFromJournal(ctx context.Context, options *logs.LogOption
 	// exponential backoff.
 	var cursor string
 	var cursorError error
+	var containerCouldBeLogging bool
 	for i := 1; i <= 3; i++ {
 		cursor, cursorError = journal.GetCursor()
 		hundreds := 1
@@ -172,7 +175,7 @@ func (c *Container) readFromJournal(ctx context.Context, options *logs.LogOption
 					doTailFunc()
 				}
 				// Unless we follow, quit.
-				if !options.Follow {
+				if !options.Follow || !containerCouldBeLogging {
 					return
 				}
 				// Sleep until something's happening on the journal.
@@ -201,11 +204,14 @@ func (c *Container) readFromJournal(ctx context.Context, options *logs.LogOption
 					logrus.Errorf("Failed to translate event: %v", err)
 					return
 				}
-				if status == events.Exited {
+				switch status {
+				case events.History, events.Init, events.Start, events.Restart:
+					containerCouldBeLogging = true
+				case events.Exited:
+					containerCouldBeLogging = false
 					if doTail {
 						doTailFunc()
 					}
-					return
 				}
 				continue
 			}
diff --git a/test/system/035-logs.bats b/test/system/035-logs.bats
index 7fb3e62e4..44984eaad 100644
--- a/test/system/035-logs.bats
+++ b/test/system/035-logs.bats
@@ -89,6 +89,27 @@ ${cid[0]} d"   "Sequential output from logs"
     _log_test_multi journald
 }
 
+function _log_test_restarted() {
+    run_podman run --log-driver=$1 --name logtest $IMAGE sh -c 'start=0; if test -s log; then start=`tail -n 1 log`; fi; seq `expr $start + 1` `expr $start + 10` | tee -a log'
+    run_podman start -a logtest
+    logfile=$(mktemp -p ${PODMAN_TMPDIR} logfileXXXXXXXX)
+    $PODMAN $_PODMAN_TEST_OPTS logs -f logtest > $logfile
+    expected=$(mktemp -p ${PODMAN_TMPDIR} expectedXXXXXXXX)
+    seq 1 20  > $expected
+    diff -u ${expected} ${logfile}
+}
+
+@test "podman logs restarted - k8s-file" {
+    _log_test_restarted k8s-file
+}
+
+@test "podman logs restarted journald" {
+    # We can't use journald on RHEL as rootless: rhbz#1895105
+    skip_if_journald_unavailable
+
+    _log_test_restarted journald
+}
+
 @test "podman logs - journald log driver requires journald events backend" {
     skip_if_remote "remote does not support --events-backend"
     # We can't use journald on RHEL as rootless: rhbz#1895105