From 09dc77aedfb786505bc526536be18d457fb7c68b Mon Sep 17 00:00:00 2001 From: Valentin Rothberg Date: Thu, 9 Jul 2020 13:32:20 +0200 Subject: log API: add context to allow for cancelling Add a `context.Context` to the log APIs to allow for cancelling streaming (e.g., via `podman logs -f`). This fixes issues for the remote API where some go routines of the server will continue writing and produce nothing but heat and waste CPU cycles. Signed-off-by: Valentin Rothberg --- libpod/container_log.go | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) (limited to 'libpod/container_log.go') diff --git a/libpod/container_log.go b/libpod/container_log.go index 97936c683..80f8e6e50 100644 --- a/libpod/container_log.go +++ b/libpod/container_log.go @@ -1,6 +1,7 @@ package libpod import ( + "context" "fmt" "os" "time" @@ -13,9 +14,9 @@ import ( ) // Log is a runtime function that can read one or more container logs. -func (r *Runtime) Log(containers []*Container, options *logs.LogOptions, logChannel chan *logs.LogLine) error { +func (r *Runtime) Log(ctx context.Context, containers []*Container, options *logs.LogOptions, logChannel chan *logs.LogLine) error { for _, ctr := range containers { - if err := ctr.ReadLog(options, logChannel); err != nil { + if err := ctr.ReadLog(ctx, options, logChannel); err != nil { return err } } @@ -23,25 +24,25 @@ func (r *Runtime) Log(containers []*Container, options *logs.LogOptions, logChan } // ReadLog reads a containers log based on the input options and returns loglines over a channel. -func (c *Container) ReadLog(options *logs.LogOptions, logChannel chan *logs.LogLine) error { +func (c *Container) ReadLog(ctx context.Context, options *logs.LogOptions, logChannel chan *logs.LogLine) error { switch c.LogDriver() { case define.NoLogging: return errors.Wrapf(define.ErrNoLogs, "this container is using the 'none' log driver, cannot read logs") case define.JournaldLogging: // TODO Skip sending logs until journald logs can be read - return c.readFromJournal(options, logChannel) + return c.readFromJournal(ctx, options, logChannel) case define.JSONLogging: // TODO provide a separate implementation of this when Conmon // has support. fallthrough case define.KubernetesLogging, "": - return c.readFromLogFile(options, logChannel) + return c.readFromLogFile(ctx, options, logChannel) default: return errors.Wrapf(define.ErrInternal, "unrecognized log driver %q, cannot read logs", c.LogDriver()) } } -func (c *Container) readFromLogFile(options *logs.LogOptions, logChannel chan *logs.LogLine) error { +func (c *Container) readFromLogFile(ctx context.Context, options *logs.LogOptions, logChannel chan *logs.LogLine) error { t, tailLog, err := logs.GetLogFile(c.LogPath(), options) if err != nil { // If the log file does not exist, this is not fatal. @@ -62,8 +63,17 @@ func (c *Container) readFromLogFile(options *logs.LogOptions, logChannel chan *l } go func() { + defer options.WaitGroup.Done() + var partial string for line := range t.Lines { + select { + case <-ctx.Done(): + // the consumer has cancelled + return + default: + // fallthrough + } nll, err := logs.NewLogLine(line.Text) if err != nil { logrus.Error(err) @@ -82,7 +92,6 @@ func (c *Container) readFromLogFile(options *logs.LogOptions, logChannel chan *l logChannel <- nll } } - options.WaitGroup.Done() }() // Check if container is still running or paused if options.Follow { -- cgit v1.2.3-54-g00ecf