stats: add a interval parameter to cli and api stream mode

podman stats polled by default in a 1 sec period.
This can put quite some load on a machine if you run many containers.

The default value is now 5 seconds.
You can change this interval with a new, optional, --interval, -i cli flag.
The api request got also a interval query parameter for the same purpose.

Additionally a unused const was removed.
Api and cli will fail the request if a 0 or negative value is passed in.

Signed-off-by: Thomas Weber <towe75@googlemail.com>

3 files changed, 7 insertions, 2 deletions

diff --git a/pkg/domain/entities/containers.go b/pkg/domain/entities/containers.go
index 302b35a47..dcb351e82 100644
--- a/pkg/domain/entities/containers.go
+++ b/pkg/domain/entities/containers.go
@@ -435,6 +435,8 @@ type ContainerStatsOptions struct {
 	Latest bool
 	// Stream stats.
 	Stream bool
+	// Interval in seconds
+	Interval int
 }
 
 // ContainerStatsReport is used for streaming container stats.
diff --git a/pkg/domain/infra/abi/containers.go b/pkg/domain/infra/abi/containers.go
index 50751aa12..6eeef870f 100644
--- a/pkg/domain/infra/abi/containers.go
+++ b/pkg/domain/infra/abi/containers.go
@@ -1281,6 +1281,9 @@ func (ic *ContainerEngine) Shutdown(_ context.Context) {
 }
 
 func (ic *ContainerEngine) ContainerStats(ctx context.Context, namesOrIds []string, options entities.ContainerStatsOptions) (statsChan chan entities.ContainerStatsReport, err error) {
+	if options.Interval < 1 {
+		return nil, errors.New("Invalid interval, must be a positive number greater zero")
+	}
 	statsChan = make(chan entities.ContainerStatsReport, 1)
 
 	containerFunc := ic.Libpod.GetRunningContainers
@@ -1361,7 +1364,7 @@ func (ic *ContainerEngine) ContainerStats(ctx context.Context, namesOrIds []stri
 			return
 		}
 
-		time.Sleep(time.Second)
+		time.Sleep(time.Second * time.Duration(options.Interval))
 		goto stream
 	}()
 
diff --git a/pkg/domain/infra/tunnel/containers.go b/pkg/domain/infra/tunnel/containers.go
index c17d7b54f..1df79c373 100644
--- a/pkg/domain/infra/tunnel/containers.go
+++ b/pkg/domain/infra/tunnel/containers.go
@@ -871,7 +871,7 @@ func (ic *ContainerEngine) ContainerStats(ctx context.Context, namesOrIds []stri
 	if options.Latest {
 		return nil, errors.New("latest is not supported for the remote client")
 	}
-	return containers.Stats(ic.ClientCtx, namesOrIds, new(containers.StatsOptions).WithStream(options.Stream))
+	return containers.Stats(ic.ClientCtx, namesOrIds, new(containers.StatsOptions).WithStream(options.Stream).WithInterval(options.Interval))
 }
 
 // ShouldRestart reports back whether the container will restart