Speed up kustainer creates and tear downs

Kustainer spawns Kusto through bash, so the normal shutdown signals do
not get passed through. This means that the processes take 10s to
shutdown after timeouts. Instead, create the container with an init
process that can adopt the Kusto process with bash exits and can reap
the process.

Author: Mike Keesey

pkg/testutils/kustainer/kustainer.go

@@ -19,6 +19,7 @@ import (
 	"github.com/Azure/adx-mon/pkg/testutils"
 	"github.com/Azure/azure-kusto-go/kusto"
 	"github.com/Azure/azure-kusto-go/kusto/kql"
+	"github.com/docker/docker/api/types/container"
 	"github.com/testcontainers/testcontainers-go"
 	"github.com/testcontainers/testcontainers-go/modules/k3s"
 	"github.com/testcontainers/testcontainers-go/wait"
@@ -39,15 +40,19 @@ type KustainerContainer struct {
 }
 
 func Run(ctx context.Context, img string, opts ...testcontainers.ContainerCustomizer) (*KustainerContainer, error) {
+	initEnabled := true
 	req := testcontainers.ContainerRequest{
 		Image:        img,
 		ExposedPorts: []string{"8080/tcp"},
 		Env: map[string]string{
 			"ACCEPT_EULA": "Y",
 		},
+		HostConfigModifier: func(hc *container.HostConfig) {
+			hc.Init = &initEnabled // Enable tini init process to handle reaping, which greatly speeds up shutting down this container
+		},
 		WaitingFor: wait.ForAll(
-			wait.ForListeningPort("8080/tcp"),
-			wait.ForLog(".*Hit 'CTRL-C' or 'CTRL-BREAK' to quit.*").AsRegexp(),
+			wait.ForListeningPort("8080/tcp").WithPollInterval(50*time.Millisecond),
+			wait.ForLog(".*Hit 'CTRL-C' or 'CTRL-BREAK' to quit.*").AsRegexp().WithPollInterval(50*time.Millisecond),
 		),
 	}
 	genericContainerReq := testcontainers.GenericContainerRequest{