add imageexits method to check before extracting (#44)

Co-authored-by: Harshvardhan Karn <[email protected]>

Author: ramanan-ravi

containerd/containerd.go

@@ -50,6 +50,15 @@ func (c Containerd) GetSocket() string {
 	return c.socketPath
 }
 
+// ImageExists checks if the image exists
+func (c Containerd) ImageExists(imageName string) bool {
+	_, err := exec.Command("nerdctl", "inspect", imageName, "--address", c.socketPath).Output()
+	if err != nil {
+		return false
+	}
+	return true
+}
+
 // ExtractImage will create the tarball from the containerd image, extracts into dir
 // and then skopeo is used to migrate oci layers using the dir to docker v1 layer spec format tar
 // and again extracts back to dir

crio/crio.go

@@ -20,6 +20,15 @@ func (c CRIO) GetSocket() string {
 	return c.socketPath
 }
 
+// ImageExists checks if the image exists
+func (c CRIO) ImageExists(imageName string) bool {
+	_, err := exec.Command("podman", "inspect", imageName).Output()
+	if err != nil {
+		return false
+	}
+	return true
+}
+
 func (c CRIO) ExtractImage(imageID, imageName, path string) error {
 	cmd := exec.Command("podman", "save", "--events-backend", "file",
 		"--format", "docker-dir", "--output", path, imageName)

docker/docker.go

@@ -23,6 +23,15 @@ func (d Docker) GetSocket() string {
 	return d.socketPath
 }
 
+// ImageExists checks if the image exists
+func (d Docker) ImageExists(imageName string) bool {
+	_, err := exec.Command("docker", "inspect", imageName).Output()
+	if err != nil {
+		return false
+	}
+	return true
+}
+
 // ExtractImage creates the tarball out of image and extracts it
 func (d Docker) ExtractImage(imageID, imageName, path string) error {
 	var stderr bytes.Buffer

integ/imageexists.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"github.com/deepfence/vessel"
+	"github.com/sirupsen/logrus"
+)
+
+func main() {
+	// check if image exists
+	imageName := "nginx:latest"
+	runtime, err := vessel.NewRuntime()
+	if err != nil {
+		logrus.Error(err)
+		return
+	}
+
+	if runtime.ImageExists(imageName) {
+		logrus.Infof("Image %s exists", imageName)
+	} else {
+		logrus.Infof("Image %s does not exist", imageName)
+	}
+}

podman/podman.go

@@ -23,6 +23,15 @@ func (d Podman) GetSocket() string {
 	return d.socketPath
 }
 
+// ImageExists checks if the image exists
+func (d Podman) ImageExists(imageName string) bool {
+	_, err := exec.Command("podman", "--remote", "--url", d.socketPath, "inspect", imageName).Output()
+	if err != nil {
+		return false
+	}
+	return true
+}
+
 // ExtractImage creates the tarball out of image and extracts it
 func (d Podman) ExtractImage(imageID, imageName, path string) error {
 	var stderr bytes.Buffer

runtime.go

@@ -8,4 +8,5 @@ type Runtime interface {
 	GetSocket() string
 	ExtractFileSystem(imageTarPath string, outputTarPath string, imageName string) error
 	ExtractFileSystemContainer(containerId string, namespace string, outputTarPath string) error
+	ImageExists(imageName string) bool
 }