Added exponential backoff during image pull

Signed-off-by: Gianluca Arbezzano <[email protected]>

docker.go

@@ -10,6 +10,7 @@ import (
 	"os/exec"
 	"strings"
 
+	"github.com/cenkalti/backoff"
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/container"
 	"github.com/docker/docker/api/types/mount"
@@ -258,7 +259,12 @@ func (p *DockerProvider) CreateContainer(ctx context.Context, req ContainerReque
 			if req.RegistryCred != "" {
 				pullOpt.RegistryAuth = req.RegistryCred
 			}
-			pull, err := p.client.ImagePull(ctx, req.Image, pullOpt)
+			var pull io.ReadCloser
+			err := backoff.Retry(func() error {
+				var err error
+				pull, err = p.client.ImagePull(ctx, req.Image, pullOpt)
+				return err
+			}, backoff.NewExponentialBackOff())
 			if err != nil {
 				return nil, err
 			}

go.mod

@@ -5,6 +5,7 @@ replace github.com/docker/docker => github.com/docker/engine v0.0.0-201907171610
 require (
 	github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78 // indirect
 	github.com/Microsoft/go-winio v0.4.11 // indirect
+	github.com/cenkalti/backoff v2.2.1+incompatible
 	github.com/docker/distribution v2.7.1-0.20190205005809-0d3efadf0154+incompatible // indirect
 	github.com/docker/docker v0.7.3-0.20190506211059-b20a14b54661
 	github.com/docker/go-connections v0.4.0

go.sum

@@ -3,6 +3,8 @@ github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78 h1:w+iIsaOQNcT7O
 github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78/go.mod h1:LmzpDX56iTiv29bbRTIsUNlaFfuhWRQBWjQdVyAevI8=
 github.com/Microsoft/go-winio v0.4.11 h1:zoIOcVf0xPN1tnMVbTtEdI+P8OofVk3NObnwOQ6nK2Q=
 github.com/Microsoft/go-winio v0.4.11/go.mod h1:VhR8bwka0BXejwEJY73c50VrPtXAaKcyvVC4A4RozmA=
+github.com/cenkalti/backoff v2.2.1+incompatible h1:tNowT99t7UNflLxfYYSlKYsBpXdEet03Pg2g16Swow4=
+github.com/cenkalti/backoff v2.2.1+incompatible/go.mod h1:90ReRw6GdpyfrHakVjL/QHaoyV4aDUVVkXQJJJ3NXXM=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=