Implement image pull according to ImatePullPolicy

fix #1

Signed-off-by: Nicolas De Loof <[email protected]>

Author: ndeloof

go.mod

@@ -3,6 +3,7 @@ module github.com/ndeloof/kitten
 go 1.12
 
 require (
+	github.com/Nvveen/Gotty v0.0.0-20120604004816-cd527374f1e5 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/docker/distribution v2.7.1+incompatible // indirect
 	github.com/docker/docker v0.0.0-20180422163414-57142e89befe

go.sum

@@ -1,4 +1,6 @@
 cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+github.com/Nvveen/Gotty v0.0.0-20120604004816-cd527374f1e5 h1:TngWCqHvy9oXAN6lEVMRuU21PR1EtLVZJmdB18Gu3Rw=
+github.com/Nvveen/Gotty v0.0.0-20120604004816-cd527374f1e5/go.mod h1:lmUJ/7eu/Q8D7ML55dXQrVaamCz2vxCfdQBasLZfHKk=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 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=
@@ -35,6 +37,8 @@ github.com/google/gofuzz v1.0.0 h1:A8PeW59pxE9IoFRqBp37U+mSNaQoZ46F1f0f863XSXw=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/uuid v1.0.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/googleapis/gnostic v0.0.0-20170729233727-0c5108395e2d/go.mod h1:sJBsCZ4ayReDTBIg8b9dl28c5xFWyhBTVRp3pOg5EKY=
+github.com/gotestyourself/gotestyourself v2.2.0+incompatible h1:AQwinXlbQR2HvPjQZOmDhRqsv5mZf+Jb1RnSLxcqZcI=
+github.com/gotestyourself/gotestyourself v2.2.0+incompatible/go.mod h1:zZKM6oeNM8k+FRljX1mnzVYeS8wiGgQyvST1/GafPbY=
 github.com/goware/prefixer v0.0.0-20160118172347-395022866408 h1:Y9iQJfEqnN3/Nce9cOegemcy/9Ai5k3huT6E80F3zaw=
 github.com/goware/prefixer v0.0.0-20160118172347-395022866408/go.mod h1:PE1ycukgRPJ7bJ9a1fdfQ9j8i/cEcRAoLZzbxYpNB/s=
 github.com/hashicorp/golang-lru v0.5.0 h1:CL2msUPvZTLb5O648aiLNJw3hnBxN2+1Jq8rCOH9wdo=
@@ -116,6 +120,8 @@ gopkg.in/yaml.v2 v2.2.1 h1:mUhvW9EsL+naU5Q3cakzfE91YhliOondGd6ZrsDBHQE=
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gotest.tools v2.2.0+incompatible h1:VsBPFP1AI068pPrMxtb/S8Zkgf9xEmTLJjfM+P5UIEo=
+gotest.tools v2.2.0+incompatible/go.mod h1:DsYFclhRJ6vuDpmuTbkuFWG+y2sxOXAzmJt81HFBacw=
 k8s.io/api v0.0.0-20190222213804-5cb15d344471 h1:MzQGt8qWQCR+39kbYRd0uQqsvSidpYqJLFeWiJ9l4OE=
 k8s.io/api v0.0.0-20190222213804-5cb15d344471/go.mod h1:iuAfoD4hCxJ8Onx9kaTIt30j7jUFS00AXQi6QMi99vA=
 k8s.io/api v0.0.0-20190515023547-db5a9d1c40eb h1:z1fFVKHVQNtGcAPbYljoW2rZT+0ITuj99cmGH9RBrWE=

pkg/crds/testdata/pipeline.yaml

@@ -1,4 +1,12 @@
 apiVersion: tekton.dev/v1alpha1
+kind: PipelineRun
+metadata:
+  name: demo
+spec:
+  pipelineRef:
+    name: sample-pipeline
+---
+apiVersion: tekton.dev/v1alpha1
 kind: Pipeline
 metadata:
   name: sample-pipeline
@@ -15,5 +23,5 @@ metadata:
 spec:
   steps:
   - name: foo
-    image: alpine
+    image: ubuntu
     command: ['echo', 'hello foo']

pkg/kitten/kitten.go

@@ -8,9 +8,12 @@ import (
 	"github.com/goware/prefixer"
 	pipeline "github.com/tektoncd/pipeline/pkg/apis/pipeline/v1alpha1"
 	"github.com/tektoncd/pipeline/pkg/reconciler/v1alpha1/pipeline/dag"
+	k8s "k8s.io/api/core/v1"
 
+	"encoding/json"
 	"fmt"
 	"github.com/docker/docker/client"
+	message "github.com/docker/docker/pkg/jsonmessage"
 	"github.com/ndeloof/kitten/pkg/crds"
 	"io"
 	"os"
@@ -91,7 +94,42 @@ func RunTask(ctx context.Context, pt pipeline.PipelineTask, task pipeline.Task,
 		cmd = append(cmd, s.Command...)
 		cmd = append(cmd, s.Args...)
 
-		cli.ImagePull(ctx, s.Image, types.ImagePullOptions{})
+		pull := s.ImagePullPolicy == k8s.PullAlways
+		if s.ImagePullPolicy != k8s.PullNever {
+			_, _, err := cli.ImageInspectWithRaw(ctx, s.Image)
+			if err != nil {
+				if client.IsErrNotFound(err) {
+					pull = true
+				} else {
+					return 0, fmt.Errorf("can't inspect image. %v", err)
+				}
+			}
+		}
+
+		if pull {
+			fmt.Printf("Pulling Docker image %s\n", s.Image)
+			resp, err := cli.ImagePull(ctx, s.Image, types.ImagePullOptions{})
+			if err != nil {
+				return 0, fmt.Errorf("can't pull docker image. %v", err)
+			}
+			defer resp.Close()
+			decoder := json.NewDecoder(resp)
+			for {
+				var msg message.JSONMessage
+				err := decoder.Decode(&msg)
+				if err == io.EOF {
+					// Completed
+					break
+				}
+				if err != nil {
+					return 0, fmt.Errorf("failed to pull docker image. %v", err)
+				}
+				if msg.Error != nil {
+					return 0, fmt.Errorf("failed to pull docker image. %v", msg.Error)
+				}
+				fmt.Println(msg.ProgressMessage)
+			}
+		}
 
 		c, err := cli.ContainerCreate(ctx,
 			&container.Config{