Kompose will read input from stdin

Resolves issue #870

for example,

```
$ cat docker-compose.yaml | kompose convert -f -
INFO Kubernetes file "frontend-service.yaml" created
INFO Kubernetes file "redis-master-service.yaml" created
INFO Kubernetes file "redis-slave-service.yaml" created
INFO Kubernetes file "frontend-deployment.yaml" created
INFO Kubernetes file "redis-master-deployment.yaml" created
INFO Kubernetes file "redis-slave-deployment.yaml" created
```

Added integration test for the same.
`

.travis.yml

@@ -24,6 +24,7 @@ install:
   - script/test/cmd/fix_detached_head.sh
 
 script:
+  - make bin
   - make test
   # Only cross-compile once
   - if [ "$CROSS_COMPILE" == "yes" ]; then make cross; fi

Makefile

@@ -65,6 +65,8 @@ test-openshift:
 .PHONY: test-cmd
 test-cmd:
 	./script/test/cmd/tests.sh
+	go test -v github.com/kubernetes/kompose/script/test/cmd
+
 
 # run all validation tests
 .PHONY: validate

pkg/loader/compose/compose.go

@@ -24,6 +24,9 @@ import (
 
 	yaml "gopkg.in/yaml.v2"
 
+	"bufio"
+	"os"
+
 	"github.com/docker/libcompose/project"
 	"github.com/fatih/structs"
 	"github.com/kubernetes/kompose/pkg/kobject"
@@ -199,10 +202,16 @@ func getVersionFromFile(file string) (string, error) {
 		Version string `json:"version"` // This affects YAML as well
 	}
 	var version ComposeVersion
-
-	loadedFile, err := ioutil.ReadFile(file)
-	if err != nil {
-		return "", err
+	var loadedFile []byte
+	var err error
+	if file == "-" {
+		data := bufio.NewScanner(os.Stdin)
+		loadedFile = data.Bytes()
+	} else {
+		loadedFile, err = ioutil.ReadFile(file)
+		if err != nil {
+			return "", err
+		}
 	}
 
 	err = yaml.Unmarshal(loadedFile, &version)

script/test/cmd/cmd_test.go

@@ -0,0 +1,30 @@
+package cmd
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"testing"
+)
+
+var Fixtures = os.ExpandEnv("$GOPATH/src/github.com/kubernetes/kompose/script/test/fixtures/")
+var ProjectPath = "$GOPATH/src/github.com/kubernetes/kompose/"
+var BinaryLocation = os.ExpandEnv(ProjectPath + "kompose")
+
+func Test_stdin(t *testing.T) {
+
+	kjson := `{"version": "2","services": {"redis": {"image": "redis:3.0","ports": ["6379"]}}}`
+	cmdStr := fmt.Sprintf("%s convert --stdout -f - <<EOF\n%s\nEOF\n", BinaryLocation, kjson)
+	subproc := exec.Command("/bin/sh", "-c", cmdStr)
+	output, err := subproc.Output()
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	g, err := ioutil.ReadFile(Fixtures + "stdin/output.yml")
+	if !bytes.Equal(output, g) {
+		t.Errorf("Test Failed")
+	}
+}
+

script/test/fixtures/stdin/output.yml

@@ -0,0 +1,53 @@
+apiVersion: v1
+items:
+- apiVersion: v1
+  kind: Service
+  metadata:
+    annotations:
+      kompose.cmd: /home/snarwade/go/src/github.com/kubernetes/kompose/kompose convert
+        --stdout -f -
+      kompose.version: 1.6.0 (HEAD)
+    creationTimestamp: null
+    labels:
+      io.kompose.service: redis
+    name: redis
+  spec:
+    ports:
+    - name: "6379"
+      port: 6379
+      targetPort: 6379
+    selector:
+      io.kompose.service: redis
+  status:
+    loadBalancer: {}
+- apiVersion: extensions/v1beta1
+  kind: Deployment
+  metadata:
+    annotations:
+      kompose.cmd: /home/snarwade/go/src/github.com/kubernetes/kompose/kompose convert
+        --stdout -f -
+      kompose.version: 1.6.0 (HEAD)
+    creationTimestamp: null
+    labels:
+      io.kompose.service: redis
+    name: redis
+  spec:
+    replicas: 1
+    strategy: {}
+    template:
+      metadata:
+        creationTimestamp: null
+        labels:
+          io.kompose.service: redis
+      spec:
+        containers:
+        - image: redis:3.0
+          name: redis
+          ports:
+          - containerPort: 6379
+          resources: {}
+        restartPolicy: Always
+  status: {}
+kind: List
+metadata: {}
+

script/test_k8s/kubernetes.sh

@@ -117,6 +117,13 @@ test_k8s() {
     ./kompose down -f $f --controller=replicationcontroller
 
   done
+
+  echo -e "\nTesting stdin to kompose\n"
+  echo -e "\n${RED}cat examples/docker-compose.yaml | ./kompose up -f -${NC}\n"
+  cat examples/docker-compose.yaml | ./kompose up -f -
+  sleep 2 # Sleep for k8s to catch up to deployment
+  echo -e "\n${RED}cat examples/docker-compose.yaml | ./kompose down -f - ${NC}\n"
+  cat examples/docker-compose.yaml | ./kompose down -f -
 }
 
 if [[ $1 == "start" ]]; then