Added tftp datasource for cloud config.

config/cloudinit/datasource/tftp/tftp.go

@@ -0,0 +1,83 @@
+package tftp
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"regexp"
+	"strings"
+
+	"github.com/rancher/os/config/cloudinit/datasource"
+
+	"github.com/pin/tftp"
+)
+
+type Client interface {
+	Receive(filename string, mode string) (io.WriterTo, error)
+}
+
+type RemoteFile struct {
+	host      string
+	path      string
+	client    Client
+	stream    io.WriterTo
+	lastError error
+}
+
+func NewDatasource(hostAndPath string) *RemoteFile {
+	parts := strings.SplitN(hostAndPath, "/", 2)
+
+	if len(parts) < 2 {
+		return &RemoteFile{hostAndPath, "", nil, nil, nil}
+	}
+
+	host := parts[0]
+	if match, _ := regexp.MatchString(":[0-9]{2,5}$", host); !match {
+		// No port, using default port 69
+		host += ":69"
+	}
+
+	path := parts[1]
+	if client, lastError := tftp.NewClient(host); lastError == nil {
+		return &RemoteFile{host, path, client, nil, nil}
+	}
+
+	return &RemoteFile{host, path, nil, nil, nil}
+}
+
+func (f *RemoteFile) IsAvailable() bool {
+	f.stream, f.lastError = f.client.Receive(f.path, "octet")
+	return f.lastError == nil
+}
+
+func (f *RemoteFile) Finish() error {
+	return nil
+}
+
+func (f *RemoteFile) String() string {
+	return fmt.Sprintf("%s: %s%s (lastError: %v)", f.Type(), f.host, f.path, f.lastError)
+}
+
+func (f *RemoteFile) AvailabilityChanges() bool {
+	return false
+}
+
+func (f *RemoteFile) ConfigRoot() string {
+	return ""
+}
+
+func (f *RemoteFile) FetchMetadata() (datasource.Metadata, error) {
+	return datasource.Metadata{}, nil
+}
+
+func (f *RemoteFile) FetchUserdata() ([]byte, error) {
+	var b bytes.Buffer
+
+	_, err := f.stream.WriteTo(&b)
+
+	return b.Bytes(), err
+}
+
+func (f *RemoteFile) Type() string {
+	return "tftp"
+}

config/cloudinit/datasource/tftp/tftp_test.go

@@ -0,0 +1,92 @@
+package tftp
+
+import (
+	"fmt"
+	"io"
+	"reflect"
+	"testing"
+)
+
+type mockClient struct {
+}
+
+type mockReceiver struct {
+}
+
+func (r mockReceiver) WriteTo(w io.Writer) (n int64, err error) {
+	b := []byte("cloud-config file")
+	w.Write(b)
+	return int64(len(b)), nil
+}
+
+func (c mockClient) Receive(filename string, mode string) (io.WriterTo, error) {
+	if filename == "does-not-exist" {
+		return &mockReceiver{}, fmt.Errorf("does not exist")
+	}
+	return &mockReceiver{}, nil
+}
+
+var _ Client = (*mockClient)(nil)
+
+func TestNewDatasource(t *testing.T) {
+	for _, tt := range []struct {
+		root       string
+		expectHost string
+		expectPath string
+	}{
+		{
+			root:       "127.0.0.1/test/file.yaml",
+			expectHost: "127.0.0.1:69",
+			expectPath: "test/file.yaml",
+		},
+		{
+			root:       "127.0.0.1/test/file.yaml",
+			expectHost: "127.0.0.1:69",
+			expectPath: "test/file.yaml",
+		},
+	} {
+		ds := NewDatasource(tt.root)
+		if ds.host != tt.expectHost || ds.path != tt.expectPath {
+			t.Fatalf("bad host or path (%q): want host=%s, got %s, path=%s, got %s", tt.root, tt.expectHost, ds.host, tt.expectPath, ds.path)
+		}
+	}
+}
+
+func TestIsAvailable(t *testing.T) {
+	for _, tt := range []struct {
+		remoteFile *RemoteFile
+		expect     bool
+	}{
+		{
+			remoteFile: &RemoteFile{"1.2.3.4", "test", &mockClient{}, nil, nil},
+			expect:     true,
+		},
+		{
+			remoteFile: &RemoteFile{"1.2.3.4", "does-not-exist", &mockClient{}, nil, nil},
+			expect:     false,
+		},
+	} {
+		if tt.remoteFile.IsAvailable() != tt.expect {
+			t.Fatalf("expected remote file %s to be %v", tt.remoteFile.path, tt.expect)
+		}
+	}
+}
+
+func TestFetchUserdata(t *testing.T) {
+	rf := &RemoteFile{"1.2.3.4", "test", &mockClient{}, &mockReceiver{}, nil}
+	b, _ := rf.FetchUserdata()
+
+	expect := []byte("cloud-config file")
+
+	if len(b) != len(expect) || !reflect.DeepEqual(b, expect) {
+		t.Fatalf("expected length of buffer to be %d was %d. Expected %s, got %s", len(expect), len(b), string(expect), string(b))
+	}
+}
+
+func TestType(t *testing.T) {
+	rf := &RemoteFile{"1.2.3.4", "test", &mockClient{}, nil, nil}
+
+	if rf.Type() != "tftp" {
+		t.Fatalf("expected remote file Type() to return %s got %s", "tftp", rf.Type())
+	}
+}