Add pipe package, streamline error handling in vcs

pipe/pipe.go

@@ -0,0 +1,27 @@
+package pipe
+
+// Op is the common pipe operation. Can be composed into Ops and run as a single unit
+type Op interface {
+	Do() error
+}
+
+// OpFunc can easily wrap an anonymous function into an Op
+type OpFunc func() error
+
+// Do implements the Op interface
+func (o OpFunc) Do() error {
+	return o()
+}
+
+// Ops can run a slice of Op's in series, stopping on the first error
+type Ops []Op
+
+// Do implements the Op interface
+func (ops Ops) Do() error {
+	for _, op := range ops {
+		if err := op.Do(); err != nil {
+			return err
+		}
+	}
+	return nil
+}

pipe/pipe_test.go

@@ -0,0 +1,54 @@
+package pipe
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestOpFuncDo(t *testing.T) {
+	t.Run("no error", func(t *testing.T) {
+		op := OpFunc(func() error {
+			return nil
+		})
+		assert.NoError(t, op.Do())
+	})
+
+	t.Run("error", func(t *testing.T) {
+		someErr := errors.New("some error")
+		op := OpFunc(func() error {
+			return someErr
+		})
+		assert.Equal(t, someErr, op.Do())
+	})
+}
+
+func TestOpsDo(t *testing.T) {
+	nilOp := OpFunc(func() error {
+		return nil
+	})
+	someErr := errors.New("some error")
+	errOp := OpFunc(func() error {
+		return someErr
+	})
+
+	detectOp := func(ran *bool) Op {
+		return OpFunc(func() error {
+			*ran = true
+			return nil
+		})
+	}
+
+	t.Run("no errors", func(t *testing.T) {
+		var ranLast bool
+		assert.NoError(t, Ops{nilOp, nilOp, nilOp, detectOp(&ranLast)}.Do())
+		assert.True(t, ranLast)
+	})
+
+	t.Run("stops on first error", func(t *testing.T) {
+		var ranAfterError bool
+		assert.Equal(t, someErr, Ops{nilOp, errOp, detectOp(&ranAfterError), nilOp}.Do())
+		assert.False(t, ranAfterError)
+	})
+}

vcs/vcs.go

@@ -7,6 +7,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/johnstarich/sage/pipe"
 	"github.com/pkg/errors"
 	"gopkg.in/src-d/go-git.v4"
 	"gopkg.in/src-d/go-git.v4/plumbing"
@@ -42,40 +43,46 @@ type syncRepo struct {
 }
 
 func initVCS(path string) (*git.Repository, error) {
-	repo, err := git.PlainInit(path, false)
-	if err != nil {
-		return nil, err
-	}
-	tree, err := repo.Worktree()
-	if err != nil {
-		return nil, err
-	}
-
-	status, err := tree.Status()
-	if err != nil {
-		return nil, err
-	}
-
-	added := false
-	for file, stat := range status {
-		// add any untracked files, excluding hidden and tmp files
-		if stat.Worktree == git.Untracked && !strings.HasPrefix(file, ".") && !strings.HasSuffix(file, ".tmp") {
-			_, err := tree.Add(file)
-			if err != nil {
-				return nil, err
+	var err error
+	var repo *git.Repository
+	var tree *git.Worktree
+	var status git.Status
+	return repo, pipe.Ops{
+		pipe.OpFunc(func() error {
+			repo, err = git.PlainInit(path, false)
+			return err
+		}),
+		pipe.OpFunc(func() error {
+			tree, err = repo.Worktree()
+			return err
+		}),
+		pipe.OpFunc(func() error {
+			status, err = tree.Status()
+			return err
+		}),
+		pipe.OpFunc(func() error {
+			var ops pipe.Ops
+			added := false
+			for file, stat := range status {
+				// add any untracked files, excluding hidden and tmp files
+				if stat.Worktree == git.Untracked && !strings.HasPrefix(file, ".") && !strings.HasSuffix(file, ".tmp") {
+					fileCopy := file
+					ops = append(ops, pipe.OpFunc(func() error {
+						_, err := tree.Add(fileCopy)
+						return err
+					}))
+					added = true
+				}
 			}
-			added = true
-		}
-	}
-	if added {
-		_, err := tree.Commit("Initial commit", &git.CommitOptions{
-			Author: sageAuthor(),
-		})
-		if err != nil {
-			return nil, err
-		}
-	}
-	return repo, nil
+			if added {
+				ops = append(ops, pipe.OpFunc(func() error {
+					_, err := tree.Commit("Initial commit", &git.CommitOptions{Author: sageAuthor()})
+					return err
+				}))
+			}
+			return ops.Do()
+		}),
+	}.Do()
 }
 
 func sageAuthor() *object.Signature {

vcs/vcs_test.go

@@ -3,6 +3,7 @@ package vcs
 import (
 	"io/ioutil"
 	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -11,18 +12,22 @@ import (
 	"gopkg.in/src-d/go-git.v4/plumbing/object"
 )
 
+const testDBPath = "./testdb"
+
+func cleanupTestDB(t *testing.T) {
+	t.Helper()
+	require.NoError(t, os.RemoveAll(testDBPath))
+}
+
 func TestOpen(t *testing.T) {
-	cleanup := func() {
-		require.NoError(t, os.RemoveAll("./testdb"))
-	}
-	cleanup()
-	defer cleanup()
-	err := os.MkdirAll("./testdb", 0750)
+	cleanupTestDB(t)
+	defer cleanupTestDB(t)
+	err := os.MkdirAll(testDBPath, 0750)
 	require.NoError(t, err)
-	err = ioutil.WriteFile("./testdb/bucket.json", []byte(`{}`), 0750)
+	err = ioutil.WriteFile(filepath.Join(testDBPath, "bucket.json"), []byte(`{}`), 0750)
 	require.NoError(t, err)
 
-	repoInt, err := Open("./testdb")
+	repoInt, err := Open(testDBPath)
 	require.NoError(t, err)
 	require.IsType(t, &syncRepo{}, repoInt)
 
@@ -49,21 +54,29 @@ func TestOpen(t *testing.T) {
 	assert.Equal(t, 1, count)
 }
 
+func TestOpenMkdirErr(t *testing.T) {
+	cleanupTestDB(t)
+	defer cleanupTestDB(t)
+
+	err := ioutil.WriteFile(testDBPath, []byte(`I'm not a database!`), 0750)
+	require.NoError(t, err)
+	_, err = Open(testDBPath)
+	require.Error(t, err)
+	assert.Equal(t, "mkdir testdb: not a directory", err.Error())
+}
+
 func TestCommitFiles(t *testing.T) {
-	cleanup := func() {
-		require.NoError(t, os.RemoveAll("./testdb"))
-	}
-	cleanup()
-	defer cleanup()
+	cleanupTestDB(t)
+	defer cleanupTestDB(t)
 
-	repoInt, err := Open("./testdb")
+	repoInt, err := Open(testDBPath)
 	require.NoError(t, err)
 	require.IsType(t, &syncRepo{}, repoInt)
 	repo := repoInt.(*syncRepo)
 
 	err = repo.CommitFiles(func() error {
-		return ioutil.WriteFile("./testdb/some file.txt", []byte("hello world"), 0750)
-	}, "add some file", "./testdb/some file.txt")
+		return ioutil.WriteFile(filepath.Join(testDBPath, "some file.txt"), []byte("hello world"), 0750)
+	}, "add some file", filepath.Join(testDBPath, "some file.txt"))
 	require.NoError(t, err)
 
 	getCount := func() int {
@@ -81,27 +94,24 @@ func TestCommitFiles(t *testing.T) {
 	assert.Equal(t, 1, getCount())
 
 	err = repo.CommitFiles(func() error {
-		return ioutil.WriteFile("./testdb/some other file.txt", []byte("hello world"), 0750)
-	}, "add some other file", "./testdb/some other file.txt")
+		return ioutil.WriteFile(filepath.Join(testDBPath, "some other file.txt"), []byte("hello world"), 0750)
+	}, "add some other file", filepath.Join(testDBPath, "some other file.txt"))
 	require.NoError(t, err)
 	assert.Equal(t, 2, getCount())
 }
 
 func TestCommitNoChanges(t *testing.T) {
-	cleanup := func() {
-		require.NoError(t, os.RemoveAll("./testdb"))
-	}
-	cleanup()
-	defer cleanup()
+	cleanupTestDB(t)
+	defer cleanupTestDB(t)
 
-	repoInt, err := Open("./testdb")
+	repoInt, err := Open(testDBPath)
 	require.NoError(t, err)
 	require.IsType(t, &syncRepo{}, repoInt)
 	repo := repoInt.(*syncRepo)
 
 	err = repo.CommitFiles(func() error {
-		return ioutil.WriteFile("./testdb/some file.txt", []byte("hello world"), 0750)
-	}, "add some file", "./testdb/some file.txt")
+		return ioutil.WriteFile(filepath.Join(testDBPath, "some file.txt"), []byte("hello world"), 0750)
+	}, "add some file", filepath.Join(testDBPath, "some file.txt"))
 	require.NoError(t, err)
 
 	getCount := func() int {
@@ -118,7 +128,7 @@ func TestCommitNoChanges(t *testing.T) {
 	}
 	assert.Equal(t, 1, getCount())
 
-	err = repo.CommitFiles(func() error { return nil }, "add same file", "./testdb/some file.txt")
+	err = repo.CommitFiles(func() error { return nil }, "add same file", filepath.Join(testDBPath, "some file.txt"))
 	require.NoError(t, err)
 	assert.Equal(t, 1, getCount(), "no commit should be made for unchanged file")
 }