Add a "deploy" command

deploy/deploy.go

@@ -0,0 +1,535 @@
+// Copyright 2019 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package deploy
+
+import (
+	"bytes"
+	"compress/gzip"
+	"context"
+	"crypto/md5"
+	"fmt"
+	"golang.org/x/text/unicode/norm"
+	"io"
+	"mime"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"sync"
+
+	"github.com/dustin/go-humanize"
+	"github.com/gohugoio/hugo/config"
+	"github.com/pkg/errors"
+	"github.com/spf13/afero"
+	jww "github.com/spf13/jwalterweatherman"
+
+	"gocloud.dev/blob"
+	_ "gocloud.dev/blob/azureblob" // import
+	_ "gocloud.dev/blob/fileblob"  // import
+	_ "gocloud.dev/blob/gcsblob"   // import
+	_ "gocloud.dev/blob/s3blob"    // import
+)
+
+// Deployer supports deploying the site to target cloud providers.
+type Deployer struct {
+	localFs afero.Fs
+
+	targetURL  string     // the Go Cloud blob URL to deploy to
+	matchers   []*matcher // matchers to apply to uploaded files
+	quiet      bool       // true reduces STDOUT
+	confirm    bool       // true enables confirmation before making changes
+	dryRun     bool       // true skips conformations and prints changes instead of applying them
+	force      bool       // true forces upload of all files
+	maxDeletes int        // caps the # of files to delete; -1 to disable
+}
+
+// New constructs a new *Deployer.
+func New(cfg config.Provider, localFs afero.Fs) (*Deployer, error) {
+	target := cfg.GetString("target")
+
+	// Load the [deployment] section of the config.
+	dcfg, err := decodeConfig(cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	// Find the target to deploy to.
+	var targetURL string
+	for _, t := range dcfg.Targets {
+		if t.Name == target {
+			targetURL = t.URL
+		}
+	}
+	if targetURL == "" {
+		return nil, fmt.Errorf("deployment target %q not found", target)
+	}
+	return &Deployer{
+		localFs:    localFs,
+		targetURL:  targetURL,
+		matchers:   dcfg.Matchers,
+		quiet:      cfg.GetBool("quiet"),
+		confirm:    cfg.GetBool("confirm"),
+		dryRun:     cfg.GetBool("dryRun"),
+		force:      cfg.GetBool("force"),
+		maxDeletes: cfg.GetInt("maxDeletes"),
+	}, nil
+}
+
+// Deploy deploys the site to a target.
+func (d *Deployer) Deploy(ctx context.Context) error {
+	// TODO: This opens the root path in the bucket/container.
+	// Consider adding support for targeting a subdirectory.
+	bucket, err := blob.OpenBucket(ctx, d.targetURL)
+	if err != nil {
+		return err
+	}
+
+	// Load local files from the source directory.
+	local, err := walkLocal(d.localFs, d.matchers)
+	if err != nil {
+		return err
+	}
+	jww.INFO.Printf("Found %d local files.\n", len(local))
+
+	// Load remote files from the target.
+	remote, err := walkRemote(ctx, bucket)
+	if err != nil {
+		return err
+	}
+	jww.INFO.Printf("Found %d remote files.\n", len(remote))
+
+	// Diff local vs remote to see what changes need to be applied.
+	uploads, deletes := findDiffs(local, remote, d.force)
+	if err != nil {
+		return err
+	}
+	if len(uploads)+len(deletes) == 0 {
+		if !d.quiet {
+			jww.FEEDBACK.Println("No changes required.")
+		}
+		return nil
+	}
+	if !d.quiet {
+		jww.FEEDBACK.Println(summarizeChanges(uploads, deletes))
+	}
+
+	// Ask for confirmation before proceeding.
+	if d.confirm && !d.dryRun {
+		fmt.Printf("Continue? (Y/n) ")
+		var confirm string
+		if _, err := fmt.Scanln(&confirm); err != nil {
+			return err
+		}
+		if confirm != "" && confirm[0] != 'y' && confirm[0] != 'Y' {
+			return errors.New("aborted")
+		}
+	}
+
+	// Apply the changes in parallel, using an inverted worker
+	// pool (https://www.youtube.com/watch?v=5zXAHh5tJqQ&t=26m58s).
+	// sem prevents more than nParallel concurrent goroutines.
+	const nParallel = 10
+	sem := make(chan struct{}, nParallel)
+	var errs []error
+	var errMu sync.Mutex // protects errs
+
+	for _, upload := range uploads {
+		if d.dryRun {
+			if !d.quiet {
+				jww.FEEDBACK.Printf("[DRY RUN] Would upload: %v\n", upload)
+			}
+			continue
+		}
+
+		// TODO: Add a progress indicator, as this can take a while
+		// depending on the number of files, upload speed, and size of the
+		// site.
+
+		sem <- struct{}{}
+		go func(upload *fileToUpload) {
+			if err := doSingleUpload(ctx, bucket, upload); err != nil {
+				errMu.Lock()
+				defer errMu.Unlock()
+				errs = append(errs, err)
+			}
+			<-sem
+		}(upload)
+	}
+
+	if d.maxDeletes != -1 && len(deletes) > d.maxDeletes {
+		jww.WARN.Printf("Skipping %d deletes because it is more than --maxDeletes (%d). If this is expected, set --maxDeletes to a larger number, or -1 to disable this check.\n", len(deletes), d.maxDeletes)
+	} else {
+		for _, del := range deletes {
+			if d.dryRun {
+				if !d.quiet {
+					jww.FEEDBACK.Printf("[DRY RUN] Would delete %s\n", del)
+				}
+				continue
+			}
+			sem <- struct{}{}
+			go func(del string) {
+				jww.INFO.Printf("Deleting %s...\n", del)
+				if err := bucket.Delete(ctx, del); err != nil {
+					errMu.Lock()
+					defer errMu.Unlock()
+					errs = append(errs, err)
+				}
+				<-sem
+			}(del)
+		}
+	}
+	// Wait for all uploads/deletes to finish.
+	for n := nParallel; n > 0; n-- {
+		sem <- struct{}{}
+	}
+	if len(errs) > 0 {
+		if !d.quiet {
+			jww.FEEDBACK.Printf("Encountered %d errors.\n", len(errs))
+		}
+		return errs[0]
+	}
+	if !d.quiet {
+		jww.FEEDBACK.Println("Success!")
+	}
+
+	// TODO: Add support for CloudFront invalidation similar to s3deploy,
+	// and possibly similar functionality for other providers.
+
+	return nil
+}
+
+// summarizeChanges creates a text description of the proposed changes.
+func summarizeChanges(uploads []*fileToUpload, deletes []string) string {
+	uploadSize := int64(0)
+	for _, u := range uploads {
+		uploadSize += u.Local.UploadSize
+	}
+	return fmt.Sprintf("Identified %d file(s) to upload, totaling %s, and %d file(s) to delete.", len(uploads), humanize.Bytes(uint64(uploadSize)), len(deletes))
+}
+
+// doSingleUpload executes a single file upload.
+func doSingleUpload(ctx context.Context, bucket *blob.Bucket, upload *fileToUpload) error {
+	jww.INFO.Printf("Uploading %v...\n", upload)
+	opts := &blob.WriterOptions{
+		CacheControl:    upload.Local.CacheControl(),
+		ContentEncoding: upload.Local.ContentEncoding(),
+		ContentType:     upload.Local.ContentType(),
+	}
+	w, err := bucket.NewWriter(ctx, upload.Local.Path, opts)
+	if err != nil {
+		return err
+	}
+	_, err = io.Copy(w, upload.Local.UploadContentReader)
+	if err != nil {
+		return err
+	}
+	if err := w.Close(); err != nil {
+		return err
+	}
+	return nil
+}
+
+// localFile represents a local file from the source. Use newLocalFile to
+// construct one.
+type localFile struct {
+	// Path is the relative path to the file.
+	Path string
+	// UploadSize is the size of the content to be uploaded. It may not
+	// be the same as the local file size if the content will be
+	// gzipped before upload.
+	UploadSize int64
+	// UploadContentReader reads the content to be uploaded. Again,
+	// it may not be the same as the local file content due to gzipping.
+	UploadContentReader io.Reader
+
+	fs      afero.Fs
+	matcher *matcher
+	md5     []byte // cache
+}
+
+// newLocalFile initializes a *localFile.
+func newLocalFile(fs afero.Fs, path string, m *matcher) (*localFile, error) {
+	r, size, err := contentToUpload(fs, path, m)
+	if err != nil {
+		return nil, err
+	}
+	return &localFile{
+		Path:                path,
+		UploadSize:          size,
+		UploadContentReader: r,
+		fs:                  fs,
+		matcher:             m,
+	}, nil
+}
+
+// contentToUpload returns an io.Reader and size for the content to be uploaded
+// from path. It applies gzip encoding if needed.
+func contentToUpload(fs afero.Fs, path string, m *matcher) (io.Reader, int64, error) {
+	f, err := fs.Open(path)
+	if err != nil {
+		return nil, 0, err
+	}
+	info, err := f.Stat()
+	if err != nil {
+		return nil, 0, err
+	}
+	r := io.Reader(f)
+	size := info.Size()
+	if m != nil && m.Gzip {
+		var b bytes.Buffer
+		gz := gzip.NewWriter(&b)
+		io.Copy(gz, f)
+		gz.Close()
+		r = &b
+		size = int64(b.Len())
+	}
+	return r, size, nil
+}
+
+// CacheControl returns the Cache-Control header to use for lf, based on the
+// first matching matcher (if any).
+func (lf *localFile) CacheControl() string {
+	if lf.matcher == nil {
+		return ""
+	}
+	return lf.matcher.CacheControl
+}
+
+// ContentEncoding returns the Content-Encoding header to use for lf, based
+// on the matcher's Content-Encoding and Gzip fields.
+func (lf *localFile) ContentEncoding() string {
+	if lf.matcher == nil {
+		return ""
+	}
+	if lf.matcher.Gzip {
+		return "gzip"
+	}
+	return lf.matcher.ContentEncoding
+}
+
+// ContentType returns the Content-Type header to use for lf.
+// It first checks if there's a Content-Type header configured via a matching
+// matcher; if not, it tries to generate one based on the filename extension.
+// If this fails, the Content-Type will be the empty string. In this case, Go
+// Cloud will automatically try to infer a Content-Type based on the file
+// content.
+func (lf *localFile) ContentType() string {
+	if lf.matcher != nil && lf.matcher.ContentType != "" {
+		return lf.matcher.ContentType
+	}
+	// TODO: Hugo has a MediaType and a MediaTypes list and also a concept
+	// of custom MIME types.
+	// Use 1) The matcher 2) Hugo's MIME types 3) TypeByExtension.
+	return mime.TypeByExtension(filepath.Ext(lf.Path))
+}
+
+// Force returns true if the file should be forced to re-upload based on the
+// matching matcher.
+func (lf *localFile) Force() bool {
+	return lf.matcher != nil && lf.matcher.Force
+}
+
+// MD5 returns an MD5 hash of the content to be uploaded.
+func (lf *localFile) MD5() []byte {
+	if len(lf.md5) > 0 {
+		return lf.md5
+	}
+	// We can't use lf.UploadContentReader directly because if there's a
+	// delta we'll want to read it again later, and we have no way of
+	// resetting the reader. So, create a new one.
+	r, _, err := contentToUpload(lf.fs, lf.Path, lf.matcher)
+	if err != nil {
+		return nil
+	}
+	h := md5.New()
+	if _, err := io.Copy(h, r); err != nil {
+		return nil
+	}
+	lf.md5 = h.Sum(nil)
+	return lf.md5
+}
+
+// walkLocal walks the source directory and returns a flat list of files.
+func walkLocal(fs afero.Fs, matchers []*matcher) (map[string]*localFile, error) {
+	retval := map[string]*localFile{}
+	err := afero.Walk(fs, "", func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			// Skip hidden directories.
+			if path != "" && strings.HasPrefix(info.Name(), ".") {
+				return filepath.SkipDir
+			}
+			return nil
+		}
+
+		// .DS_Store is an internal MacOS attribute file; skip it.
+		if info.Name() == ".DS_Store" {
+			return nil
+		}
+
+		// When a file system is HFS+, its filepath is in NFD form.
+		if runtime.GOOS == "darwin" {
+			path = norm.NFC.String(path)
+		}
+
+		// Find the first matching matcher (if any).
+		var m *matcher
+		for _, cur := range matchers {
+			if cur.Matches(path) {
+				m = cur
+				break
+			}
+		}
+		lf, err := newLocalFile(fs, path, m)
+		if err != nil {
+			return err
+		}
+		retval[path] = lf
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return retval, nil
+}
+
+// walkRemote walks the target bucket and returns a flat list.
+func walkRemote(ctx context.Context, bucket *blob.Bucket) (map[string]*blob.ListObject, error) {
+	retval := map[string]*blob.ListObject{}
+	iter := bucket.List(nil)
+	for {
+		obj, err := iter.Next(ctx)
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return nil, err
+		}
+		retval[obj.Key] = obj
+	}
+	return retval, nil
+}
+
+// uploadReason is an enum of reasons why a file must be uploaded.
+type uploadReason string
+
+const (
+	reasonUnknown    uploadReason = "unknown"
+	reasonNotFound   uploadReason = "not found at target"
+	reasonForce      uploadReason = "--force"
+	reasonSize       uploadReason = "size differs"
+	reasonMD5Differs uploadReason = "md5 differs"
+	reasonMD5Missing uploadReason = "remote md5 missing"
+)
+
+// fileToUpload represents a single local file that should be uploaded to
+// the target.
+type fileToUpload struct {
+	Local  *localFile
+	Reason uploadReason
+}
+
+func (u *fileToUpload) String() string {
+	details := []string{humanize.Bytes(uint64(u.Local.UploadSize))}
+	if s := u.Local.CacheControl(); s != "" {
+		details = append(details, fmt.Sprintf("Cache-Control: %q", s))
+	}
+	if s := u.Local.ContentEncoding(); s != "" {
+		details = append(details, fmt.Sprintf("Content-Encoding: %q", s))
+	}
+	if s := u.Local.ContentType(); s != "" {
+		details = append(details, fmt.Sprintf("Content-Type: %q", s))
+	}
+	return fmt.Sprintf("%s (%s): %v", u.Local.Path, strings.Join(details, ", "), u.Reason)
+}
+
+// findDiffs diffs localFiles vs remoteFiles to see what changes should be
+// applied to the remote target. It returns a slice of *fileToUpload and a
+// slice of paths for files to delete.
+func findDiffs(localFiles map[string]*localFile, remoteFiles map[string]*blob.ListObject, force bool) ([]*fileToUpload, []string) {
+	var uploads []*fileToUpload
+	var deletes []string
+
+	// TODO: Do we need to remap file delimiters, e.g. on Windows?
+
+	found := map[string]bool{}
+	for path, lf := range localFiles {
+		upload := false
+		reason := reasonUnknown
+
+		if remoteFile, ok := remoteFiles[path]; ok {
+			// The file exists in remote. Let's see if we need to upload it anyway.
+
+			// TODO: We don't register a diff if the metadata (e.g., Content-Type
+			// header) has changed. This would be difficult/expensive to detect; some
+			// providers return metadata along with their "List" result, but others
+			// (notably AWS S3) do not, so gocloud.dev's blob.Bucket doesn't expose
+			// it in the list result. It would require a separate request per blob
+			// to fetch. At least for now, we work around this by documenting it and
+			// providing a "force" flag (to re-upload everything) and a "force" bool
+			// per matcher (to re-upload all files in a matcher whose headers may have
+			// changed).
+			// Idea: extract a sample set of 1 file per extension + 1 file per matcher
+			// and check those files?
+			if force {
+				upload = true
+				reason = reasonForce
+			} else if lf.Force() {
+				upload = true
+				reason = reasonForce
+			} else if lf.UploadSize != remoteFile.Size {
+				upload = true
+				reason = reasonSize
+			} else if len(remoteFile.MD5) == 0 {
+				// TODO: This can happen if the remote provider doesn't return an MD5
+				// hash for the blob from their "list" command. This is common for
+				// some providers (e.g., fileblob, which uses the local filesystem),
+				// but not for the biggest Cloud providers (S3, GCS, Azure). Although,
+				// it can happen for S3 if the blob was originally uploaded as a
+				// multi-part upload (shouldn't happen when using "hugo deploy").
+				// For now, we treat this as an MD5 mismatch and re-upload. An
+				// alternative would be to read entire the remote blob and compute the
+				// MD5 hash.
+				upload = true
+				reason = reasonMD5Missing
+			} else if !bytes.Equal(lf.MD5(), remoteFile.MD5) {
+				upload = true
+				reason = reasonMD5Differs
+			} else {
+				// Nope! Leave uploaded = false.
+			}
+			found[path] = true
+		} else {
+			// The file doesn't exist in remote.
+			upload = true
+			reason = reasonNotFound
+		}
+		if upload {
+			jww.DEBUG.Printf("%s needs to be uploaded: %v\n", path, reason)
+			uploads = append(uploads, &fileToUpload{lf, reason})
+		} else {
+			jww.DEBUG.Printf("%s exists at target and does not need to be uploaded", path)
+		}
+	}
+
+	// Remote files that weren't found locally should be deleted.
+	for path := range remoteFiles {
+		if !found[path] {
+			deletes = append(deletes, path)
+		}
+	}
+	return uploads, deletes
+}