Bump min go version to 1.18 && read build info from embedded binary

changeset/commit.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2018 The Knative Authors
+Copyright 2022 The Knative Authors
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -17,113 +17,66 @@ limitations under the License.
 package changeset
 
 import (
-	"bufio"
-	"fmt"
-	"io/ioutil"
-	"os"
-	"path/filepath"
+	"errors"
 	"regexp"
-	"strings"
+	"runtime/debug"
+	"strconv"
+	"sync"
 )
 
-const (
-	commitIDFile      = "HEAD"
-	koDataPathEnvName = "KO_DATA_PATH"
-	// packedRefsFile is a file containing a list of refs, used to compact the
-	// list of refs instead of storing them on the filesystem directly.
-	// See https://git-scm.com/docs/git-pack-refs
-	packedRefsFile = "packed-refs"
-)
+const Unknown = "unknown"
+
+var (
+	shaRegexp = regexp.MustCompile(`^[a-f0-9]{40,64}$`)
+	rev       string
+	err       error
+	once      sync.Once
 
-var commitIDRE = regexp.MustCompile(`^[a-f0-9]{40}$`)
+	// for testing
+	readBuildInfo = debug.ReadBuildInfo
+)
 
-// Get tries to fetch the first 7 digitals of GitHub commit ID from HEAD file in
-// KO_DATA_PATH. If it fails, it returns the error it gets.
+// Get returns the 'vcs.revision' property from the embedded build information
+// This function will return an error if value is not a valid Git SHA
+//
+// The result will have a '-dirty' suffix if the workspace was not clean
 func Get() (string, error) {
-	data, err := readFileFromKoData(commitIDFile)
-	if err != nil {
-		return "", err
+	once.Do(func() {
+		rev, err = get()
+	})
+
+	return rev, err
+}
+
+func get() (string, error) {
+	info, ok := readBuildInfo()
+	if !ok {
+		return "", errors.New("unable to read build info")
 	}
-	commitID := strings.TrimSpace(string(data))
-	if rID := strings.TrimPrefix(commitID, "ref: "); rID != commitID {
-		// First try to read from the direct ref file - e.g. refs/heads/main
-		data, err := readFileFromKoData(rID)
-		if err != nil {
-			if !os.IsNotExist(err) {
-				return "", err
-			}
-
-			// Ref file didn't exist - it might be contained in the packed-refs
-			// file.
-			var pferr error
-			data, pferr = findPackedRef(rID)
-			// Only return the sub-error if the packed-refs file exists, otherwise
-			// just let the original error return (e.g. treat it as if we didn't
-			// even attempt the operation). This is primarily to keep the error
-			// messages clean.
-			if pferr != nil {
-				if os.IsNotExist(pferr) {
-					return "", err
-				}
-				return "", pferr
-			}
+
+	var revision string
+	var modified bool
+
+	for _, s := range info.Settings {
+		switch s.Key {
+		case "vcs.revision":
+			revision = s.Value
+		case "vcs.modified":
+			modified, _ = strconv.ParseBool(s.Value)
 		}
-		commitID = strings.TrimSpace(string(data))
 	}
-	if commitIDRE.MatchString(commitID) {
-		return commitID[:7], nil
-	}
-	return "", fmt.Errorf("%q is not a valid GitHub commit ID", commitID)
-}
 
-// readFileFromKoData tries to read data as string from the file with given name
-// under KO_DATA_PATH then returns the content as string. The file is expected
-// to be wrapped into the container from /kodata by ko. If it fails, returns
-// the error it gets.
-func readFileFromKoData(filename string) ([]byte, error) {
-	f, err := koDataFile(filename)
-	if err != nil {
-		return nil, err
+	if revision == "" {
+		return Unknown, nil
 	}
-	defer f.Close()
-	return ioutil.ReadAll(f)
-}
 
-// readFileFromKoData tries to open the file with given name under KO_DATA_PATH.
-// The file is expected to be wrapped into the container from /kodata by ko.
-// If it fails, returns the error it gets.
-func koDataFile(filename string) (*os.File, error) {
-	koDataPath := os.Getenv(koDataPathEnvName)
-	if koDataPath == "" {
-		return nil, fmt.Errorf("%q does not exist or is empty", koDataPathEnvName)
+	if shaRegexp.MatchString(revision) {
+		revision = revision[:7]
 	}
-	return os.Open(filepath.Join(koDataPath, filename))
-}
 
-// findPackedRef searches the packed-ref file for ref values.
-// This can happen if the # of refs in a repo grows too much - git will try
-// and condense them into a file.
-// See https://git-scm.com/docs/git-pack-refs
-func findPackedRef(ref string) ([]byte, error) {
-	f, err := koDataFile(packedRefsFile)
-	if err != nil {
-		return nil, err
+	if modified {
+		revision += "-dirty"
 	}
-	defer f.Close()
-
-	scanner := bufio.NewScanner(f)
-	for scanner.Scan() {
-		// We only care about lines with `<commit> <ref>` pairs.
-		// Why this might happen:
-		// 1. Lines starting with ^ refer to unpeeled tag SHAs
-		// 	  (e.g. the commits pointed to by annotated tags)
-		s := strings.Split(scanner.Text(), " ")
-		if len(s) != 2 {
-			continue
-		}
-		if ref == s[1] {
-			return []byte(s[0]), nil
-		}
-	}
-	return nil, fmt.Errorf("%q ref not found in packed-refs", ref)
+
+	return revision, nil
 }

changeset/commit_test.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2018 The Knative Authors
+Copyright 2022 The Knative Authors
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -17,87 +17,81 @@ limitations under the License.
 package changeset
 
 import (
-	"errors"
-	"fmt"
+	"runtime/debug"
+	"sync"
 	"testing"
-)
 
-const (
-	nonCommittedHeadRef = "refs/heads/non_committed_branch"
-	testCommitID        = "a2d1bdf"
+	"github.com/google/go-cmp/cmp"
 )
 
-func TestReadFile(t *testing.T) {
-	tests := []struct {
-		name                      string
-		koDataPath                string
-		koDataPathEnvDoesNotExist bool
-		want                      string
-		wantErr                   bool
-		err                       error
+func TestGet(t *testing.T) {
+
+	cases := []struct {
+		name    string
+		info    *debug.BuildInfo
+		ok      bool
+		result  string
+		wantErr string
 	}{{
-		name:       "committed branch",
-		koDataPath: "testdata",
-		want:       testCommitID,
-	}, {
-		name:       "no refs link",
-		koDataPath: "testdata/noncommitted",
-		wantErr:    true,
-		err:        fmt.Errorf("open testdata/noncommitted/%s: no such file or directory", nonCommittedHeadRef),
-	}, {
-		name:       "with refs link",
-		koDataPath: "testdata/with-refs",
-		want:       testCommitID,
-	}, {
-		name:       "with bad content",
-		koDataPath: "testdata/garbage",
-		wantErr:    true,
-		err:        fmt.Errorf(`"garbage contents" is not a valid GitHub commit ID`),
-	}, {
-		name:       "KO_DATA_PATH is empty",
-		koDataPath: "",
-		wantErr:    true,
-		err:        fmt.Errorf("%q does not exist or is empty", koDataPathEnvName),
+		name:    "info fails",
+		ok:      false,
+		wantErr: "unable to read build info",
 	}, {
-		name:                      "KO_DATA_PATH does not exist",
-		koDataPath:                "",
-		wantErr:                   true,
-		koDataPathEnvDoesNotExist: true,
-		err:                       fmt.Errorf("%q does not exist or is empty", koDataPathEnvName),
+		name:   "missing revision",
+		ok:     true,
+		info:   &debug.BuildInfo{},
+		result: Unknown,
 	}, {
-		name:       "HEAD file does not exist",
-		koDataPath: "testdata/nonexisting",
-		wantErr:    true,
-		err:        errors.New("open testdata/nonexisting/HEAD: no such file or directory"),
+		name: "SHA1 revision is truncated",
+		ok:   true,
+		info: &debug.BuildInfo{
+			Settings: []debug.BuildSetting{{
+				Key: "vcs.revision", Value: "3666ce749d32abe7be0528380c8c05a4282cb733",
+			}},
+		},
+		result: "3666ce7",
 	}, {
-		name:       "packed-ref",
-		koDataPath: "testdata/packed-refs",
-		want:       testCommitID,
+		name: "SHA256 revision is truncated",
+		ok:   true,
+		info: &debug.BuildInfo{
+			Settings: []debug.BuildSetting{{
+				Key: "vcs.revision", Value: "2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824",
+			}},
+		},
+		result: "2cf24db",
 	}, {
-		name:       "no refs with packed-ref",
-		koDataPath: "testdata/noncommited-packed-refs",
-		wantErr:    true,
-		err:        fmt.Errorf("%q ref not found in packed-refs", nonCommittedHeadRef),
+		name: "modified workspace results in -dirty suffix",
+		ok:   true,
+		info: &debug.BuildInfo{
+			Settings: []debug.BuildSetting{{
+				Key: "vcs.revision", Value: "3666ce749d32abe7be0528380c8c05a4282cb733",
+			}, {
+				Key: "vcs.modified", Value: "true",
+			}},
+		},
+		result: "3666ce7-dirty",
 	}}
-	for _, test := range tests {
-		t.Run(test.name, func(t *testing.T) {
-			if !test.koDataPathEnvDoesNotExist {
-				t.Setenv(koDataPathEnvName, test.koDataPath)
-			}
-
-			got, err := Get()
 
-			if (err != nil) != test.wantErr {
-				t.Error("Get() =", err)
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			once = sync.Once{}
+			readBuildInfo = func() (info *debug.BuildInfo, ok bool) {
+				return c.info, c.ok
 			}
-			if !test.wantErr {
-				if test.want != got {
-					t.Errorf("wanted %q but got %q", test.want, got)
-				}
-			} else {
-				if err == nil || err.Error() != test.err.Error() {
-					t.Errorf("wanted error %v but got: %v", test.err, err)
+
+			val, err := Get()
+			if c.wantErr == "" && err != nil {
+				t.Fatal("unexpected error", err)
+			} else if c.wantErr != "" && err != nil {
+				if diff := cmp.Diff(c.wantErr, err.Error()); diff != "" {
+					t.Fatalf("error doesn't match expected: %s", diff)
 				}
+			} else if c.wantErr != "" && err == nil {
+				t.Fatalf("expected error %q but was nil", c.wantErr)
+			}
+
+			if diff := cmp.Diff(c.result, val); diff != "" {
+				t.Errorf("result doesn't match expected: %s", diff)
 			}
 		})
 	}

changeset/doc.go

@@ -14,10 +14,6 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-// Package changeset provides Knative utilities for fetching GitHub Commit ID
-// from kodata directory. It requires GitHub HEAD file to be linked into
-// Knative component source code via the following command:
-//   ln -s -r .git/HEAD ./cmd/<knative-component-name>/kodata/
-// Then ko will build this file into $KO_DATA_PATH when building the container
-// for a Knative component.
+// Package changeset returns version control info that was embedded in the
+// golang binary
 package changeset

go.mod

@@ -1,6 +1,6 @@
 module knative.dev/pkg
 
-go 1.17
+go 1.18
 
 require (
 	cloud.google.com/go v0.98.0