feat: Adding a preserve mtime feature to copy_to_directory and copy_directory

e2e/smoke/BUILD.bazel

@@ -99,3 +99,28 @@ bats_test(
         "basic.bats",
     ],
 )
+
+copy_to_directory(
+    name = "copy_to_directory_mtime_case",
+    srcs = ["d"],
+    out = "copy_to_directory_mtime_out",
+    preserve_mtime = True,
+)
+
+copy_directory(
+    name = "copy_directory_mtime_case",
+    src = "d",
+    out = "copy_directory_mtime_out",
+    preserve_mtime = True,
+)
+
+sh_test(
+    name = "test_preserve_mtime",
+    srcs = ["test_preserve_mtime.sh"],
+    data = [
+        "d",
+        ":copy_to_directory_mtime_case",
+        ":copy_directory_mtime_case",
+    ],
+    size = "small",
+)

e2e/smoke/test_preserve_mtime.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+function main {
+    compareMTimes d/1 copy_to_directory_mtime_out/d/1
+    compareMTimes d/1 copy_directory_mtime_out/1
+}
+
+function compareMTimes {
+    local originalFile="$1"
+    local copiedFile="$2"
+
+    local mtimeOriginal
+    mtimeOriginal="$(stat --dereference --format=%y "$originalFile")"
+
+    local mtimeCopy
+    mtimeCopy="$(stat --dereference --format=%y "$copiedFile")"
+
+    if [[ "$mtimeOriginal" != "$mtimeCopy" ]]; then
+        echo "Preserve mtime test failed. Modify times do not match for $originalFile and $copiedFile"
+        echo "  Original modify time: $mtimeOriginal"
+        echo "  Copied modify time:   $mtimeCopy"
+        return 1
+    fi
+
+    echo "Preserve mtime test passed for $originalFile and $copiedFile"
+}
+
+main "$@"

lib/private/copy_directory.bzl

@@ -12,7 +12,8 @@ def copy_directory_bin_action(
         dst,
         copy_directory_bin,
         hardlink = "auto",
-        verbose = False):
+        verbose = False,
+        preserve_mtime = False):
     """Factory function that creates an action to copy a directory from src to dst using a tool binary.
 
     The tool binary will typically be the `@aspect_bazel_lib//tools/copy_directory` `go_binary`
@@ -35,6 +36,8 @@ def copy_directory_bin_action(
             See copy_directory rule documentation for more details.
 
         verbose: If true, prints out verbose logs to stdout
+
+        preserve_mtime: If true, preserve the modified time from the source.
     """
     args = [
         src.path,
@@ -48,6 +51,9 @@ def copy_directory_bin_action(
     elif hardlink == "auto" and not src.is_source:
         args.append("--hardlink")
 
+    if preserve_mtime:
+        args.append("--preserve-mtime")
+
     ctx.actions.run(
         inputs = [src],
         outputs = [dst],
@@ -71,6 +77,7 @@ def _copy_directory_impl(ctx):
         copy_directory_bin = copy_directory_bin,
         hardlink = ctx.attr.hardlink,
         verbose = ctx.attr.verbose,
+        preserve_mtime = ctx.attr.preserve_mtime,
     )
 
     return [
@@ -93,6 +100,10 @@ _copy_directory = rule(
             default = "auto",
         ),
         "verbose": attr.bool(),
+        "preserve_mtime": attr.bool(
+            doc = "If True, the last modified time of copied files is preserved.",
+            default = False,
+        ),
         # use '_tool' attribute for development only; do not commit with this attribute active since it
         # propagates a dependency on rules_go which would be breaking for users
         # "_tool": attr.label(

lib/private/copy_to_directory.bzl

@@ -205,6 +205,7 @@ removed from sources files.
 - `off`: all files are copied
 - `on`: hardlinks are used for all files (not recommended)
     """,
+    "preserve_mtime": """If True, the last modified time of copied files is preserved.""",
     # verbose
     "verbose": """If true, prints out verbose logs to stdout""",
 }
@@ -251,6 +252,10 @@ _copy_to_directory_attr = {
         default = "auto",
         doc = _copy_to_directory_attr_doc["hardlink"],
     ),
+    "preserve_mtime": attr.bool(
+        default = False,
+        doc = _copy_to_directory_attr_doc["preserve_mtime"],
+    ),
     "verbose": attr.bool(
         doc = _copy_to_directory_attr_doc["verbose"],
     ),
@@ -285,6 +290,7 @@ def _copy_to_directory_impl(ctx):
         replace_prefixes = ctx.attr.replace_prefixes,
         allow_overwrites = ctx.attr.allow_overwrites,
         hardlink = ctx.attr.hardlink,
+        preserve_mtime = ctx.attr.preserve_mtime,
         verbose = ctx.attr.verbose,
     )
 
@@ -324,6 +330,7 @@ def copy_to_directory_bin_action(
         replace_prefixes = {},
         allow_overwrites = False,
         hardlink = "auto",
+        preserve_mtime = False,
         verbose = False):
     """Factory function to copy files to a directory using a tool binary.
 
@@ -382,6 +389,8 @@ def copy_to_directory_bin_action(
 
             See copy_to_directory rule documentation for more details.
 
+        preserve_mtime: If true, preserve the modified time from the source.
+
         verbose: If true, prints out verbose logs to stdout
     """
 
@@ -472,6 +481,7 @@ def copy_to_directory_bin_action(
         "include_srcs_patterns": include_srcs_patterns,
         "replace_prefixes": replace_prefixes,
         "root_paths": root_paths,
+        "preserve_mtime": preserve_mtime,
         "verbose": verbose,
     }
 

tools/common/copy.go

@@ -7,6 +7,7 @@ import (
 	"log"
 	"os"
 	"sync"
+	"time"
 )
 
 // From https://opensource.com/article/18/6/copying-files-go
@@ -27,7 +28,7 @@ func CopyFile(src string, dst string) error {
 }
 
 func Copy(opts CopyOpts) {
-	if !opts.info.Mode().IsRegular() {
+	if !opts.srcInfo.Mode().IsRegular() {
 		log.Fatalf("%s is not a regular file", opts.src)
 	}
 
@@ -79,6 +80,14 @@ func Copy(opts CopyOpts) {
 	if err != nil {
 		log.Fatal(err)
 	}
+
+	if opts.preserveMTime {
+		accessTime := time.Now()
+		err := os.Chtimes(opts.dst, accessTime, opts.srcInfo.ModTime())
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
 }
 
 type CopyWorker struct {
@@ -97,12 +106,13 @@ func (w *CopyWorker) Run(wg *sync.WaitGroup) {
 }
 
 type CopyOpts struct {
-	src, dst string
-	info     fs.FileInfo
-	hardlink bool
-	verbose  bool
+	src, dst     string
+	srcInfo      fs.FileInfo
+	hardlink     bool
+	verbose      bool
+	preserveMTime bool
 }
 
-func NewCopyOpts(src string, dst string, info fs.FileInfo, hardlink bool, verbose bool) CopyOpts {
-	return CopyOpts{src: src, dst: dst, info: info, hardlink: hardlink, verbose: verbose}
+func NewCopyOpts(src string, dst string, srcInfo fs.FileInfo, hardlink bool, verbose bool, preserveMTime bool) CopyOpts {
+	return CopyOpts{src: src, dst: dst, srcInfo: srcInfo, hardlink: hardlink, verbose: verbose, preserveMTime: preserveMTime}
 }

tools/copy_directory/main.go

@@ -16,6 +16,7 @@ type pathSet map[string]bool
 var srcPaths = pathSet{}
 var hardlink = false
 var verbose = false
+var preserveMTime = false
 
 type walker struct {
 	queue chan<- common.CopyOpts
@@ -68,13 +69,13 @@ func (w *walker) copyDir(src string, dst string) error {
 				return w.copyDir(linkPath, d)
 			} else {
 				// symlink points to a regular file
-				w.queue <- common.NewCopyOpts(linkPath, d, stat, hardlink, verbose)
+				w.queue <- common.NewCopyOpts(linkPath, d, stat, hardlink, verbose, preserveMTime)
 				return nil
 			}
 		}
 
 		// a regular file
-		w.queue <- common.NewCopyOpts(p, d, info, hardlink, verbose)
+		w.queue <- common.NewCopyOpts(p, d, info, hardlink, verbose, preserveMTime)
 		return nil
 	})
 }
@@ -83,7 +84,7 @@ func main() {
 	args := os.Args[1:]
 
 	if len(args) < 2 {
-		fmt.Println("Usage: copy_directory src dst [--hardlink] [--verbose]")
+		fmt.Println("Usage: copy_directory src dst [--hardlink] [--verbose] [--preserve-mtime]")
 		os.Exit(1)
 	}
 
@@ -96,6 +97,8 @@ func main() {
 				hardlink = true
 			} else if a == "--verbose" {
 				verbose = true
+			} else if a == "--preserve-mtime" {
+				preserveMTime = true
 			}
 		}
 	}

tools/copy_to_directory/main.go

@@ -40,6 +40,7 @@ type config struct {
 	IncludeSrcsPatterns         []string          `json:"include_srcs_patterns"`
 	ReplacePrefixes             map[string]string `json:"replace_prefixes"`
 	RootPaths                   []string          `json:"root_paths"`
+	PreserveMTime               bool              `json:"preserve_mtime"`
 	Verbose                     bool              `json:"verbose"`
 
 	ReplacePrefixesKeys []string
@@ -317,7 +318,7 @@ func (w *walker) copyPath(cfg *config, file fileInfo, outputPath string) error {
 
 	if !cfg.AllowOverwrites {
 		// if we don't allow overwrites then we can start copying as soon as a copy is calculated
-		w.queue <- common.NewCopyOpts(file.Path, outputPath, file.FileInfo, file.Hardlink, cfg.Verbose)
+		w.queue <- common.NewCopyOpts(file.Path, outputPath, file.FileInfo, file.Hardlink, cfg.Verbose, cfg.PreserveMTime)
 	}
 
 	return nil
@@ -419,7 +420,7 @@ func main() {
 		// if we allow overwrites then we must wait until all copy paths are calculated before starting
 		// any copy operations
 		for outputPath, file := range copySet {
-			queue <- common.NewCopyOpts(file.Path, outputPath, file.FileInfo, file.Hardlink, cfg.Verbose)
+			queue <- common.NewCopyOpts(file.Path, outputPath, file.FileInfo, file.Hardlink, cfg.Verbose, cfg.PreserveMTime)
 		}
 	}