Send log messages to stderr, not stdout (#339)

* Move various logging messages from stdout to stderr

* Move more logging messages to stderr

* Print list of packages & their features when showing repos

* Print list of packages, deployments, and import features in summary of required pallet

* Bump version in `CHANGELOG.md`

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 0.8.0-alpha.5 - 2024-12-08
+
+### Changed
+
+- (Breaking change; cli) Log messages are now (supposed to be) printed to stderr instead of stdout; stdout is only meant to be used for outputting values meant to be piped or captured in a subshell.
+
 ## 0.8.0-alpha.4 - 2024-12-07
 
 ### Added

cmd/forklift/cache/cache.go

@@ -3,6 +3,7 @@ package cache
 import (
 	"context"
 	"fmt"
+	"os"
 	"sort"
 
 	units "github.com/docker/go-units"
@@ -21,7 +22,7 @@ var errMissingCache = errors.New(
 func getMirrorCache(wpath string, ensureWorkspace bool) (*forklift.FSMirrorCache, error) {
 	if ensureWorkspace {
 		if !forklift.DirExists(wpath) {
-			fmt.Printf("Making a new workspace at %s...", wpath)
+			fmt.Fprintf(os.Stderr, "Making a new workspace at %s...", wpath)
 		}
 		if err := forklift.EnsureExists(wpath); err != nil {
 			return nil, errors.Wrapf(err, "couldn't make new workspace at %s", wpath)
@@ -41,7 +42,7 @@ func getMirrorCache(wpath string, ensureWorkspace bool) (*forklift.FSMirrorCache
 func getPalletCache(wpath string, ensureWorkspace bool) (*forklift.FSPalletCache, error) {
 	if ensureWorkspace {
 		if !forklift.DirExists(wpath) {
-			fmt.Printf("Making a new workspace at %s...", wpath)
+			fmt.Fprintf(os.Stderr, "Making a new workspace at %s...", wpath)
 		}
 		if err := forklift.EnsureExists(wpath); err != nil {
 			return nil, errors.Wrapf(err, "couldn't make new workspace at %s", wpath)
@@ -61,7 +62,7 @@ func getPalletCache(wpath string, ensureWorkspace bool) (*forklift.FSPalletCache
 func getRepoCache(wpath string, ensureWorkspace bool) (*forklift.FSRepoCache, error) {
 	if ensureWorkspace {
 		if !forklift.DirExists(wpath) {
-			fmt.Printf("Making a new workspace at %s...", wpath)
+			fmt.Fprintf(os.Stderr, "Making a new workspace at %s...", wpath)
 		}
 		if err := forklift.EnsureExists(wpath); err != nil {
 			return nil, errors.Wrapf(err, "couldn't make new workspace at %s", wpath)
@@ -100,7 +101,7 @@ func rmAllAction(c *cli.Context) error {
 // rm-img
 
 func rmImgAction(_ *cli.Context) error {
-	fmt.Println("Removing unused Docker container images...")
+	fmt.Fprintln(os.Stderr, "Removing unused Docker container images...")
 	client, err := docker.NewClient()
 	if err != nil {
 		return errors.Wrap(err, "couldn't make Docker API client")
@@ -114,12 +115,14 @@ func rmImgAction(_ *cli.Context) error {
 	})
 	for _, deleted := range report.ImagesDeleted {
 		if deleted.Untagged != "" {
-			fmt.Printf("Untagged %s\n", deleted.Untagged)
+			fmt.Fprintf(os.Stderr, "Untagged %s\n", deleted.Untagged)
 		}
 		if deleted.Deleted != "" {
-			fmt.Printf("Deleted %s\n", deleted.Deleted)
+			fmt.Fprintf(os.Stderr, "Deleted %s\n", deleted.Deleted)
 		}
 	}
-	fmt.Printf("Total reclaimed space: %s\n", units.HumanSize(float64(report.SpaceReclaimed)))
+	fmt.Fprintf(
+		os.Stderr, "Total reclaimed space: %s\n", units.HumanSize(float64(report.SpaceReclaimed)),
+	)
 	return nil
 }

cmd/forklift/cache/downloads.go

@@ -3,6 +3,7 @@ package cache
 import (
 	"fmt"
 	"io/fs"
+	"os"
 
 	"github.com/bmatcuk/doublestar/v4"
 	"github.com/pkg/errors"
@@ -56,7 +57,7 @@ func rmDlAction(c *cli.Context) error {
 		return err
 	}
 
-	fmt.Println("Clearing downloads cache...")
+	fmt.Fprintln(os.Stderr, "Clearing downloads cache...")
 	if err = cache.Remove(); err != nil {
 		return errors.Wrap(err, "couldn't clear downloads cache")
 	}

cmd/forklift/cache/git-repositories.go

@@ -2,6 +2,8 @@ package cache
 
 import (
 	"fmt"
+	"io"
+	"os"
 	"sort"
 	"strings"
 
@@ -40,9 +42,12 @@ func lsGitRepo[GitRepo versionQuerier](
 // show-*
 
 func showGitRepo[GitRepo any](
+	out io.Writer,
 	cache core.Pather, versionQuery string,
 	loader func(path, version string) (GitRepo, error),
-	printer func(indent int, cache core.Pather, gitRepo GitRepo, printHeader bool) error,
+	fprinter func(
+		indent int, out io.Writer, cache core.Pather, gitRepo GitRepo, printHeader bool,
+	) error,
 	printHeader bool,
 ) error {
 	gitRepoPath, version, ok := strings.Cut(versionQuery, "@")
@@ -55,7 +60,7 @@ func showGitRepo[GitRepo any](
 	if err != nil {
 		return errors.Wrapf(err, "couldn't find %s@%s", gitRepoPath, version)
 	}
-	return printer(0, cache, gitRepo, printHeader)
+	return fprinter(0, out, cache, gitRepo, printHeader)
 }
 
 // add-*
@@ -79,8 +84,8 @@ func addGitRepoAction[Cache core.Pather](
 		); err != nil {
 			return err
 		}
-		fmt.Println()
-		fmt.Println("Done!")
+		fmt.Fprintln(os.Stderr)
+		fmt.Fprintln(os.Stderr, "Done!")
 		return nil
 	}
 }
@@ -100,7 +105,7 @@ func rmGitRepoAction[Cache remover](
 			return err
 		}
 
-		fmt.Printf("Clearing %s cache...\n", gitRepoType)
+		fmt.Fprintf(os.Stderr, "Clearing %s cache...\n", gitRepoType)
 		if err = cache.Remove(); err != nil {
 			return errors.Wrapf(err, "couldn't clear %s cache", gitRepoType)
 		}

cmd/forklift/cache/packages.go

@@ -2,6 +2,7 @@ package cache
 
 import (
 	"fmt"
+	"os"
 	"sort"
 	"strings"
 
@@ -59,6 +60,6 @@ func showPkgAction(c *cli.Context) error {
 	if err != nil {
 		return errors.Wrapf(err, "couldn't resolve package query %s@%s", pkgPath, version)
 	}
-	fcli.PrintPkg(0, cache, pkg)
+	fcli.FprintPkg(0, os.Stdout, cache, pkg)
 	return nil
 }

cmd/forklift/cache/pallets.go

@@ -1,6 +1,8 @@
 package cache
 
 import (
+	"os"
+
 	"github.com/urfave/cli/v2"
 
 	"github.com/PlanktoScope/forklift/internal/app/forklift"
@@ -35,5 +37,7 @@ func showPltAction(c *cli.Context) error {
 		return errMissingCache
 	}
 
-	return showGitRepo(cache, c.Args().First(), cache.LoadFSPallet, fcli.PrintCachedPallet, true)
+	return showGitRepo(
+		os.Stdout, cache, c.Args().First(), cache.LoadFSPallet, fcli.FprintCachedPallet, true,
+	)
 }

cmd/forklift/cache/repositories.go

@@ -1,6 +1,8 @@
 package cache
 
 import (
+	"os"
+
 	"github.com/urfave/cli/v2"
 
 	fcli "github.com/PlanktoScope/forklift/internal/app/forklift/cli"
@@ -35,5 +37,7 @@ func showRepoAction(c *cli.Context) error {
 		return errMissingCache
 	}
 
-	return showGitRepo(cache, c.Args().First(), cache.LoadFSRepo, fcli.PrintCachedRepo, true)
+	return showGitRepo(
+		os.Stdout, cache, c.Args().First(), cache.LoadFSRepo, fcli.FprintCachedRepo, true,
+	)
 }

cmd/forklift/dev/plt/deployments.go

@@ -2,6 +2,7 @@ package plt
 
 import (
 	"fmt"
+	"os"
 
 	"github.com/urfave/cli/v2"
 
@@ -19,7 +20,7 @@ func lsDeplAction(c *cli.Context) error {
 		return err
 	}
 
-	return fcli.PrintPalletDepls(0, plt)
+	return fcli.FprintPalletDepls(0, os.Stdout, plt)
 }
 
 // show-depl
@@ -34,7 +35,7 @@ func showDeplAction(c *cli.Context) error {
 		return err
 	}
 
-	return fcli.PrintDeplInfo(0, plt, caches.r, c.Args().First())
+	return fcli.FprintDeplInfo(0, os.Stdout, plt, caches.r, c.Args().First())
 }
 
 // locate-depl-pkg
@@ -49,7 +50,9 @@ func locateDeplPkgAction(c *cli.Context) error {
 		return err
 	}
 
-	return fcli.PrintDeplPkgLocation(0, plt, caches.r, c.Args().First(), c.Bool("allow-disabled"))
+	return fcli.FprintDeplPkgLocation(
+		0, os.Stdout, plt, caches.r, c.Args().First(), c.Bool("allow-disabled"),
+	)
 }
 
 // add-depl
@@ -86,7 +89,7 @@ func addDeplAction(versions Versions) cli.ActionFunc {
 		case c.Bool("stage"):
 			return stageAction(versions)(c)
 		default:
-			fmt.Println("Done!")
+			fmt.Fprintln(os.Stderr, "Done!")
 			return nil
 		}
 	}
@@ -121,7 +124,7 @@ func rmDeplAction(versions Versions) cli.ActionFunc {
 		case c.Bool("stage"):
 			return stageAction(versions)(c)
 		default:
-			fmt.Println("Done!")
+			fmt.Fprintln(os.Stderr, "Done!")
 			return nil
 		}
 	}
@@ -158,7 +161,7 @@ func setDeplPkgAction(versions Versions) cli.ActionFunc {
 		case c.Bool("stage"):
 			return stageAction(versions)(c)
 		default:
-			fmt.Println("Done!")
+			fmt.Fprintln(os.Stderr, "Done!")
 			return nil
 		}
 	}
@@ -197,7 +200,7 @@ func addDeplFeatAction(versions Versions) cli.ActionFunc {
 		case c.Bool("stage"):
 			return stageAction(versions)(c)
 		default:
-			fmt.Println("Done!")
+			fmt.Fprintln(os.Stderr, "Done!")
 			return nil
 		}
 	}
@@ -234,7 +237,7 @@ func rmDeplFeatAction(versions Versions) cli.ActionFunc {
 		case c.Bool("stage"):
 			return stageAction(versions)(c)
 		default:
-			fmt.Println("Done!")
+			fmt.Fprintln(os.Stderr, "Done!")
 			return nil
 		}
 	}
@@ -270,7 +273,7 @@ func setDeplDisabledAction(versions Versions, setting bool) cli.ActionFunc {
 		case c.Bool("stage"):
 			return stageAction(versions)(c)
 		default:
-			fmt.Println("Done!")
+			fmt.Fprintln(os.Stderr, "Done!")
 			return nil
 		}
 	}

cmd/forklift/dev/plt/downloads.go

@@ -2,6 +2,7 @@ package plt
 
 import (
 	"fmt"
+	"os"
 
 	"github.com/urfave/cli/v2"
 
@@ -57,8 +58,8 @@ func cacheDlAction(versions Versions) cli.ActionFunc {
 		); err != nil {
 			return err
 		}
-		fmt.Println()
-		fmt.Println("Done!")
+		fmt.Fprintln(os.Stderr)
+		fmt.Fprintln(os.Stderr, "Done!")
 		return nil
 	}
 }

cmd/forklift/dev/plt/features.go

@@ -1,6 +1,8 @@
 package plt
 
 import (
+	"os"
+
 	"github.com/urfave/cli/v2"
 
 	fcli "github.com/PlanktoScope/forklift/internal/app/forklift/cli"
@@ -18,7 +20,7 @@ func lsFeatAction(c *cli.Context) error {
 		return err
 	}
 
-	return fcli.PrintPalletFeatures(0, plt)
+	return fcli.FprintPalletFeatures(0, os.Stdout, plt)
 }
 
 // show-feat
@@ -33,5 +35,5 @@ func showFeatAction(c *cli.Context) error {
 		return err
 	}
 
-	return fcli.PrintFeatureInfo(0, plt, caches.p, c.Args().First())
+	return fcli.FprintFeatureInfo(0, os.Stdout, plt, caches.p, c.Args().First())
 }

cmd/forklift/dev/plt/files.go

@@ -2,6 +2,7 @@ package plt
 
 import (
 	"fmt"
+	"os"
 
 	"github.com/urfave/cli/v2"
 
@@ -64,7 +65,7 @@ func showFileAction(c *cli.Context) error {
 		return err
 	}
 
-	return fcli.PrintFile(plt, c.Args().First())
+	return fcli.FprintFile(os.Stdout, plt, c.Args().First())
 }
 
 // edit-file

cmd/forklift/dev/plt/images.go

@@ -2,6 +2,7 @@ package plt
 
 import (
 	"fmt"
+	"os"
 
 	"github.com/urfave/cli/v2"
 
@@ -49,14 +50,16 @@ func cacheImgAction(versions Versions) cli.ActionFunc {
 			return err
 		}
 
-		fmt.Println("Downloading Docker container images specified by the development pallet...")
+		fmt.Fprintln(
+			os.Stderr, "Downloading Docker container images specified by the development pallet...",
+		)
 		if err := fcli.DownloadImages(
 			0, plt, caches.r, c.String("platform"), c.Bool("include-disabled"), c.Bool("parallel"),
 		); err != nil {
 			return err
 		}
-		fmt.Println()
-		fmt.Println("Done!")
+		fmt.Fprintln(os.Stderr)
+		fmt.Fprintln(os.Stderr, "Done!")
 		return nil
 	}
 }