feat(apt,dpkg): implement apt and dpkg package manager wrappers

Implement the snack.Manager interface for both apt (Debian/Ubuntu) and dpkg (low-level Debian package tool). apt wraps apt-get, apt-cache, and dpkg-query for full package management. dpkg wraps dpkg and dpkg-query for low-level .deb operations. Upgrade and Update return ErrUnsupportedPlatform for dpkg. Both packages include: - Linux implementations with proper error wrapping - Non-linux build stubs returning ErrUnsupportedPlatform - Output parsing helpers with tests - Functional options support (sudo, assume-yes, dry-run)
2026-04-02 05:08:42 -07:00 · 2026-02-25 20:25:19 +00:00
parent f04365e600
commit 5163a948ea
10 changed files with 838 additions and 0 deletions
--- a/apt/apt.go
+++ b/apt/apt.go
@@ -1,2 +1,74 @@
 // Package apt provides Go bindings for APT (Advanced Packaging Tool) on Debian/Ubuntu.
 package apt
+
+import (
+	"context"
+
+	"github.com/gogrlx/snack"
+)
+
+// Apt implements the snack.Manager interface using apt-get and apt-cache.
+type Apt struct{}
+
+// New returns a new Apt manager.
+func New() *Apt {
+	return &Apt{}
+}
+
+// Name returns "apt".
+func (a *Apt) Name() string { return "apt" }
+
+// Install one or more packages.
+func (a *Apt) Install(ctx context.Context, pkgs []string, opts ...snack.Option) error {
+	return install(ctx, pkgs, opts...)
+}
+
+// Remove one or more packages.
+func (a *Apt) Remove(ctx context.Context, pkgs []string, opts ...snack.Option) error {
+	return remove(ctx, pkgs, opts...)
+}
+
+// Purge one or more packages including config files.
+func (a *Apt) Purge(ctx context.Context, pkgs []string, opts ...snack.Option) error {
+	return purge(ctx, pkgs, opts...)
+}
+
+// Upgrade all installed packages.
+func (a *Apt) Upgrade(ctx context.Context, opts ...snack.Option) error {
+	return upgrade(ctx, opts...)
+}
+
+// Update refreshes the package index.
+func (a *Apt) Update(ctx context.Context) error {
+	return update(ctx)
+}
+
+// List returns all installed packages.
+func (a *Apt) List(ctx context.Context) ([]snack.Package, error) {
+	return list(ctx)
+}
+
+// Search queries the package index.
+func (a *Apt) Search(ctx context.Context, query string) ([]snack.Package, error) {
+	return search(ctx, query)
+}
+
+// Info returns details about a specific package.
+func (a *Apt) Info(ctx context.Context, pkg string) (*snack.Package, error) {
+	return info(ctx, pkg)
+}
+
+// IsInstalled reports whether a package is currently installed.
+func (a *Apt) IsInstalled(ctx context.Context, pkg string) (bool, error) {
+	return isInstalled(ctx, pkg)
+}
+
+// Version returns the installed version of a package.
+func (a *Apt) Version(ctx context.Context, pkg string) (string, error) {
+	return version(ctx, pkg)
+}
+
+// Available reports whether apt-get is present on the system.
+func (a *Apt) Available() bool {
+	return available()
+}
--- a/apt/apt_linux.go
+++ b/apt/apt_linux.go
@@ -0,0 +1,138 @@
+//go:build linux
+
+package apt
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os/exec"
+	"strings"
+
+	"github.com/gogrlx/snack"
+)
+
+func available() bool {
+	_, err := exec.LookPath("apt-get")
+	return err == nil
+}
+
+func buildArgs(command string, pkgs []string, opts ...snack.Option) []string {
+	o := snack.ApplyOptions(opts...)
+	var args []string
+	if o.Sudo {
+		args = append(args, "sudo")
+	}
+	args = append(args, "apt-get", command)
+	if o.AssumeYes {
+		args = append(args, "-y")
+	}
+	if o.DryRun {
+		args = append(args, "--dry-run")
+	}
+	args = append(args, pkgs...)
+	return args
+}
+
+func runAptGet(ctx context.Context, command string, pkgs []string, opts ...snack.Option) error {
+	args := buildArgs(command, pkgs, opts...)
+	var cmd *exec.Cmd
+	if args[0] == "sudo" {
+		cmd = exec.CommandContext(ctx, args[0], args[1:]...)
+	} else {
+		cmd = exec.CommandContext(ctx, args[0], args[1:]...)
+	}
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	if err := cmd.Run(); err != nil {
+		errMsg := stderr.String()
+		if strings.Contains(errMsg, "Permission denied") || strings.Contains(errMsg, "are you root") {
+			return fmt.Errorf("apt-get %s: %w", command, snack.ErrPermissionDenied)
+		}
+		if strings.Contains(errMsg, "Unable to locate package") {
+			return fmt.Errorf("apt-get %s: %w", command, snack.ErrNotFound)
+		}
+		return fmt.Errorf("apt-get %s: %w: %s", command, err, errMsg)
+	}
+	return nil
+}
+
+func install(ctx context.Context, pkgs []string, opts ...snack.Option) error {
+	return runAptGet(ctx, "install", pkgs, opts...)
+}
+
+func remove(ctx context.Context, pkgs []string, opts ...snack.Option) error {
+	return runAptGet(ctx, "remove", pkgs, opts...)
+}
+
+func purge(ctx context.Context, pkgs []string, opts ...snack.Option) error {
+	return runAptGet(ctx, "purge", pkgs, opts...)
+}
+
+func upgrade(ctx context.Context, opts ...snack.Option) error {
+	return runAptGet(ctx, "upgrade", nil, opts...)
+}
+
+func update(ctx context.Context) error {
+	cmd := exec.CommandContext(ctx, "apt-get", "update")
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("apt-get update: %w: %s", err, stderr.String())
+	}
+	return nil
+}
+
+func list(ctx context.Context) ([]snack.Package, error) {
+	cmd := exec.CommandContext(ctx, "dpkg-query", "-W", "-f=${Package}\\t${Version}\\t${Description}\\n")
+	out, err := cmd.Output()
+	if err != nil {
+		return nil, fmt.Errorf("dpkg-query list: %w", err)
+	}
+	return parseList(string(out)), nil
+}
+
+func search(ctx context.Context, query string) ([]snack.Package, error) {
+	cmd := exec.CommandContext(ctx, "apt-cache", "search", query)
+	out, err := cmd.Output()
+	if err != nil {
+		return nil, fmt.Errorf("apt-cache search: %w", err)
+	}
+	return parseSearch(string(out)), nil
+}
+
+func info(ctx context.Context, pkg string) (*snack.Package, error) {
+	cmd := exec.CommandContext(ctx, "apt-cache", "show", pkg)
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	out, err := cmd.Output()
+	if err != nil {
+		if strings.Contains(stderr.String(), "No packages found") {
+			return nil, fmt.Errorf("apt-cache show %s: %w", pkg, snack.ErrNotFound)
+		}
+		return nil, fmt.Errorf("apt-cache show %s: %w", pkg, err)
+	}
+	return parseInfo(string(out))
+}
+
+func isInstalled(ctx context.Context, pkg string) (bool, error) {
+	cmd := exec.CommandContext(ctx, "dpkg-query", "-W", "-f=${Status}", pkg)
+	out, err := cmd.Output()
+	if err != nil {
+		return false, nil
+	}
+	return strings.TrimSpace(string(out)) == "install ok installed", nil
+}
+
+func version(ctx context.Context, pkg string) (string, error) {
+	cmd := exec.CommandContext(ctx, "dpkg-query", "-W", "-f=${Version}", pkg)
+	out, err := cmd.Output()
+	if err != nil {
+		return "", fmt.Errorf("version %s: %w", pkg, snack.ErrNotInstalled)
+	}
+	v := strings.TrimSpace(string(out))
+	if v == "" {
+		return "", fmt.Errorf("version %s: %w", pkg, snack.ErrNotInstalled)
+	}
+	return v, nil
+}
--- a/apt/apt_other.go
+++ b/apt/apt_other.go
@@ -0,0 +1,51 @@
+//go:build !linux
+
+package apt
+
+import (
+	"context"
+
+	"github.com/gogrlx/snack"
+)
+
+func available() bool { return false }
+
+func install(_ context.Context, _ []string, _ ...snack.Option) error {
+	return snack.ErrUnsupportedPlatform
+}
+
+func remove(_ context.Context, _ []string, _ ...snack.Option) error {
+	return snack.ErrUnsupportedPlatform
+}
+
+func purge(_ context.Context, _ []string, _ ...snack.Option) error {
+	return snack.ErrUnsupportedPlatform
+}
+
+func upgrade(_ context.Context, _ ...snack.Option) error {
+	return snack.ErrUnsupportedPlatform
+}
+
+func update(_ context.Context) error {
+	return snack.ErrUnsupportedPlatform
+}
+
+func list(_ context.Context) ([]snack.Package, error) {
+	return nil, snack.ErrUnsupportedPlatform
+}
+
+func search(_ context.Context, _ string) ([]snack.Package, error) {
+	return nil, snack.ErrUnsupportedPlatform
+}
+
+func info(_ context.Context, _ string) (*snack.Package, error) {
+	return nil, snack.ErrUnsupportedPlatform
+}
+
+func isInstalled(_ context.Context, _ string) (bool, error) {
+	return false, snack.ErrUnsupportedPlatform
+}
+
+func version(_ context.Context, _ string) (string, error) {
+	return "", snack.ErrUnsupportedPlatform
+}
--- a/apt/apt_test.go
+++ b/apt/apt_test.go
@@ -0,0 +1,71 @@
+package apt
+
+import (
+	"testing"
+
+	"github.com/gogrlx/snack"
+)
+
+func TestParseList(t *testing.T) {
+	input := "bash\t5.2-1\tGNU Bourne Again SHell\ncoreutils\t9.1-1\tGNU core utilities\n"
+	pkgs := parseList(input)
+	if len(pkgs) != 2 {
+		t.Fatalf("expected 2 packages, got %d", len(pkgs))
+	}
+	if pkgs[0].Name != "bash" || pkgs[0].Version != "5.2-1" {
+		t.Errorf("unexpected first package: %+v", pkgs[0])
+	}
+	if !pkgs[0].Installed {
+		t.Error("expected Installed=true")
+	}
+}
+
+func TestParseSearch(t *testing.T) {
+	input := "vim - Vi IMproved\nnano - small text editor\n"
+	pkgs := parseSearch(input)
+	if len(pkgs) != 2 {
+		t.Fatalf("expected 2 packages, got %d", len(pkgs))
+	}
+	if pkgs[0].Name != "vim" || pkgs[0].Description != "Vi IMproved" {
+		t.Errorf("unexpected package: %+v", pkgs[0])
+	}
+}
+
+func TestParseInfo(t *testing.T) {
+	input := `Package: bash
+Version: 5.2-1
+Architecture: amd64
+Description: GNU Bourne Again SHell
+`
+	p, err := parseInfo(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if p.Name != "bash" || p.Version != "5.2-1" || p.Arch != "amd64" {
+		t.Errorf("unexpected package: %+v", p)
+	}
+}
+
+func TestParseInfoEmpty(t *testing.T) {
+	_, err := parseInfo("")
+	if err != snack.ErrNotFound {
+		t.Errorf("expected ErrNotFound, got %v", err)
+	}
+}
+
+func TestParseListEmpty(t *testing.T) {
+	pkgs := parseList("")
+	if len(pkgs) != 0 {
+		t.Errorf("expected 0 packages, got %d", len(pkgs))
+	}
+}
+
+func TestNew(t *testing.T) {
+	a := New()
+	if a.Name() != "apt" {
+		t.Errorf("expected 'apt', got %q", a.Name())
+	}
+}
+
+// Verify Apt implements snack.Manager at compile time.
+var _ snack.Manager = (*Apt)(nil)
--- a/apt/parse.go
+++ b/apt/parse.go
@@ -0,0 +1,77 @@
+package apt
+
+import (
+	"strings"
+
+	"github.com/gogrlx/snack"
+)
+
+// parseList parses dpkg-query -W output into packages.
+func parseList(output string) []snack.Package {
+	var pkgs []snack.Package
+	for _, line := range strings.Split(strings.TrimSpace(output), "\n") {
+		if line == "" {
+			continue
+		}
+		parts := strings.SplitN(line, "\t", 3)
+		if len(parts) < 2 {
+			continue
+		}
+		p := snack.Package{
+			Name:      parts[0],
+			Version:   parts[1],
+			Installed: true,
+		}
+		if len(parts) == 3 {
+			p.Description = parts[2]
+		}
+		pkgs = append(pkgs, p)
+	}
+	return pkgs
+}
+
+// parseSearch parses apt-cache search output.
+func parseSearch(output string) []snack.Package {
+	var pkgs []snack.Package
+	for _, line := range strings.Split(strings.TrimSpace(output), "\n") {
+		if line == "" {
+			continue
+		}
+		// Format: "package - description"
+		parts := strings.SplitN(line, " - ", 2)
+		if len(parts) < 1 {
+			continue
+		}
+		p := snack.Package{Name: strings.TrimSpace(parts[0])}
+		if len(parts) == 2 {
+			p.Description = strings.TrimSpace(parts[1])
+		}
+		pkgs = append(pkgs, p)
+	}
+	return pkgs
+}
+
+// parseInfo parses apt-cache show output into a Package.
+func parseInfo(output string) (*snack.Package, error) {
+	p := &snack.Package{}
+	for _, line := range strings.Split(output, "\n") {
+		key, val, ok := strings.Cut(line, ": ")
+		if !ok {
+			continue
+		}
+		switch key {
+		case "Package":
+			p.Name = val
+		case "Version":
+			p.Version = val
+		case "Description":
+			p.Description = val
+		case "Architecture":
+			p.Arch = val
+		}
+	}
+	if p.Name == "" {
+		return nil, snack.ErrNotFound
+	}
+	return p, nil
+}
--- a/dpkg/dpkg.go
+++ b/dpkg/dpkg.go
@@ -1,2 +1,74 @@
 // Package dpkg provides Go bindings for dpkg (low-level Debian package tool).
 package dpkg
+
+import (
+	"context"
+
+	"github.com/gogrlx/snack"
+)
+
+// Dpkg implements the snack.Manager interface using dpkg and dpkg-query.
+type Dpkg struct{}
+
+// New returns a new Dpkg manager.
+func New() *Dpkg {
+	return &Dpkg{}
+}
+
+// Name returns "dpkg".
+func (d *Dpkg) Name() string { return "dpkg" }
+
+// Install one or more .deb files.
+func (d *Dpkg) Install(ctx context.Context, pkgs []string, opts ...snack.Option) error {
+	return install(ctx, pkgs, opts...)
+}
+
+// Remove one or more packages.
+func (d *Dpkg) Remove(ctx context.Context, pkgs []string, opts ...snack.Option) error {
+	return remove(ctx, pkgs, opts...)
+}
+
+// Purge one or more packages including config files.
+func (d *Dpkg) Purge(ctx context.Context, pkgs []string, opts ...snack.Option) error {
+	return purge(ctx, pkgs, opts...)
+}
+
+// Upgrade is not supported by dpkg.
+func (d *Dpkg) Upgrade(_ context.Context, _ ...snack.Option) error {
+	return snack.ErrUnsupportedPlatform
+}
+
+// Update is not supported by dpkg.
+func (d *Dpkg) Update(_ context.Context) error {
+	return snack.ErrUnsupportedPlatform
+}
+
+// List returns all installed packages.
+func (d *Dpkg) List(ctx context.Context) ([]snack.Package, error) {
+	return list(ctx)
+}
+
+// Search queries installed packages matching the pattern.
+func (d *Dpkg) Search(ctx context.Context, query string) ([]snack.Package, error) {
+	return search(ctx, query)
+}
+
+// Info returns details about a specific package.
+func (d *Dpkg) Info(ctx context.Context, pkg string) (*snack.Package, error) {
+	return info(ctx, pkg)
+}
+
+// IsInstalled reports whether a package is currently installed.
+func (d *Dpkg) IsInstalled(ctx context.Context, pkg string) (bool, error) {
+	return isInstalled(ctx, pkg)
+}
+
+// Version returns the installed version of a package.
+func (d *Dpkg) Version(ctx context.Context, pkg string) (string, error) {
+	return version(ctx, pkg)
+}
+
+// Available reports whether dpkg is present on the system.
+func (d *Dpkg) Available() bool {
+	return available()
+}
--- a/dpkg/dpkg_linux.go
+++ b/dpkg/dpkg_linux.go
@@ -0,0 +1,138 @@
+//go:build linux
+
+package dpkg
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os/exec"
+	"strings"
+
+	"github.com/gogrlx/snack"
+)
+
+func available() bool {
+	_, err := exec.LookPath("dpkg")
+	return err == nil
+}
+
+func install(ctx context.Context, pkgs []string, opts ...snack.Option) error {
+	o := snack.ApplyOptions(opts...)
+	var args []string
+	if o.Sudo {
+		args = append(args, "sudo")
+	}
+	args = append(args, "dpkg", "-i")
+	if o.DryRun {
+		args = append(args, "--simulate")
+	}
+	args = append(args, pkgs...)
+	cmd := exec.CommandContext(ctx, args[0], args[1:]...)
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	if err := cmd.Run(); err != nil {
+		errMsg := stderr.String()
+		if strings.Contains(errMsg, "Permission denied") || strings.Contains(errMsg, "are you root") {
+			return fmt.Errorf("dpkg -i: %w", snack.ErrPermissionDenied)
+		}
+		return fmt.Errorf("dpkg -i: %w: %s", err, errMsg)
+	}
+	return nil
+}
+
+func remove(ctx context.Context, pkgs []string, opts ...snack.Option) error {
+	o := snack.ApplyOptions(opts...)
+	var args []string
+	if o.Sudo {
+		args = append(args, "sudo")
+	}
+	args = append(args, "dpkg", "-r")
+	if o.DryRun {
+		args = append(args, "--simulate")
+	}
+	args = append(args, pkgs...)
+	cmd := exec.CommandContext(ctx, args[0], args[1:]...)
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("dpkg -r: %w: %s", err, stderr.String())
+	}
+	return nil
+}
+
+func purge(ctx context.Context, pkgs []string, opts ...snack.Option) error {
+	o := snack.ApplyOptions(opts...)
+	var args []string
+	if o.Sudo {
+		args = append(args, "sudo")
+	}
+	args = append(args, "dpkg", "-P")
+	if o.DryRun {
+		args = append(args, "--simulate")
+	}
+	args = append(args, pkgs...)
+	cmd := exec.CommandContext(ctx, args[0], args[1:]...)
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("dpkg -P: %w: %s", err, stderr.String())
+	}
+	return nil
+}
+
+func list(ctx context.Context) ([]snack.Package, error) {
+	cmd := exec.CommandContext(ctx, "dpkg-query", "-W", "-f=${Package}\\t${Version}\\t${Status}\\n")
+	out, err := cmd.Output()
+	if err != nil {
+		return nil, fmt.Errorf("dpkg-query list: %w", err)
+	}
+	return parseList(string(out)), nil
+}
+
+func search(ctx context.Context, query string) ([]snack.Package, error) {
+	pattern := fmt.Sprintf("*%s*", query)
+	cmd := exec.CommandContext(ctx, "dpkg-query", "-l", pattern)
+	out, err := cmd.Output()
+	if err != nil {
+		// dpkg-query -l returns exit 1 when no packages match
+		return nil, nil
+	}
+	return parseDpkgList(string(out)), nil
+}
+
+func info(ctx context.Context, pkg string) (*snack.Package, error) {
+	cmd := exec.CommandContext(ctx, "dpkg-query", "-s", pkg)
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	out, err := cmd.Output()
+	if err != nil {
+		if strings.Contains(stderr.String(), "is not installed") || strings.Contains(stderr.String(), "not found") {
+			return nil, fmt.Errorf("dpkg-query -s %s: %w", pkg, snack.ErrNotInstalled)
+		}
+		return nil, fmt.Errorf("dpkg-query -s %s: %w", pkg, err)
+	}
+	return parseInfo(string(out))
+}
+
+func isInstalled(ctx context.Context, pkg string) (bool, error) {
+	cmd := exec.CommandContext(ctx, "dpkg-query", "-W", "-f=${Status}", pkg)
+	out, err := cmd.Output()
+	if err != nil {
+		return false, nil
+	}
+	return strings.TrimSpace(string(out)) == "install ok installed", nil
+}
+
+func version(ctx context.Context, pkg string) (string, error) {
+	cmd := exec.CommandContext(ctx, "dpkg-query", "-W", "-f=${Version}", pkg)
+	out, err := cmd.Output()
+	if err != nil {
+		return "", fmt.Errorf("version %s: %w", pkg, snack.ErrNotInstalled)
+	}
+	v := strings.TrimSpace(string(out))
+	if v == "" {
+		return "", fmt.Errorf("version %s: %w", pkg, snack.ErrNotInstalled)
+	}
+	return v, nil
+}
--- a/dpkg/dpkg_other.go
+++ b/dpkg/dpkg_other.go
@@ -0,0 +1,43 @@
+//go:build !linux
+
+package dpkg
+
+import (
+	"context"
+
+	"github.com/gogrlx/snack"
+)
+
+func available() bool { return false }
+
+func install(_ context.Context, _ []string, _ ...snack.Option) error {
+	return snack.ErrUnsupportedPlatform
+}
+
+func remove(_ context.Context, _ []string, _ ...snack.Option) error {
+	return snack.ErrUnsupportedPlatform
+}
+
+func purge(_ context.Context, _ []string, _ ...snack.Option) error {
+	return snack.ErrUnsupportedPlatform
+}
+
+func list(_ context.Context) ([]snack.Package, error) {
+	return nil, snack.ErrUnsupportedPlatform
+}
+
+func search(_ context.Context, _ string) ([]snack.Package, error) {
+	return nil, snack.ErrUnsupportedPlatform
+}
+
+func info(_ context.Context, _ string) (*snack.Package, error) {
+	return nil, snack.ErrUnsupportedPlatform
+}
+
+func isInstalled(_ context.Context, _ string) (bool, error) {
+	return false, snack.ErrUnsupportedPlatform
+}
+
+func version(_ context.Context, _ string) (string, error) {
+	return "", snack.ErrUnsupportedPlatform
+}
--- a/dpkg/dpkg_test.go
+++ b/dpkg/dpkg_test.go
@@ -0,0 +1,89 @@
+package dpkg
+
+import (
+	"testing"
+
+	"github.com/gogrlx/snack"
+)
+
+func TestParseList(t *testing.T) {
+	input := "bash\t5.2-1\tinstall ok installed\ncoreutils\t9.1-1\tdeinstall ok config-files\n"
+	pkgs := parseList(input)
+	if len(pkgs) != 2 {
+		t.Fatalf("expected 2 packages, got %d", len(pkgs))
+	}
+	if pkgs[0].Name != "bash" || !pkgs[0].Installed {
+		t.Errorf("unexpected first package: %+v", pkgs[0])
+	}
+	if pkgs[1].Installed {
+		t.Errorf("expected second package not installed: %+v", pkgs[1])
+	}
+}
+
+func TestParseDpkgList(t *testing.T) {
+	input := `Desired=Unknown/Install/Remove/Purge/Hold
+| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
+|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
+||/ Name           Version      Architecture Description
+++-==============-============-============-=================================
+ii  bash           5.2-1        amd64        GNU Bourne Again SHell
+rc  oldpkg         1.0-1        amd64        Some old package
+`
+	pkgs := parseDpkgList(input)
+	if len(pkgs) != 2 {
+		t.Fatalf("expected 2 packages, got %d", len(pkgs))
+	}
+	if pkgs[0].Name != "bash" || !pkgs[0].Installed {
+		t.Errorf("unexpected: %+v", pkgs[0])
+	}
+	if pkgs[1].Installed {
+		t.Errorf("expected oldpkg not installed: %+v", pkgs[1])
+	}
+}
+
+func TestParseInfo(t *testing.T) {
+	input := `Package: bash
+Status: install ok installed
+Version: 5.2-1
+Architecture: amd64
+Description: GNU Bourne Again SHell
+`
+	p, err := parseInfo(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if p.Name != "bash" || p.Version != "5.2-1" || !p.Installed {
+		t.Errorf("unexpected: %+v", p)
+	}
+}
+
+func TestParseInfoEmpty(t *testing.T) {
+	_, err := parseInfo("")
+	if err != snack.ErrNotFound {
+		t.Errorf("expected ErrNotFound, got %v", err)
+	}
+}
+
+func TestNew(t *testing.T) {
+	d := New()
+	if d.Name() != "dpkg" {
+		t.Errorf("expected 'dpkg', got %q", d.Name())
+	}
+}
+
+func TestUpgradeUnsupported(t *testing.T) {
+	d := New()
+	if err := d.Upgrade(nil); err != snack.ErrUnsupportedPlatform {
+		t.Errorf("expected ErrUnsupportedPlatform, got %v", err)
+	}
+}
+
+func TestUpdateUnsupported(t *testing.T) {
+	d := New()
+	if err := d.Update(nil); err != snack.ErrUnsupportedPlatform {
+		t.Errorf("expected ErrUnsupportedPlatform, got %v", err)
+	}
+}
+
+// Verify Dpkg implements snack.Manager at compile time.
+var _ snack.Manager = (*Dpkg)(nil)
--- a/dpkg/parse.go
+++ b/dpkg/parse.go
@@ -0,0 +1,87 @@
+package dpkg
+
+import (
+	"strings"
+
+	"github.com/gogrlx/snack"
+)
+
+// parseList parses dpkg-query -W -f='${Package}\t${Version}\t${Status}\n' output.
+func parseList(output string) []snack.Package {
+	var pkgs []snack.Package
+	for _, line := range strings.Split(strings.TrimSpace(output), "\n") {
+		if line == "" {
+			continue
+		}
+		parts := strings.SplitN(line, "\t", 3)
+		if len(parts) < 2 {
+			continue
+		}
+		p := snack.Package{
+			Name:    parts[0],
+			Version: parts[1],
+		}
+		if len(parts) == 3 && strings.Contains(parts[2], "install ok installed") {
+			p.Installed = true
+		}
+		pkgs = append(pkgs, p)
+	}
+	return pkgs
+}
+
+// parseDpkgList parses dpkg-query -l output (table format with header).
+func parseDpkgList(output string) []snack.Package {
+	var pkgs []snack.Package
+	for _, line := range strings.Split(output, "\n") {
+		// Data lines start with status flags like "ii", "rc", etc.
+		if len(line) < 4 || line[2] != ' ' {
+			continue
+		}
+		// Skip lines where flags aren't letters (e.g. "+++-..." separator)
+		if line[0] < 'a' || line[0] > 'z' {
+			continue
+		}
+		status := line[:2]
+		fields := strings.Fields(line[3:])
+		if len(fields) < 2 {
+			continue
+		}
+		p := snack.Package{
+			Name:      fields[0],
+			Version:   fields[1],
+			Installed: status == "ii",
+		}
+		if len(fields) > 3 {
+			p.Description = strings.Join(fields[3:], " ")
+		}
+		pkgs = append(pkgs, p)
+	}
+	return pkgs
+}
+
+// parseInfo parses dpkg-query -s output into a Package.
+func parseInfo(output string) (*snack.Package, error) {
+	p := &snack.Package{}
+	for _, line := range strings.Split(output, "\n") {
+		key, val, ok := strings.Cut(line, ": ")
+		if !ok {
+			continue
+		}
+		switch key {
+		case "Package":
+			p.Name = val
+		case "Version":
+			p.Version = val
+		case "Description":
+			p.Description = val
+		case "Architecture":
+			p.Arch = val
+		case "Status":
+			p.Installed = val == "install ok installed"
+		}
+	}
+	if p.Name == "" {
+		return nil, snack.ErrNotFound
+	}
+	return p, nil
+}