feat: Add update command

Author: liamg

internal/cmds/update.go

@@ -0,0 +1,18 @@
+package cmds
+
+import (
+	"github.com/infracost/cli/internal/config"
+	"github.com/infracost/cli/internal/update"
+	"github.com/spf13/cobra"
+)
+
+func Update(config *config.Config) *cobra.Command {
+	return &cobra.Command{
+		Use:   "update",
+		Short: "Update to the latest version",
+		Args:  cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			return update.Update(cmd.Context())
+		},
+	}
+}

internal/cmds/version.go

@@ -0,0 +1,21 @@
+package cmds
+
+import (
+	"fmt"
+
+	"github.com/infracost/cli/internal/config"
+	"github.com/infracost/cli/version"
+	"github.com/spf13/cobra"
+)
+
+func Version(config *config.Config) *cobra.Command {
+	return &cobra.Command{
+		Use:   "version",
+		Short: "Show the current version",
+		Args:  cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			fmt.Println(version.Version)
+			return nil
+		},
+	}
+}

internal/update/update.go

@@ -0,0 +1,234 @@
+package update
+
+import (
+	"archive/tar"
+	"archive/zip"
+	"bytes"
+	"compress/gzip"
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"time"
+
+	"github.com/Masterminds/semver/v3"
+	"github.com/google/go-github/v83/github"
+	"github.com/infracost/cli/version"
+)
+
+const (
+	repoOwner = "infracost"
+	repoName  = "cli"
+)
+
+func Update(ctx context.Context) error {
+
+	currentVersion, _ := semver.NewVersion(version.Version)
+
+	client := newGitHubClient()
+
+	release, _, err := client.Repositories.GetLatestRelease(ctx, repoOwner, repoName)
+	if err != nil {
+		return fmt.Errorf("failed to fetch latest release: %w", err)
+	}
+
+	tag := release.GetTagName()
+	latestVersion, err := semver.NewVersion(tag)
+	if err != nil {
+		return fmt.Errorf("cannot parse release version %q: %w", tag, err)
+	}
+
+	if currentVersion != nil && !latestVersion.GreaterThan(currentVersion) {
+		fmt.Printf("Already up to date (v%s).\n", currentVersion)
+		return nil
+	}
+
+	fmt.Printf("Updating %s → v%s...\n", version.Version, latestVersion)
+
+	assetName := expectedAssetName(latestVersion.String())
+	var assetID int64
+	for _, a := range release.Assets {
+		if a.GetName() == assetName {
+			assetID = a.GetID()
+			break
+		}
+	}
+	if assetID == 0 {
+		return fmt.Errorf("no release asset found for %s/%s (expected %s)", runtime.GOOS, runtime.GOARCH, assetName)
+	}
+
+	rc, _, err := client.Repositories.DownloadReleaseAsset(ctx, repoOwner, repoName, assetID, &http.Client{Timeout: 60 * time.Second})
+	if err != nil {
+		return fmt.Errorf("failed to download asset: %w", err)
+	}
+	assetData, err := io.ReadAll(rc)
+	_ = rc.Close()
+	if err != nil {
+		return fmt.Errorf("failed to read asset: %w", err)
+	}
+
+	for _, binaryName := range getBinaryNames() {
+
+		binaryData, err := extractBinary(assetName, assetData, binaryName)
+		if err != nil {
+			continue
+		}
+
+		if err := replaceBinary(binaryData); err != nil {
+			return fmt.Errorf("failed to replace binary: %w", err)
+		}
+
+		fmt.Printf("Updated to v%s.\n", latestVersion)
+		return nil
+	}
+
+	return fmt.Errorf("no suitable binary found in asset %q", assetName)
+}
+
+func getBinaryNames() []string {
+	candidates := []string{"infracost-preview", "infracost"}
+	output := make([]string, 0, len(candidates))
+	for _, candidate := range candidates {
+		if runtime.GOOS == "windows" {
+			candidate += ".exe"
+		}
+		output = append(output, candidate)
+	}
+	return output
+}
+
+func newGitHubClient() *github.Client {
+	token, err := findGitHubToken()
+	if err == nil && token != "" {
+		return github.NewClient(nil).WithAuthToken(token)
+	}
+	return github.NewClient(nil)
+}
+
+func expectedAssetName(ver string) string {
+	ext := "tar.gz"
+	if runtime.GOOS == "windows" {
+		ext = "zip"
+	}
+	return fmt.Sprintf("infracost-preview_%s_%s_%s.%s", ver, runtime.GOOS, runtime.GOARCH, ext)
+}
+
+func extractBinary(assetName string, data []byte, binaryName string) ([]byte, error) {
+	if strings.HasSuffix(assetName, ".zip") {
+		return extractFromZip(data, binaryName)
+	}
+	return extractFromTarGz(data, binaryName)
+}
+
+func extractFromTarGz(data []byte, binaryName string) ([]byte, error) {
+	gz, err := gzip.NewReader(bytes.NewReader(data))
+	if err != nil {
+		return nil, err
+	}
+	defer gz.Close()
+
+	tr := tar.NewReader(gz)
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return nil, err
+		}
+		if filepath.Base(hdr.Name) == binaryName {
+			return io.ReadAll(tr)
+		}
+	}
+	return nil, fmt.Errorf("binary %q not found in archive", binaryName)
+}
+
+func extractFromZip(data []byte, binaryName string) ([]byte, error) {
+	r, err := zip.NewReader(bytes.NewReader(data), int64(len(data)))
+	if err != nil {
+		return nil, err
+	}
+	for _, f := range r.File {
+		if filepath.Base(f.Name) == binaryName {
+			rc, err := f.Open()
+			if err != nil {
+				return nil, err
+			}
+			defer rc.Close()
+			return io.ReadAll(rc)
+		}
+	}
+	return nil, fmt.Errorf("binary %q not found in archive", binaryName)
+}
+
+func replaceBinary(newBinary []byte) error {
+	execPath, err := os.Executable()
+	if err != nil {
+		return err
+	}
+	execPath, err = filepath.EvalSymlinks(execPath)
+	if err != nil {
+		return err
+	}
+
+	// Write new binary to a temp file in the same directory (ensures same filesystem for rename).
+	dir := filepath.Dir(execPath)
+	tmp, err := os.CreateTemp(dir, ".infracost-preview-update-*")
+	if err != nil {
+		return err
+	}
+	tmpPath := tmp.Name()
+
+	if _, err := tmp.Write(newBinary); err != nil {
+		tmp.Close()
+		os.Remove(tmpPath)
+		return err
+	}
+	if err := tmp.Close(); err != nil {
+		os.Remove(tmpPath)
+		return err
+	}
+
+	if err := os.Chmod(tmpPath, 0o755); err != nil {
+		os.Remove(tmpPath)
+		return err
+	}
+
+	// Atomic rename.
+	if err := os.Rename(tmpPath, execPath); err != nil {
+		os.Remove(tmpPath)
+		return err
+	}
+
+	return nil
+}
+
+var ErrTokenNotFound = fmt.Errorf("github token not found")
+
+func findGitHubToken() (string, error) {
+	if tok := os.Getenv("GH_TOKEN"); tok != "" {
+		return tok, nil
+	}
+
+	if tok := os.Getenv("GITHUB_TOKEN"); tok != "" {
+		return tok, nil
+	}
+
+	cmd := exec.Command("gh", "auth", "token")
+	cmd.Stderr = io.Discard
+	output, err := cmd.Output()
+	if err != nil {
+		return "", err
+	}
+	token := strings.TrimSpace(string(output))
+	if token != "" {
+		return token, nil
+	}
+
+	return "", ErrTokenNotFound
+}

main.go

@@ -63,6 +63,8 @@ func run() (exitCode int) {
 	cmd.AddCommand(cmds.Login(cfg))
 	cmd.AddCommand(cmds.Logout(cfg))
 	cmd.AddCommand(cmds.Price(cfg))
+	cmd.AddCommand(cmds.Update(cfg))
+	cmd.AddCommand(cmds.Version(cfg))
 
 	diags.Merge(process.PreProcess(cfg, cmd.PersistentFlags()))
 	if diags.Critical().Len() > 0 {