Internalize majority of cmd package (#2533)

* internalize majority of cmd package and migrate integration tests

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* add internal api encoder

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* create internal representation of all formats

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* export capability to get default encoders

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* restore test fixtures

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

---------

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

cmd/syft/internal/commands/update.go

@@ -0,0 +1,121 @@
+package commands
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+
+	"github.com/spf13/cobra"
+	"github.com/wagoodman/go-partybus"
+
+	"github.com/anchore/clio"
+	hashiVersion "github.com/anchore/go-version"
+	"github.com/anchore/syft/cmd/syft/internal"
+	"github.com/anchore/syft/cmd/syft/internal/options"
+	"github.com/anchore/syft/internal/bus"
+	"github.com/anchore/syft/internal/log"
+	"github.com/anchore/syft/syft/event"
+	"github.com/anchore/syft/syft/event/parsers"
+)
+
+var latestAppVersionURL = struct {
+	host string
+	path string
+}{
+	host: "https://toolbox-data.anchore.io",
+	path: "/syft/releases/latest/VERSION",
+}
+
+func applicationUpdateCheck(id clio.Identification, check *options.UpdateCheck) func(cmd *cobra.Command, args []string) error {
+	return func(cmd *cobra.Command, args []string) error {
+		if check.CheckForAppUpdate {
+			checkForApplicationUpdate(id)
+		}
+		return nil
+	}
+}
+
+func checkForApplicationUpdate(id clio.Identification) {
+	log.Debugf("checking if a new version of %s is available", id.Name)
+	isAvailable, newVersion, err := isUpdateAvailable(id)
+	if err != nil {
+		// this should never stop the application
+		log.Errorf(err.Error())
+	}
+	if isAvailable {
+		log.Infof("new version of %s is available: %s (current version is %s)", id.Name, newVersion, id.Version)
+
+		bus.Publish(partybus.Event{
+			Type: event.CLIAppUpdateAvailable,
+			Value: parsers.UpdateCheck{
+				New:     newVersion,
+				Current: id.Version,
+			},
+		})
+	} else {
+		log.Debugf("no new %s update available", id.Name)
+	}
+}
+
+// isUpdateAvailable indicates if there is a newer application version available, and if so, what the new version is.
+func isUpdateAvailable(id clio.Identification) (bool, string, error) {
+	if !isProductionBuild(id.Version) {
+		// don't allow for non-production builds to check for a version.
+		return false, "", nil
+	}
+
+	currentVersion, err := hashiVersion.NewVersion(id.Version)
+	if err != nil {
+		return false, "", fmt.Errorf("failed to parse current application version: %w", err)
+	}
+
+	latestVersion, err := fetchLatestApplicationVersion(id)
+	if err != nil {
+		return false, "", err
+	}
+
+	if latestVersion.GreaterThan(currentVersion) {
+		return true, latestVersion.String(), nil
+	}
+
+	return false, "", nil
+}
+
+func isProductionBuild(version string) bool {
+	if strings.Contains(version, "SNAPSHOT") || strings.Contains(version, internal.NotProvided) {
+		return false
+	}
+	return true
+}
+
+func fetchLatestApplicationVersion(id clio.Identification) (*hashiVersion.Version, error) {
+	req, err := http.NewRequest(http.MethodGet, latestAppVersionURL.host+latestAppVersionURL.path, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request for latest version: %w", err)
+	}
+	req.Header.Add("User-Agent", fmt.Sprintf("%v %v", id.Name, id.Version))
+
+	client := http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch latest version: %w", err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("HTTP %d on fetching latest version: %s", resp.StatusCode, resp.Status)
+	}
+
+	versionBytes, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read latest version: %w", err)
+	}
+
+	versionStr := strings.TrimSuffix(string(versionBytes), "\n")
+	if len(versionStr) > 50 {
+		return nil, fmt.Errorf("version too long: %q", versionStr[:50])
+	}
+
+	return hashiVersion.NewVersion(versionStr)
+}