Fail cache status on empty results (#257)

Previously, grype-db cache status would exit zero in a few situations that
should have failed validation. Specifically, if the cached results had zero rows,
or if "-p some-provider" was passed, but "some-provider" no cache for
"some-provider" was present on disk, the command would exit zero. Instead,
exit non-zero if a provider is explicitly requested on the command line but
missing, and add a --min-rows option that defaults to zero, so that providers
with zero rows fail validation. If zero rows is acceptable, "--min-rows -1" can
be passed.

Signed-off-by: Will Murphy <will.murphy@anchore.com>

cmd/grype-db/cli/commands/cache_status.go

@@ -3,6 +3,7 @@ package commands
 import (
 	"fmt"
 	"os"
+	"strings"
 	"time"
 
 	"github.com/gookit/color"
@@ -13,7 +14,6 @@ import (
 
 	"github.com/anchore/grype-db/cmd/grype-db/application"
 	"github.com/anchore/grype-db/cmd/grype-db/cli/options"
-	"github.com/anchore/grype-db/internal/log"
 	"github.com/anchore/grype-db/pkg/provider"
 	"github.com/anchore/grype-db/pkg/provider/entry"
 )
@@ -25,9 +25,15 @@ type cacheStatusConfig struct {
 		options.Store     `yaml:",inline" mapstructure:",squash"`
 		options.Selection `yaml:",inline" mapstructure:",squash"`
 	} `yaml:"provider" json:"provider" mapstructure:"provider"`
+	minRows int64 `yaml:"min-rows" mapstructure:"min-rows"`
 }
 
 func (o *cacheStatusConfig) AddFlags(flags *pflag.FlagSet) {
+	flags.Int64VarP(
+		&o.minRows,
+		"min-rows", "", o.minRows,
+		"fail validation unless more than this many rows are present in the provider results",
+	)
 	options.AddAllFlags(flags, &o.Provider.Store, &o.Provider.Selection)
 }
 
@@ -63,22 +69,12 @@ func cacheStatus(cfg cacheStatusConfig) error {
 		return err
 	}
 
-	if len(providerNames) == 0 {
-		fmt.Println("no provider state cache found")
-		return nil
-	}
+	providerNames, missingProvidersErr := validateRequestedProviders(providerNames, cfg.Provider.IncludeFilter)
 
 	var sds []*provider.State
 	var errs []error
 
-	allowableProviders := strset.New(cfg.Provider.IncludeFilter...)
-
 	for _, name := range providerNames {
-		if allowableProviders.Size() > 0 && !allowableProviders.Has(name) {
-			log.WithFields("provider", name).Trace("skipping...")
-			continue
-		}
-
 		workspace := provider.NewWorkspace(cfg.Provider.Root, name)
 		sd, err := workspace.ReadState()
 		if err != nil {
@@ -115,10 +111,13 @@ func cacheStatus(cfg cacheStatusConfig) error {
 
 		if sd != nil {
 			name = sd.Provider
-			count, err = entry.Count(sd.Store, sd.ResultPaths())
+			counter := func() (int64, error) {
+				return entry.Count(sd.Store, sd.ResultPaths())
+			}
+			count, err = validateCount(cfg, counter)
 			if err != nil {
 				isValid = false
-				validMsg = fmt.Sprintf("INVALID (unable to count entries: %s)", err.Error())
+				validMsg = fmt.Sprintf("INVALID (%s)", err.Error())
 			}
 		}
 
@@ -135,13 +134,51 @@ func cacheStatus(cfg cacheStatusConfig) error {
 		fmt.Printf("    └── status:  %s\n", statusFmt.Sprint(validMsg))
 	}
 
+	if missingProvidersErr != nil {
+		success = false
+		fmt.Printf("INVALID (%s)\n", missingProvidersErr.Error())
+	}
+
 	if !success {
 		os.Exit(1)
 	}
 
 	return nil
 }
 
+func validateCount(cfg cacheStatusConfig, counter func() (int64, error)) (int64, error) {
+	count, err := counter()
+	if err != nil {
+		return 0, fmt.Errorf("unable to count entries: %w", err)
+	}
+	if count <= cfg.minRows {
+		return 0, fmt.Errorf("data has %d rows, must have more than %d", count, cfg.minRows)
+	}
+	return count, nil
+}
+
+// validateRequestedProviders takes the set of providers found on disk, and the set of providers
+// requested at the command line. It returns the subset of providers on disk that were requested.
+// If providers were requested that are not present on disk, it returns an error.
+// If no providers are explicitly requested, it returns the entire set.
+func validateRequestedProviders(providersOnDisk []string, requestedProviders []string) ([]string, error) {
+	if len(requestedProviders) == 0 {
+		return providersOnDisk, nil
+	}
+	var result []string
+	requestedSet := strset.New(requestedProviders...)
+	for _, p := range providersOnDisk {
+		if requestedSet.Has(p) {
+			result = append(result, p)
+			requestedSet.Remove(p)
+		}
+	}
+	if requestedSet.Size() > 0 {
+		return nil, fmt.Errorf("providers requested but not present on disk: %s", strings.Join(requestedSet.List(), ", "))
+	}
+	return result, nil
+}
+
 func readProviderNamesFromRoot(root string) ([]string, error) {
 	// list all the directories in "root"
 	listing, err := os.ReadDir(root)

cmd/grype-db/cli/commands/cache_status_test.go

@@ -0,0 +1,101 @@
+package commands
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_validateCount(t *testing.T) {
+	tests := []struct {
+		name    string
+		cfg     cacheStatusConfig
+		counter func() (int64, error)
+		want    int64
+		wantErr assert.ErrorAssertionFunc
+	}{
+		{
+			name: "empty count passes when min-rows is -1",
+			cfg:  cacheStatusConfig{minRows: -1},
+			counter: func() (int64, error) {
+				return 0, nil
+			},
+		},
+		{
+			name: "empty count fails when min-rows is 0",
+			cfg:  cacheStatusConfig{minRows: 0},
+			counter: func() (int64, error) {
+				return 0, nil
+			},
+			wantErr: assert.Error,
+		},
+		{
+			name: "large count passes when min-rows is less",
+			cfg:  cacheStatusConfig{minRows: 12},
+			counter: func() (int64, error) {
+				return 13, nil
+			},
+			want: 13,
+		},
+		{
+			name: "error is reported when counter returns error",
+			counter: func() (int64, error) {
+				return 0, fmt.Errorf("could not count records")
+			},
+			wantErr: assert.Error,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.wantErr == nil {
+				tt.wantErr = assert.NoError
+			}
+			count, err := validateCount(tt.cfg, tt.counter)
+			if !tt.wantErr(t, err) {
+				return
+			}
+			assert.Equal(t, tt.want, count)
+		})
+	}
+}
+
+func Test_validateRequestedProviders(t *testing.T) {
+	tests := []struct {
+		name               string
+		providersOnDisk    []string
+		requestedProviders []string
+		want               []string
+		wantErr            assert.ErrorAssertionFunc
+	}{
+		{
+			name:            "no requested providers means on disk state is ok",
+			providersOnDisk: []string{"alpine", "some-provider", "void-linux", "gentoo"},
+			want:            []string{"alpine", "some-provider", "void-linux", "gentoo"},
+		},
+		{
+			name:               "requesting subset of providers works",
+			providersOnDisk:    []string{"alpine", "some-provider", "void-linux", "gentoo"},
+			requestedProviders: []string{"alpine", "void-linux"},
+			want:               []string{"alpine", "void-linux"},
+		},
+		{
+			name:               "requesting missing provider result in error",
+			providersOnDisk:    []string{"alpine", "some-provider", "void-linux", "gentoo"},
+			requestedProviders: []string{"alpine", "void-linux", "missing"},
+			wantErr:            assert.Error,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := validateRequestedProviders(tt.providersOnDisk, tt.requestedProviders)
+			if tt.wantErr == nil {
+				tt.wantErr = assert.NoError
+			}
+			if !tt.wantErr(t, err, fmt.Sprintf("validateRequestedProviders(%v, %v)", tt.providersOnDisk, tt.requestedProviders)) {
+				return
+			}
+			assert.Equalf(t, tt.want, got, "validateRequestedProviders(%v, %v)", tt.providersOnDisk, tt.requestedProviders)
+		})
+	}
+}