Fix host authentication errors in case of DB failure (#1512)

Closes #1511

server/datastore/mysql/hosts.go

@@ -470,7 +470,7 @@ func (d *Datastore) AuthenticateHost(nodeKey string) (*kolide.Host, error) {
 	if err := d.db.Get(host, sqlStatement, nodeKey); err != nil {
 		switch err {
 		case sql.ErrNoRows:
-			return nil, errors.Wrap(err, "host not found")
+			return nil, notFound("Host")
 		default:
 			return nil, errors.New("finding host")
 		}

server/mock/datastore_hosts.go

@@ -21,7 +21,6 @@ type HostFunc func(id uint) (*kolide.Host, error)
 type ListHostsFunc func(opt kolide.ListOptions) ([]*kolide.Host, error)
 
 type EnrollHostFunc func(osqueryHostId string, nodeKeySize int) (*kolide.Host, error)
-
 type AuthenticateHostFunc func(nodeKey string) (*kolide.Host, error)
 
 type MarkHostSeenFunc func(host *kolide.Host, t time.Time) error

server/service/service_osquery.go

@@ -39,9 +39,16 @@ func (svc service) AuthenticateHost(ctx context.Context, nodeKey string) (*kolid
 
 	host, err := svc.ds.AuthenticateHost(nodeKey)
 	if err != nil {
-		return nil, osqueryError{
-			message:     "authentication error: " + err.Error(),
-			nodeInvalid: true,
+		switch err.(type) {
+		case kolide.NotFoundError:
+			return nil, osqueryError{
+				message:     "authentication error: invalid node key: " + nodeKey,
+				nodeInvalid: true,
+			}
+		default:
+			return nil, osqueryError{
+				message: "authentication error: " + err.Error(),
+			}
 		}
 	}
 

server/service/service_osquery_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"strings"
@@ -933,3 +934,52 @@ func setupOsqueryTests(t *testing.T) (kolide.Datastore, kolide.Service, *clock.M
 
 	return ds, svc, mockClock
 }
+
+type notFoundError struct{}
+
+func (e notFoundError) Error() string {
+	return "not found"
+}
+
+func (e notFoundError) IsNotFound() bool {
+	return true
+}
+
+func TestAuthenticationErrors(t *testing.T) {
+	ms := new(mock.Store)
+	ms.MarkHostSeenFunc = func(*kolide.Host, time.Time) error {
+		return nil
+	}
+	ms.AuthenticateHostFunc = func(nodeKey string) (*kolide.Host, error) {
+		return nil, nil
+	}
+
+	svc, err := newTestService(ms, nil)
+	require.Nil(t, err)
+	ctx := context.Background()
+
+	_, err = svc.AuthenticateHost(ctx, "")
+	require.NotNil(t, err)
+	require.True(t, err.(osqueryError).NodeInvalid())
+
+	_, err = svc.AuthenticateHost(ctx, "foo")
+	require.Nil(t, err)
+
+	// return not found error
+	ms.AuthenticateHostFunc = func(nodeKey string) (*kolide.Host, error) {
+		return nil, notFoundError{}
+	}
+
+	_, err = svc.AuthenticateHost(ctx, "foo")
+	require.NotNil(t, err)
+	require.True(t, err.(osqueryError).NodeInvalid())
+
+	// return other error
+	ms.AuthenticateHostFunc = func(nodeKey string) (*kolide.Host, error) {
+		return nil, errors.New("foo")
+	}
+
+	_, err = svc.AuthenticateHost(ctx, "foo")
+	require.NotNil(t, err)
+	require.False(t, err.(osqueryError).NodeInvalid())
+}