Manager: warn when the blender variable has no value

When the `blender` variable has no value, Flamenco will not be able to
run Blender, which is worth emitting a warning about early on.

This required a bit of a reshuffle of the configuration loading logic, to
avoid loading things twice (and thus warning twice).

Fixes part of #104366

CHANGELOG.md

@@ -11,6 +11,7 @@ bugs in actually-released versions.
 
   This happens uniformly, regardless of the platform. So also on Linux, which has a case-sensitive filesystem, this matching is done in a case-insensitive way. It is very unlikely that a Flamenco configuration has two separate variables, for paths that only differ in their case.
 - Fix issue where jobs could get stuck in `pause-requested` state. Such jobs are now also detected at startup of the Manager, and sent to `paused` when possible.
+- Log a warning at startup when the `blender` variable is missing, or has no value for one or more platforms.
 
 
 ## 3.6 - released 2024-12-01

cmd/flamenco-manager/main.go

@@ -4,9 +4,7 @@ package main
 
 import (
 	"context"
-	"errors"
 	"flag"
-	"io/fs"
 	"net"
 	"net/url"
 	"os"
@@ -117,15 +115,10 @@ func main() {
 func runFlamencoManager() bool {
 	// Load configuration.
 	configService := config.NewService()
-	err := configService.Load()
-	if err != nil && !errors.Is(err, fs.ErrNotExist) {
-		log.Error().Err(err).Msg("loading configuration")
-	}
-
 	if cliArgs.setupAssistant {
 		configService.ForceFirstRun()
 	}
-	isFirstRun, err := configService.IsFirstRun()
+	isFirstRun, err := configService.Load()
 	switch {
 	case err != nil:
 		log.Fatal().Err(err).Msg("unable to determine whether this is the first run of Flamenco or not")

internal/manager/api_impl/interfaces.go

@@ -184,8 +184,8 @@ type ConfigService interface {
 	// options (like Shaman).
 	EffectiveStoragePath() string
 
-	// IsFirstRun returns true if this is likely to be the first run of Flamenco.
-	IsFirstRun() (bool, error)
+	// Load returns true if this is likely to be the first run of Flamenco.
+	Load() (bool, error)
 
 	// ForceFirstRun forces IsFirstRun() to return true. This is used to force the
 	// setup assistant on a configured system.

internal/manager/api_impl/meta.go

@@ -39,7 +39,7 @@ func (f *Flamenco) GetVersion(e echo.Context) error {
 }
 
 func (f *Flamenco) GetConfiguration(e echo.Context) error {
-	isFirstRun, err := f.config.IsFirstRun()
+	isFirstRun, err := f.config.Load()
 	if err != nil {
 		logger := requestLogger(e)
 		logger.Error().Err(err).Msg("error investigating configuration")

internal/manager/api_impl/mocks/api_impl_mock.gen.go

@@ -953,19 +953,19 @@ func (mr *MockConfigServiceMockRecorder) Get() *gomock.Call {
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Get", reflect.TypeOf((*MockConfigService)(nil).Get))
 }
 
-// IsFirstRun mocks base method.
-func (m *MockConfigService) IsFirstRun() (bool, error) {
+// Load mocks base method.
+func (m *MockConfigService) Load() (bool, error) {
 	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "IsFirstRun")
+	ret := m.ctrl.Call(m, "Load")
 	ret0, _ := ret[0].(bool)
 	ret1, _ := ret[1].(error)
 	return ret0, ret1
 }
 
-// IsFirstRun indicates an expected call of IsFirstRun.
-func (mr *MockConfigServiceMockRecorder) IsFirstRun() *gomock.Call {
+// Load indicates an expected call of Load.
+func (mr *MockConfigServiceMockRecorder) Load() *gomock.Call {
 	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "IsFirstRun", reflect.TypeOf((*MockConfigService)(nil).IsFirstRun))
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Load", reflect.TypeOf((*MockConfigService)(nil).Load))
 }
 
 // NewVariableExpander mocks base method.

internal/manager/config/config.go

@@ -246,6 +246,7 @@ func (c *Conf) processAfterLoading(override ...func(c *Conf)) {
 	c.constructVariableLookupTable()
 	c.checkDatabase()
 	c.checkVariables()
+	c.checkBlenderVariable()
 }
 
 // MockCurrentGOOSForTests can be used in unit tests to make the variable
@@ -602,6 +603,37 @@ func (c *Conf) checkVariables() {
 	}
 }
 
+func (c *Conf) checkBlenderVariable() {
+	blenderKey := "blender"
+	blender, ok := c.Variables[blenderKey]
+	if !ok {
+		log.Error().Msg("config: variable 'blender' not found, Flamenco will not be able to run Blender")
+		return
+	}
+
+	missingPlatforms := []string{}
+	for _, value := range blender.Values {
+		if value.Value == "" {
+			missingPlatforms = append(missingPlatforms, string(value.Platform))
+		}
+	}
+
+	logger := log.With().
+		Str("filename", configFilename).
+		Logger()
+	switch len(missingPlatforms) {
+	case 0: // Fine.
+	case 1:
+		logger.Warn().
+			Str("platform", missingPlatforms[0]).
+			Msgf("config: variable %q has no value, Flamenco will not be able to run Blender on this platform", blenderKey)
+	default: // More than one missing platform.
+		logger.Warn().
+			Strs("platforms", missingPlatforms).
+			Msgf("config: variable %q has no value, Flamenco will not be able to run Blender on these platforms", blenderKey)
+	}
+}
+
 func (c *Conf) checkDatabase() {
 	c.DatabaseDSN = strings.TrimSpace(c.DatabaseDSN)
 }

internal/manager/config/service.go

@@ -22,13 +22,16 @@ func NewService() *Service {
 	}
 }
 
-// IsFirstRun returns true if this is likely to be the first run of Flamenco.
-func (s *Service) IsFirstRun() (bool, error) {
-	if s.forceFirstRun {
-		return true, nil
-	}
+func (s *Service) ForceFirstRun() {
+	s.forceFirstRun = true
+}
 
+// Load parses the flamenco-manager.yaml file, and returns whether this is
+// likely to be the first run or not.
+func (s *Service) Load() (bool, error) {
 	config, err := getConf()
+	s.config = config
+
 	switch {
 	case errors.Is(err, fs.ErrNotExist):
 		// No configuration means first run.
@@ -38,20 +41,7 @@ func (s *Service) IsFirstRun() (bool, error) {
 	}
 
 	// No shared storage configured means first run.
-	return config.SharedStoragePath == "", nil
-}
-
-func (s *Service) ForceFirstRun() {
-	s.forceFirstRun = true
-}
-
-func (s *Service) Load() error {
-	config, err := getConf()
-	if err != nil {
-		return err
-	}
-	s.config = config
-	return nil
+	return s.forceFirstRun || config.SharedStoragePath == "", nil
 }
 
 func (s *Service) Get() *Conf {