Add option to configure template job HCL file

Previously, the template job HCL file was hardcoded using go:embed
in the binary. However, this did not allow users running Poseidon
to change its content. Now, users can change the content of the
template job HCL file using the configuration option.

cmd/poseidon/main.go

@@ -51,7 +51,11 @@ func initServer() *http.Server {
 	}
 
 	runnerManager := runner.NewNomadRunnerManager(nomadAPIClient, context.Background())
-	environmentManager := environment.NewNomadEnvironmentManager(runnerManager, nomadAPIClient)
+	environmentManager, err := environment.
+		NewNomadEnvironmentManager(runnerManager, nomadAPIClient, config.Config.Server.TemplateJobFile)
+	if err != nil {
+		log.WithError(err).Fatal("Error initializing environment manager")
+	}
 
 	return &http.Server{
 		Addr:         config.Config.Server.URL().Host,

configuration.example.yaml

@@ -16,6 +16,8 @@ server:
     keyfile: ./poseidon.key
   # If true, an additional WebSocket connection will be opened to split stdout and stderr when executing interactively
   interactiveStderr: true
+  # If set, the file at the given path overwrites the default Nomad job file in internal/environment/template-environment-job.hcl
+  templateJobFile: ./poseidon.hcl
 
 # Configuration of the used Nomad cluster
 nomad:

internal/config/config.go

@@ -28,6 +28,7 @@ var (
 				KeyFile:  "",
 			},
 			InteractiveStderr: true,
+			TemplateJobFile:   "",
 		},
 		Nomad: Nomad{
 			Address: "127.0.0.1",
@@ -63,6 +64,7 @@ type server struct {
 	Token             string
 	TLS               TLS
 	InteractiveStderr bool
+	TemplateJobFile   string
 }
 
 // URL returns the URL of the Poseidon webserver.

internal/environment/manager.go

@@ -10,6 +10,7 @@ import (
 	"gitlab.hpi.de/codeocean/codemoon/poseidon/internal/runner"
 	"gitlab.hpi.de/codeocean/codemoon/poseidon/pkg/dto"
 	"gitlab.hpi.de/codeocean/codemoon/poseidon/pkg/logging"
+	"os"
 	"strconv"
 )
 
@@ -39,13 +40,35 @@ type Manager interface {
 func NewNomadEnvironmentManager(
 	runnerManager runner.Manager,
 	apiClient nomad.ExecutorAPI,
-) *NomadEnvironmentManager {
-	m := &NomadEnvironmentManager{runnerManager, apiClient, *parseJob(templateEnvironmentJobHCL)}
+	templateJobFile string,
+) (*NomadEnvironmentManager, error) {
+	if err := loadTemplateEnvironmentJobHCL(templateJobFile); err != nil {
+		return nil, err
+	}
+	templateEnvironmentJob, err := parseJob(templateEnvironmentJobHCL)
+	if err != nil {
+		return nil, err
+	}
+	m := &NomadEnvironmentManager{runnerManager, apiClient, *templateEnvironmentJob}
 	if err := m.Load(); err != nil {
 		log.WithError(err).Error("Error recovering the execution environments")
 	}
 	runnerManager.Load()
-	return m
+	return m, nil
+}
+
+// loadTemplateEnvironmentJobHCL loads the template environment job HCL from the given path.
+// If the path is empty, the embedded default file is used.
+func loadTemplateEnvironmentJobHCL(path string) error {
+	if path == "" {
+		return nil
+	}
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return fmt.Errorf("error loading template environment job: %w", err)
+	}
+	templateEnvironmentJobHCL = string(data)
+	return nil
 }
 
 type NomadEnvironmentManager struct {
@@ -116,7 +139,7 @@ func (m *NomadEnvironmentManager) Load() error {
 	return nil
 }
 
-func parseJob(jobHCL string) *nomadApi.Job {
+func parseJob(jobHCL string) (*nomadApi.Job, error) {
 	config := jobspec2.ParseConfig{
 		Body:    []byte(jobHCL),
 		AllowFS: false,
@@ -124,9 +147,8 @@ func parseJob(jobHCL string) *nomadApi.Job {
 	}
 	job, err := jobspec2.ParseWithConfig(&config)
 	if err != nil {
-		log.WithError(err).Fatal("Error parsing Nomad job")
-		return nil
+		return nil, fmt.Errorf("error parsing Nomad job: %w", err)
 	}
 
-	return job
+	return job, nil
 }

internal/environment/manager_test.go

@@ -2,15 +2,15 @@ package environment
 
 import (
 	nomadApi "github.com/hashicorp/nomad/api"
-	"github.com/sirupsen/logrus"
-	"github.com/sirupsen/logrus/hooks/test"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/require"
 	"github.com/stretchr/testify/suite"
 	"gitlab.hpi.de/codeocean/codemoon/poseidon/internal/nomad"
 	"gitlab.hpi.de/codeocean/codemoon/poseidon/internal/runner"
 	"gitlab.hpi.de/codeocean/codemoon/poseidon/pkg/dto"
 	"gitlab.hpi.de/codeocean/codemoon/poseidon/tests"
+	"os"
 	"testing"
 )
 
@@ -119,24 +119,66 @@ func (s *CreateOrUpdateTestSuite) TestReturnsFalseIfCreatesOrUpdateEnvironmentRe
 }
 
 func TestParseJob(t *testing.T) {
-	exited := false
-	logger, hook := test.NewNullLogger()
-	logger.ExitFunc = func(i int) {
-		exited = true
-	}
-
-	log = logger.WithField("pkg", "nomad")
-
 	t.Run("parses the given default job", func(t *testing.T) {
-		job := parseJob(templateEnvironmentJobHCL)
-		assert.False(t, exited)
+		job, err := parseJob(templateEnvironmentJobHCL)
+		assert.NoError(t, err)
 		assert.NotNil(t, job)
 	})
 
-	t.Run("fatals when given wrong job", func(t *testing.T) {
-		job := parseJob("")
-		assert.True(t, exited)
+	t.Run("returns error when given wrong job", func(t *testing.T) {
+		job, err := parseJob("")
+		assert.Error(t, err)
 		assert.Nil(t, job)
-		assert.Equal(t, logrus.FatalLevel, hook.LastEntry().Level)
 	})
 }
+
+func TestNewNomadEnvironmentManager(t *testing.T) {
+	executorAPIMock := &nomad.ExecutorAPIMock{}
+	executorAPIMock.On("LoadEnvironmentJobs").Return([]*nomadApi.Job{}, nil)
+
+	runnerManagerMock := &runner.ManagerMock{}
+	runnerManagerMock.On("Load").Return()
+
+	previousTemplateEnvironmentJobHCL := templateEnvironmentJobHCL
+
+	t.Run("returns error if template file does not exist", func(t *testing.T) {
+		_, err := NewNomadEnvironmentManager(runnerManagerMock, executorAPIMock, "/non-existent/file")
+		assert.Error(t, err)
+	})
+
+	t.Run("loads template environment job from file", func(t *testing.T) {
+		templateJobHCL := "job \"test\" {}"
+		expectedJob, err := parseJob(templateJobHCL)
+		require.NoError(t, err)
+		f := createTempFile(t, templateJobHCL)
+		defer os.Remove(f.Name())
+
+		m, err := NewNomadEnvironmentManager(runnerManagerMock, executorAPIMock, f.Name())
+		assert.NoError(t, err)
+		assert.NotNil(t, m)
+		assert.Equal(t, templateJobHCL, templateEnvironmentJobHCL)
+		assert.Equal(t, *expectedJob, m.templateEnvironmentJob)
+	})
+
+	t.Run("returns error if template file is invalid", func(t *testing.T) {
+		templateJobHCL := "invalid hcl file"
+		f := createTempFile(t, templateJobHCL)
+		defer os.Remove(f.Name())
+
+		_, err := NewNomadEnvironmentManager(runnerManagerMock, executorAPIMock, f.Name())
+		assert.Error(t, err)
+	})
+
+	templateEnvironmentJobHCL = previousTemplateEnvironmentJobHCL
+}
+
+func createTempFile(t *testing.T, content string) *os.File {
+	t.Helper()
+	f, err := os.CreateTemp("", "test")
+	require.NoError(t, err)
+	n, err := f.WriteString(content)
+	require.NoError(t, err)
+	require.Equal(t, len(content), n)
+
+	return f
+}