def/task.go

@@ -20,6 +20,7 @@ package def
 
 import (
 	"encoding/json"
+	"github.com/spdfg/elektron/utilities/validation"
 	"os"
 
 	mesos "github.com/mesos/mesos-go/api/v0/mesosproto"
@@ -55,6 +56,18 @@ func TasksFromJSON(uri string) ([]Task, error) {
 		return nil, errors.Wrap(err, "Error unmarshalling")
 	}
 
+	// Validating task definitions.
+	for _, task := range tasks {
+		err := validation.Validate("invalid task definition",
+			ValidatorForTask(task,
+				withNameValidator(),
+				withImageValidator(),
+				withResourceValidator()))
+		if err != nil {
+			return tasks, err
+		}
+	}
+
 	initTaskResourceRequirements(tasks)
 	return tasks, nil
 }

def/taskValidators.go

@@ -0,0 +1,91 @@
+// Copyright (C) 2018 spdfg
+//
+// This file is part of Elektron.
+//
+// Elektron is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Elektron is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Elektron.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+package def
+
+import (
+	"github.com/pkg/errors"
+	"github.com/spdfg/elektron/utilities/validation"
+	"regexp"
+)
+
+// taskValidator is a validator that validates one or more attributes of a task.
+type taskValidator func(Task) error
+
+// ValidatorForTask returns a validator that runs all provided taskValidators and
+// returns an error corresponding to the first taskValidator that failed.
+func ValidatorForTask(t Task, taskValidators ...taskValidator) validation.Validator {
+	return func() error {
+		for _, tv := range taskValidators {
+			if err := tv(t); err != nil {
+				return err
+			}
+		}
+
+		return nil
+	}
+}
+
+// withNameValidator returns a taskValidator that checks whether the task name is valid.
+func withNameValidator() taskValidator {
+	return func(t Task) error {
+		// Task name cannot be empty string.
+		if t.Name == "" {
+			return errors.New("task name cannot be empty string")
+		}
+
+		// Task name cannot contain tabs or spaces.
+		matched, _ := regexp.MatchString("\\t+|\\s+", t.Name)
+		if matched {
+			return errors.New("task name cannot contain tabs or spaces")
+		}
+
+		return nil
+	}
+}
+
+// withResourceValidator returns a taskValidator that checks whether the resource requirements are valid.
+// Currently, only requirements for traditional resources (cpu and memory) are validated.
+func withResourceValidator() taskValidator {
+	return func(t Task) error {
+		// CPU value cannot be 0.
+		if t.CPU == 0.0 {
+			return errors.New("cpu resource for task cannot be 0")
+		}
+
+		// RAM value cannot be 0.
+		if t.RAM == 0.0 {
+			return errors.New("memory resource for task cannot be 0")
+		}
+
+		return nil
+	}
+}
+
+// withImageValidator returns a taskValidator that checks whether a valid image has been
+// provided for the task.
+func withImageValidator() taskValidator {
+	return func(t Task) error {
+		// Image cannot be empty.
+		if t.Image == "" {
+			return errors.New("valid image needs to be provided for task")
+		}
+
+		return nil
+	}
+}

def/taskValidators_test.go

@@ -0,0 +1,75 @@
+// Copyright (C) 2018 spdfg
+//
+// This file is part of Elektron.
+//
+// Elektron is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Elektron is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Elektron.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+package def
+
+import (
+	"github.com/spdfg/elektron/utilities/validation"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestValidatorForTask(t *testing.T) {
+	getValidator := func(t Task) validation.Validator {
+		return ValidatorForTask(t,
+			withNameValidator(),
+			withImageValidator(),
+			withResourceValidator())
+	}
+
+	test := func(task Task, expectErr bool, message string) {
+		validator := getValidator(task)
+		if expectErr {
+			assert.Error(t, validation.Validate(message, validator))
+		} else {
+			assert.NoError(t, validation.Validate(message, validator))
+		}
+	}
+
+	inst := 10
+	validTask := Task{
+		Name:      "minife",
+		CPU:       3.0,
+		RAM:       4096,
+		Watts:     50,
+		Image:     "rdelvalle/minife:electron1",
+		CMD:       "cd src && mpirun -np 1 miniFE.x -nx 100 -ny 100 -nz 100",
+		Instances: &inst,
+	}
+	test(validTask, false, "invalid task definition")
+	// Task with empty name.
+	invalidTaskEmptyName := validTask
+	invalidTaskEmptyName.Name = ""
+	test(invalidTaskEmptyName, true, "invalid task definition")
+	// Task with name that contains spaces.
+	invalidTaskNameWithSpaces := validTask
+	invalidTaskNameWithSpaces.Name = "my task"
+	test(invalidTaskNameWithSpaces, true, "invalid task definition")
+	// Task with invalid image.
+	invalidTaskImage := validTask
+	invalidTaskImage.Image = ""
+	test(invalidTaskImage, true, "invalid task definition")
+	// Task with invalid cpu resources.
+	invalidTaskResourcesCPU := validTask
+	invalidTaskResourcesCPU.CPU = 0
+	test(invalidTaskResourcesCPU, true, "invalid task definition")
+	// Task with invalid memory resources.
+	invalidTaskResourcesRAM := validTask
+	invalidTaskResourcesRAM.RAM = 0
+	test(invalidTaskResourcesRAM, true, "invalid task definition")
+}

scheduler.go

@@ -208,7 +208,7 @@ func main() {
 	}
 	tasks, err := def.TasksFromJSON(*tasksFile)
 	if err != nil || len(tasks) == 0 {
-		log.Fatal("Invalid tasks specification file provided.")
+		log.Fatal(err)
 	}
 	schedOptions = append(schedOptions, schedulers.WithTasks(tasks))
 

utilities/validation/validate.go

@@ -0,0 +1,40 @@
+// Copyright (C) 2018 spdfg
+//
+// This file is part of Elektron.
+//
+// Elektron is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Elektron is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Elektron.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+// Package validation contains utilities to help run validators.
+package validation
+
+import "github.com/pkg/errors"
+
+// Validator is a function that performs some sort of validation.
+// To keep things generic, this function does not accept any arguments.
+// In practice, a validator could be a closure.
+type Validator func() error
+
+// Validate a list of validators.
+// If validation fails, then wrap the returned error with the given base
+// error message.
+func Validate(baseErrMsg string, validators ...Validator) error {
+	for _, v := range validators {
+		if err := v(); err != nil {
+			return errors.Wrap(err, baseErrMsg)
+		}
+	}
+
+	return nil
+}