Snowblock API v0

Implemented the API v0 that serves as the reference for the legacy
Python (backwards compatible) implementation with the following
interfaces and types:

- <I> `Snowblock`
- <T> `Task`
- <I> `TaskConfiguration`
- <I> `TaskRegistry`
- <I> `TaskRunner`

Note that API v0 is a legacy implementation to keep the compatibility
with the original Python implementation and will be superseded with
API v1 with snowsaw version 1.0.0!

Epic GH-33
Resolves GH-70

Author: arcticicestudio

pkg/api/snowblock/constants.go

@@ -0,0 +1,20 @@
+// Copyright (C) 2017-present Arctic Ice Studio <[email protected]>
+// Copyright (C) 2017-present Sven Greb <[email protected]>
+//
+// Project:    snowsaw
+// Repository: https://github.com/arcticicestudio/snowsaw
+// License:    MIT
+
+// Author: Arctic Ice Studio <[email protected]>
+// Author: Sven Greb <[email protected]>
+// Since: 0.4.0
+
+package snowblock
+
+const (
+	// ConfigurationFileName is the name of a snowblock configuration file.
+	ConfigurationFileName = "snowblock"
+
+	// Version is the version of the snowblock API.
+	Version int = 0
+)

pkg/api/snowblock/registry.go

@@ -0,0 +1,21 @@
+// Copyright (C) 2017-present Arctic Ice Studio <[email protected]>
+// Copyright (C) 2017-present Sven Greb <[email protected]>
+//
+// Project:    snowsaw
+// Repository: https://github.com/arcticicestudio/snowsaw
+// License:    MIT
+
+// Author: Arctic Ice Studio <[email protected]>
+// Author: Sven Greb <[email protected]>
+// Since: 0.4.0
+
+package snowblock
+
+// TaskRegistry is a registry for available task runner.
+type TaskRegistry interface {
+	// Add validates and adds the given task runner to the registry.
+	Add(TaskRunner) error
+
+	// GetAll returns a list of all currently registered task runners.
+	GetAll() map[string]TaskRunner
+}

pkg/api/snowblock/runner.go

@@ -0,0 +1,22 @@
+// Copyright (C) 2017-present Arctic Ice Studio <[email protected]>
+// Copyright (C) 2017-present Sven Greb <[email protected]>
+//
+// Project:    snowsaw
+// Repository: https://github.com/arcticicestudio/snowsaw
+// License:    MIT
+
+// Author: Arctic Ice Studio <[email protected]>
+// Author: Sven Greb <[email protected]>
+// Since: 0.4.0
+
+package snowblock
+
+// TaskRunner processes a specific task.
+type TaskRunner interface {
+	// GetTaskName returns the name of the task this runner can process.
+	GetTaskName() string
+
+	// Run processes a task using the given task instructions.
+	// The snowblockPath parameter is the path of the snowblock used as contextual information.
+	Run(instructions TaskConfiguration, snowblockPath string) error
+}

pkg/api/snowblock/snowblock.go

@@ -0,0 +1,27 @@
+// Copyright (C) 2017-present Arctic Ice Studio <[email protected]>
+// Copyright (C) 2017-present Sven Greb <[email protected]>
+//
+// Project:    snowsaw
+// Repository: https://github.com/arcticicestudio/snowsaw
+// License:    MIT
+
+// Author: Arctic Ice Studio <[email protected]>
+// Author: Sven Greb <[email protected]>
+// Since: 0.4.0
+
+// Package snowblock provides the snowblock API.
+//
+// Note: API v0 is a legacy implementation to keep the compatibility with the original Python implementation and will be
+// superseded with API v1 with snowsaw version 1.0.0!
+package snowblock
+
+// Snowblock represents a snowblock.
+type Snowblock interface {
+	// Dispatch handles the processing of the snowblock by dispatching the configured TaskConfiguration to a registered
+	// TaskRunner that can handle it.
+	Dispatch() error
+
+	// Validate ensures the snowblock exists and the configuration is valid.
+	// The taskRunner parameter is a map of registered task runners that are able to process the task instructions.
+	Validate(taskRunner map[string]TaskRunner) error
+}

pkg/api/snowblock/task.go

@@ -0,0 +1,18 @@
+// Copyright (C) 2017-present Arctic Ice Studio <[email protected]>
+// Copyright (C) 2017-present Sven Greb <[email protected]>
+//
+// Project:    snowsaw
+// Repository: https://github.com/arcticicestudio/snowsaw
+// License:    MIT
+
+// Author: Arctic Ice Studio <[email protected]>
+// Author: Sven Greb <[email protected]>
+// Since: 0.4.0
+
+package snowblock
+
+// Task represents a single task of a snowblock configuration.
+type Task map[string]interface{}
+
+// TaskConfiguration represents the configuration of a single task.
+type TaskConfiguration interface{}