Load core faasd service definitions from compose

**What**
- Use the compose-go library to read the service definitions from an
  external compose file instead of building them in Go
- Add default compose file and copy during `faasd install`
- Add test for load and parse of compose file
- Make testing easier  by sorting the env keys
- Allow append to instantiate the slices so that we can more easily test
  for proper parsing (e.g. nil is still nil etc)
- Add the arch suffix to the compose file and set this as part of the
  env when we parse the compose file. This allows faasd to dynamically
  set the arch suffix used for the basic auth and the gateway images.

Signed-off-by: Lucas Roesler <roesler.lucas@gmail.com>

vendor/github.com/xeipuuv/gojsonschema/schemaPool.go

@@ -0,0 +1,215 @@
+// Copyright 2015 xeipuuv ( https://github.com/xeipuuv )
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// author           xeipuuv
+// author-github    https://github.com/xeipuuv
+// author-mail      xeipuuv@gmail.com
+//
+// repository-name  gojsonschema
+// repository-desc  An implementation of JSON Schema, based on IETF's draft v4 - Go language.
+//
+// description		Defines resources pooling.
+//                  Eases referencing and avoids downloading the same resource twice.
+//
+// created          26-02-2013
+
+package gojsonschema
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+
+	"github.com/xeipuuv/gojsonreference"
+)
+
+type schemaPoolDocument struct {
+	Document interface{}
+	Draft    *Draft
+}
+
+type schemaPool struct {
+	schemaPoolDocuments map[string]*schemaPoolDocument
+	jsonLoaderFactory   JSONLoaderFactory
+	autoDetect          *bool
+}
+
+func (p *schemaPool) parseReferences(document interface{}, ref gojsonreference.JsonReference, pooled bool) error {
+
+	var (
+		draft     *Draft
+		err       error
+		reference = ref.String()
+	)
+	// Only the root document should be added to the schema pool if pooled is true
+	if _, ok := p.schemaPoolDocuments[reference]; pooled && ok {
+		return fmt.Errorf("Reference already exists: \"%s\"", reference)
+	}
+
+	if *p.autoDetect {
+		_, draft, err = parseSchemaURL(document)
+		if err != nil {
+			return err
+		}
+	}
+
+	err = p.parseReferencesRecursive(document, ref, draft)
+
+	if pooled {
+		p.schemaPoolDocuments[reference] = &schemaPoolDocument{Document: document, Draft: draft}
+	}
+
+	return err
+}
+
+func (p *schemaPool) parseReferencesRecursive(document interface{}, ref gojsonreference.JsonReference, draft *Draft) error {
+	// parseReferencesRecursive parses a JSON document and resolves all $id and $ref references.
+	// For $ref references it takes into account the $id scope it is in and replaces
+	// the reference by the absolute resolved reference
+
+	// When encountering errors it fails silently. Error handling is done when the schema
+	// is syntactically parsed and any error encountered here should also come up there.
+	switch m := document.(type) {
+	case []interface{}:
+		for _, v := range m {
+			p.parseReferencesRecursive(v, ref, draft)
+		}
+	case map[string]interface{}:
+		localRef := &ref
+
+		keyID := KEY_ID_NEW
+		if existsMapKey(m, KEY_ID) {
+			keyID = KEY_ID
+		}
+		if existsMapKey(m, keyID) && isKind(m[keyID], reflect.String) {
+			jsonReference, err := gojsonreference.NewJsonReference(m[keyID].(string))
+			if err == nil {
+				localRef, err = ref.Inherits(jsonReference)
+				if err == nil {
+					if _, ok := p.schemaPoolDocuments[localRef.String()]; ok {
+						return fmt.Errorf("Reference already exists: \"%s\"", localRef.String())
+					}
+					p.schemaPoolDocuments[localRef.String()] = &schemaPoolDocument{Document: document, Draft: draft}
+				}
+			}
+		}
+
+		if existsMapKey(m, KEY_REF) && isKind(m[KEY_REF], reflect.String) {
+			jsonReference, err := gojsonreference.NewJsonReference(m[KEY_REF].(string))
+			if err == nil {
+				absoluteRef, err := localRef.Inherits(jsonReference)
+				if err == nil {
+					m[KEY_REF] = absoluteRef.String()
+				}
+			}
+		}
+
+		for k, v := range m {
+			// const and enums should be interpreted literally, so ignore them
+			if k == KEY_CONST || k == KEY_ENUM {
+				continue
+			}
+			// Something like a property or a dependency is not a valid schema, as it might describe properties named "$ref", "$id" or "const", etc
+			// Therefore don't treat it like a schema.
+			if k == KEY_PROPERTIES || k == KEY_DEPENDENCIES || k == KEY_PATTERN_PROPERTIES {
+				if child, ok := v.(map[string]interface{}); ok {
+					for _, v := range child {
+						p.parseReferencesRecursive(v, *localRef, draft)
+					}
+				}
+			} else {
+				p.parseReferencesRecursive(v, *localRef, draft)
+			}
+		}
+	}
+	return nil
+}
+
+func (p *schemaPool) GetDocument(reference gojsonreference.JsonReference) (*schemaPoolDocument, error) {
+
+	var (
+		spd   *schemaPoolDocument
+		draft *Draft
+		ok    bool
+		err   error
+	)
+
+	if internalLogEnabled {
+		internalLog("Get Document ( %s )", reference.String())
+	}
+
+	// Create a deep copy, so we can remove the fragment part later on without altering the original
+	refToURL, _ := gojsonreference.NewJsonReference(reference.String())
+
+	// First check if the given fragment is a location independent identifier
+	// http://json-schema.org/latest/json-schema-core.html#rfc.section.8.2.3
+
+	if spd, ok = p.schemaPoolDocuments[refToURL.String()]; ok {
+		if internalLogEnabled {
+			internalLog(" From pool")
+		}
+		return spd, nil
+	}
+
+	// If the given reference is not a location independent identifier,
+	// strip the fragment and look for a document with it's base URI
+
+	refToURL.GetUrl().Fragment = ""
+
+	if cachedSpd, ok := p.schemaPoolDocuments[refToURL.String()]; ok {
+		document, _, err := reference.GetPointer().Get(cachedSpd.Document)
+
+		if err != nil {
+			return nil, err
+		}
+
+		if internalLogEnabled {
+			internalLog(" From pool")
+		}
+
+		spd = &schemaPoolDocument{Document: document, Draft: cachedSpd.Draft}
+		p.schemaPoolDocuments[reference.String()] = spd
+
+		return spd, nil
+	}
+
+	// It is not possible to load anything remotely that is not canonical...
+	if !reference.IsCanonical() {
+		return nil, errors.New(formatErrorDescription(
+			Locale.ReferenceMustBeCanonical(),
+			ErrorDetails{"reference": reference.String()},
+		))
+	}
+
+	jsonReferenceLoader := p.jsonLoaderFactory.New(reference.String())
+	document, err := jsonReferenceLoader.LoadJSON()
+
+	if err != nil {
+		return nil, err
+	}
+
+	// add the whole document to the pool for potential re-use
+	p.parseReferences(document, refToURL, true)
+
+	_, draft, _ = parseSchemaURL(document)
+
+	// resolve the potential fragment and also cache it
+	document, _, err = reference.GetPointer().Get(document)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return &schemaPoolDocument{Document: document, Draft: draft}, nil
+}