Initial delivery of metrics code (#81)

* Initial delivery of metrics code

* Fix build issues

* Fix build issue with go vet

vendor/github.com/prometheus/common/config/tls_config_test.go

@@ -0,0 +1,62 @@
+// Copyright 2016 The Prometheus Authors
+// 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.
+
+package config
+
+import (
+	"crypto/tls"
+	"io/ioutil"
+	"reflect"
+	"testing"
+
+	"gopkg.in/yaml.v2"
+)
+
+// LoadTLSConfig parses the given YAML file into a tls.Config.
+func LoadTLSConfig(filename string) (*tls.Config, error) {
+	content, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	cfg := TLSConfig{}
+	if err = yaml.UnmarshalStrict(content, &cfg); err != nil {
+		return nil, err
+	}
+	return NewTLSConfig(&cfg)
+}
+
+var expectedTLSConfigs = []struct {
+	filename string
+	config   *tls.Config
+}{
+	{
+		filename: "tls_config.empty.good.yml",
+		config:   &tls.Config{},
+	}, {
+		filename: "tls_config.insecure.good.yml",
+		config:   &tls.Config{InsecureSkipVerify: true},
+	},
+}
+
+func TestValidTLSConfig(t *testing.T) {
+	for _, cfg := range expectedTLSConfigs {
+		cfg.config.BuildNameToCertificate()
+		got, err := LoadTLSConfig("testdata/" + cfg.filename)
+		if err != nil {
+			t.Errorf("Error parsing %s: %s", cfg.filename, err)
+		}
+		if !reflect.DeepEqual(*got, *cfg.config) {
+			t.Fatalf("%v: unexpected config result: \n\n%v\n expected\n\n%v", cfg.filename, got, cfg.config)
+		}
+	}
+}