[WIP] Azure instance attributes from metadata endpoint

client/fingerprint/env_azure.go

@@ -0,0 +1,107 @@
+package fingerprint
+
+import (
+	"github.com/hashicorp/go-cleanhttp"
+	"github.com/hashicorp/nomad/client/config"
+	"github.com/hashicorp/nomad/nomad/structs"
+	"log"
+	"net/http"
+	"os"
+	"time"
+	"fmt"
+)
+
+// Details: https://docs.microsoft.com/en-us/azure/virtual-machines/virtual-machines-instancemetadataservice-overview
+const DEFAULT_AZURE_API_VERSION = "2017-03-01"
+const DEFAULT_AZURE_URL = "http://169.254.169.254/metadata/instance?api-version=" + DEFAULT_AZURE_API_VERSION
+
+type AzureMetadataNetworkInterface struct {
+	AccessConfigs []struct {
+		ExternalIp string
+		Type       string
+	}
+	ForwardedIps []string
+	Ip           string
+	Network      string
+}
+
+type AzureReqError struct {
+	StatusCode int
+}
+
+func (e AzureReqError) Error() string {
+	return http.StatusText(e.StatusCode)
+}
+
+type EnvAzureFingerprint struct {
+	StaticFingerprinter
+	client      *http.Client
+	logger      *log.Logger
+	metadataURL string
+}
+
+func NewEnvAzureFingerprint(logger *log.Logger) Fingerprint {
+	// Read the internal metadata URL from the environment, allowing test files to
+	// provide their own
+	metadataURL := os.Getenv("AZURE_ENV_URL")
+	if metadataURL == "" {
+		metadataURL = DEFAULT_AZURE_URL
+	}
+
+	// assume 2 seconds is enough time for inside Azure network
+	client := &http.Client{
+		Timeout:   2 * time.Second,
+		Transport: cleanhttp.DefaultTransport(),
+	}
+
+	return &EnvAzureFingerprint{
+		client:      client,
+		logger:      logger,
+		metadataURL: metadataURL,
+	}
+}
+
+func (f *EnvAzureFingerprint) Get(attribute string, isText bool) {
+	// By default; return JSON
+
+	// unless specifically mentioned to be Text
+
+}
+// Mapping of Azure Compute Units (ACUs); IO, Network refer to below:
+// https://docs.microsoft.com/en-us/azure/virtual-machines/virtual-machines-windows-sizes
+func (f *EnvAzureFingerprint) Fingerprint(cfg *config.Config, node *structs.Node) (bool, error) {
+
+	if !f.isAzure() {
+		return false, nil
+	}
+
+	if node.Links == nil {
+		node.Links = make(map[string]string)
+	}
+	// Keys and whether they should be namespaced as unique. Any key whose value
+	// uniquely identifies a node, such as ip, should be marked as unique. When
+	// marked as unique, the key isn't included in the computed node class.
+	keys := map[string]bool{
+		"vm-id":                          true,
+		"vm-size":                        false,
+		"os-type":                        false,
+		"local-ipv4":                     true,
+		"public-ipv4":                    true,
+		"placement/update-domain":        false,
+		"placement/fault-domain":         false,
+		"scheduling/automatic-restart":   false,
+		"scheduling/on-host-maintenance": false,
+	}
+
+	fmt.Printf("%v", keys)
+
+	return false, nil
+}
+
+func (f *EnvAzureFingerprint) isAzure() bool {
+	// Call the instance name; if returns something; consider that it is proxy for Azure
+	// any other way?
+
+	f.client.Get()
+	return false
+}