Add supports for stats in ACI provider

This adds a new, optional, interface for providers that want to provide
stats.

providers/azure/client/aci/client.go

@@ -18,6 +18,7 @@ const (
 	containerGroupListByResourceGroupURLPath = "subscriptions/{{.subscriptionId}}/resourceGroups/{{.resourceGroup}}/providers/Microsoft.ContainerInstance/containerGroups"
 	containerLogsURLPath                     = containerGroupURLPath + "/containers/{{.containerName}}/logs"
 	containerExecURLPath                     = containerGroupURLPath + "/containers/{{.containerName}}/exec"
+	containerGroupMetricsURLPath             = containerGroupURLPath + "/providers/microsoft.Insights/metrics"
 )
 
 // Client is a client for interacting with Azure Container Instances.

providers/azure/client/aci/metrics.go

@@ -0,0 +1,97 @@
+package aci
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/url"
+	"path"
+	"time"
+
+	"github.com/pkg/errors"
+	"github.com/virtual-kubelet/virtual-kubelet/providers/azure/client/api"
+)
+
+// GetContainerGroupMetrics gets metrics for the provided container group
+func (c *Client) GetContainerGroupMetrics(ctx context.Context, resourceGroup, containerGroup string, options MetricsRequest) (*ContainerGroupMetricsResult, error) {
+	if len(options.Types) == 0 {
+		return nil, errors.New("must provide metrics types to fetch")
+	}
+	if options.Start.After(options.End) || options.Start.Equal(options.End) && !options.Start.IsZero() {
+		return nil, errors.Errorf("end parameter must be after start: start=%s, end=%s", options.Start, options.End)
+	}
+
+	var metricNames string
+	for _, t := range options.Types {
+		if len(metricNames) > 0 {
+			metricNames += ","
+		}
+		metricNames += string(t)
+	}
+
+	var ag string
+	for _, a := range options.Aggregations {
+		if len(ag) > 0 {
+			ag += ","
+		}
+		ag += string(a)
+	}
+
+	urlParams := url.Values{
+		"api-version": []string{"2018-01-01"},
+		"aggregation": []string{ag},
+		"metricnames": []string{metricNames},
+		"interval":    []string{"PT1M"}, // TODO: make configurable?
+	}
+
+	if options.Dimension != "" {
+		urlParams.Add("$filter", options.Dimension)
+	}
+
+	if !options.Start.IsZero() || !options.End.IsZero() {
+		urlParams.Add("timespan", path.Join(options.Start.Format(time.RFC3339), options.End.Format(time.RFC3339)))
+	}
+
+	// Create the url.
+	uri := api.ResolveRelative(c.auth.ResourceManagerEndpoint, containerGroupMetricsURLPath)
+	uri += "?" + url.Values(urlParams).Encode()
+
+	// Create the request.
+	req, err := http.NewRequest("GET", uri, nil)
+	if err != nil {
+		return nil, errors.Wrap(err, "creating get container group metrics uri request failed")
+	}
+	req = req.WithContext(ctx)
+
+	// Add the parameters to the url.
+	if err := api.ExpandURL(req.URL, map[string]string{
+		"subscriptionId":     c.auth.SubscriptionID,
+		"resourceGroup":      resourceGroup,
+		"containerGroupName": containerGroup,
+	}); err != nil {
+		return nil, errors.Wrap(err, "expanding URL with parameters failed")
+	}
+
+	// SEnd the request.
+	resp, err := c.hc.Do(req)
+	if err != nil {
+		return nil, errors.Wrap(err, "sending get container group metrics request failed")
+	}
+	defer resp.Body.Close()
+
+	// 200 (OK) is a success response.
+	if err := api.CheckResponse(resp); err != nil {
+		return nil, err
+	}
+
+	// Decode the body from the response.
+	if resp.Body == nil {
+		return nil, errors.New("container group metrics returned an empty body in the response")
+	}
+	var metrics ContainerGroupMetricsResult
+	if err := json.NewDecoder(resp.Body).Decode(&metrics); err != nil {
+		return nil, errors.Wrap(err, "decoding get container group metrics response body failed")
+	}
+
+	return &metrics, nil
+}

providers/azure/client/aci/types.go

@@ -1,6 +1,8 @@
 package aci
 
 import (
+	"time"
+
 	"github.com/virtual-kubelet/virtual-kubelet/providers/azure/client/api"
 )
 
@@ -332,3 +334,85 @@ type LogAnalyticsWorkspace struct {
 	WorkspaceID  string `json:"workspaceID,omitempty"`
 	WorkspaceKey string `json:"workspaceKey,omitempty"`
 }
+
+// ContainerGroupMetricsResult stores all the results for a container group metrics request.
+type ContainerGroupMetricsResult struct {
+	Value []MetricValue `json:"value"`
+}
+
+// MetricValue stores metrics results
+type MetricValue struct {
+	ID         string             `json:"id"`
+	Desc       MetricDescriptor   `json:"name"`
+	Timeseries []MetricTimeSeries `json:"timeseries"`
+	Type       string             `json:"type"`
+	Unit       string             `json:"unit"`
+}
+
+// MetricDescriptor stores the name for a given metric and the localized version of that name.
+type MetricDescriptor struct {
+	Value          MetricType `json:"value"`
+	LocalizedValue string     `json:"localizedValue"`
+}
+
+// MetricTimeSeries is the time series for a given metric
+// It contains all the metrics values and other details for the dimension the metrics are aggregated on.
+type MetricTimeSeries struct {
+	Data           []TimeSeriesEntry     `json:"data"`
+	MetadataValues []MetricMetadataValue `json:"metadatavalues,omitempty"`
+}
+
+// MetricMetadataValue stores extra metadata about a metric
+// In particular it is used to provide details about the breakdown of a metric dimension.
+type MetricMetadataValue struct {
+	Name  ValueDescriptor `json:"name"`
+	Value string          `json:"value"`
+}
+
+// ValueDescriptor describes a generic value.
+// It is used to describe metadata fields.
+type ValueDescriptor struct {
+	Value          string `json:"value"`
+	LocalizedValue string `json:"localizedValue"`
+}
+
+// TimeSeriesEntry is the metric data for a given timestamp/metric type
+type TimeSeriesEntry struct {
+	Timestamp time.Time `json:"timestamp"`
+	Average   float64   `json:"average"`
+	Total     float64   `json:"total"`
+	Count     float64   `json:"count"`
+}
+
+// MetricsRequest is an options struct used when getting container group metrics
+type MetricsRequest struct {
+	Start        time.Time
+	End          time.Time
+	Types        []MetricType
+	Aggregations []AggregationType
+
+	// Note that a dimension may not be available for certain metrics.
+	// In such cases, you will need to make separate requests.
+	Dimension string
+}
+
+// MetricType is an enum type for defining supported metric types.
+type MetricType string
+
+// Supported metric types
+const (
+	MetricTypeCPUUsage                          MetricType = "CpuUsage"
+	MetricTypeMemoryUsage                       MetricType = "MemoryUsage"
+	MetricTyperNetworkBytesRecievedPerSecond    MetricType = "NetworkBytesReceivedPerSecond"
+	MetricTyperNetworkBytesTransmittedPerSecond MetricType = "NetworkBytesTransmittedPerSecond"
+)
+
+// AggregationType is an enum type for defining supported aggregation types
+type AggregationType string
+
+// Supported metric aggregation types
+const (
+	AggregationTypeCount   AggregationType = "count"
+	AggregationTypeAverage AggregationType = "average"
+	AggregationTypeTotal   AggregationType = "total"
+)