Adds LoadAvg info in /status

Author: grussorusso

docs/api.md

@@ -156,8 +156,68 @@ An example response for a successful **asynchronous** request:
 > | `503`         | `text/plain`              |  |    Prewarming failed                        |
 
 ------------------------------------------------------------------------------------------
+### Status information
 
-<!--
-status API
-function API
--->
+ <code>GET</code> <code><b>/status</b></code> (get current status of the node)
+
+##### Parameters
+
+None
+
+##### Responses
+
+> | http code     | content-type                      | response                        | comments                                    |
+> |---------------|-----------------------------------|---------------------------------|-----------------------------------|
+> | `200`         | `application/json`        | *See response example.*    |                            |
+> | `500`         | `text/plain`              | `Could not retrieve results` |    
+
+An example response for a successful request:
+
+```
+{
+	"Url": "http://192.168.1.23:1323",
+	"AvailableWarmContainers": {
+		"isprime": 1,
+		"sleepSec": 2
+	},
+	"AvailableMemMB": 3072,
+	"AvailableCPUs": 8,
+	"Coordinates": {
+		"Vec": [
+			0,
+			0,
+			0
+		],
+		"Error": 1.5,
+		"Height": 0.00001
+	},
+	"LoadAvg": [
+		1.34,
+		1.43,
+		0.94
+	]
+}
+```
+
+`AvailableMemMB` and `AvailableCPUs` indicate the currently amount of memory
+and CPUs (intended as vCPUs or fractions of them) that can be allocated to new
+requests in the node. `Coordinates.Vec` reports the coordinates of this node
+in the virtual coordinate space computed by Vivaldi algorithm.
+
+### Listing functions
+
+ <code>GET</code> <code><b>/functions</b></code> (get list of registered functions)
+
+##### Parameters
+
+None
+
+##### Responses
+
+> | http code     | content-type                      | response                        | comments                                    |
+> |---------------|-----------------------------------|---------------------------------|-----------------------------------|
+> | `200`         | `application/json`        | *List of names of existing functions.*    |                            |
+> | `500`         | `text/plain`              | `Could not retrieve results` |    
+
+Note that functions are globally registered in the system. Therefore, the same
+list is returned by every node in the same cluster.

go.mod

@@ -10,13 +10,15 @@ require (
 	github.com/hexablock/vivaldi v0.0.0-20180727225019-07adad3f2b5f
 	github.com/labstack/echo/v4 v4.6.1
 	github.com/lithammer/shortuuid v3.0.0+incompatible
+	github.com/mikoim/go-loadavg v0.0.0-20150917074714-35ece5f6d547
 	github.com/prometheus/client_golang v1.13.0
 	github.com/spf13/cobra v1.0.0
 	github.com/spf13/viper v1.4.0
 	go.etcd.io/etcd/client/v3 v3.5.1
 	go.opentelemetry.io/otel v1.28.0
 	go.opentelemetry.io/otel/exporters/stdout/stdouttrace v1.28.0
 	go.opentelemetry.io/otel/sdk v1.28.0
+	go.opentelemetry.io/otel/trace v1.28.0
 	golang.org/x/net v0.0.0-20220225172249-27dd8689420f
 )
 
@@ -65,7 +67,6 @@ require (
 	go.etcd.io/etcd/api/v3 v3.5.1 // indirect
 	go.etcd.io/etcd/client/pkg/v3 v3.5.1 // indirect
 	go.opentelemetry.io/otel/metric v1.28.0 // indirect
-	go.opentelemetry.io/otel/trace v1.28.0 // indirect
 	go.uber.org/atomic v1.7.0 // indirect
 	go.uber.org/multierr v1.6.0 // indirect
 	go.uber.org/zap v1.17.0 // indirect

go.sum

@@ -480,6 +480,8 @@ github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5
 github.com/matttproud/golang_protobuf_extensions v1.0.2-0.20181231171920-c182affec369 h1:I0XW9+e1XWDxdcEniV4rQAIOPUGDq67JSCiRCgGCZLI=
 github.com/matttproud/golang_protobuf_extensions v1.0.2-0.20181231171920-c182affec369/go.mod h1:BSXmuO+STAnVfrANrmjBb36TMTDstsz7MSK+HVaYKv4=
 github.com/miekg/pkcs11 v1.0.3/go.mod h1:XsNlhZGX73bx86s2hdc/FuaLm2CPZJemRLMA+WTFxgs=
+github.com/mikoim/go-loadavg v0.0.0-20150917074714-35ece5f6d547 h1:sKOBS3TQA6gIeu7xDDIJnH1cPmGAa3535gg2/cWrwC4=
+github.com/mikoim/go-loadavg v0.0.0-20150917074714-35ece5f6d547/go.mod h1:Gv1gEAo58s56eUbsb59IAFnEr6flyFg9lgryVQnKwhM=
 github.com/mistifyio/go-zfs v2.1.2-0.20190413222219-f784269be439+incompatible/go.mod h1:8AuVvqP/mXw1px98n46wfvcGfQ4ci2FwoAjKYxuo3Z4=
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/mitchellh/mapstructure v1.1.2 h1:fmNYVwqnSfB9mZU6OS2O6GsXM+wcskZDuKQzvN1EDeE=

internal/api/api.go

@@ -21,8 +21,9 @@ import (
 	"github.com/serverledge-faas/serverledge/utils"
 	"go.opentelemetry.io/otel/attribute"
 
-	"github.com/serverledge-faas/serverledge/internal/scheduling"
 	"github.com/labstack/echo/v4"
+	"github.com/mikoim/go-loadavg"
+	"github.com/serverledge-faas/serverledge/internal/scheduling"
 )
 
 var requestsPool = sync.Pool{
@@ -204,14 +205,23 @@ func DecodeServiceClass(serviceClass string) (p function.ServiceClass) {
 func GetServerStatus(c echo.Context) error {
 	node.Resources.RLock()
 	defer node.Resources.RUnlock()
+
 	portNumber := config.GetInt("api.port", 1323)
 	url := fmt.Sprintf("http://%s:%d", utils.GetIpAddress().String(), portNumber)
+
+	loadAvg, err := loadavg.Parse()
+	loadAvgValues := []float64{-1.0, -1.0, -1.0}
+	if err == nil {
+		loadAvgValues = []float64{loadAvg.LoadAverage1, loadAvg.LoadAverage5, loadAvg.LoadAverage10}
+	}
+
 	response := registration.StatusInformation{
-		Url:            url,
-		AvailableMemMB: node.Resources.AvailableMemMB,
-		AvailableCPUs:  node.Resources.AvailableCPUs,
-		DropCount:      node.Resources.DropCount,
-		Coordinates:    *registration.Reg.Client.GetCoordinate(),
+		Url:                     url,
+		AvailableWarmContainers: node.WarmStatus(),
+		AvailableMemMB:          node.Resources.AvailableMemMB,
+		AvailableCPUs:           node.Resources.AvailableCPUs,
+		Coordinates:             *registration.Reg.Client.GetCoordinate(),
+		LoadAvg:                 loadAvgValues,
 	}
 
 	return c.JSON(http.StatusOK, response)

internal/registration/edgeNetUDPDiscovery.go

@@ -66,6 +66,7 @@ func handleUDPConnection(conn *net.UDPConn) {
 	}
 }
 
+// TODO: this function should reuse the code in api.go for the /status API
 func getCurrentStatusInformation() (status []byte, err error) {
 	portNumber := config.GetInt("api.port", 1323)
 	url := fmt.Sprintf("http://%s:%d", utils.GetIpAddress().String(), portNumber)
@@ -74,7 +75,6 @@ func getCurrentStatusInformation() (status []byte, err error) {
 		AvailableWarmContainers: node.WarmStatus(),
 		AvailableMemMB:          node.Resources.AvailableMemMB,
 		AvailableCPUs:           node.Resources.AvailableCPUs,
-		DropCount:               node.Resources.DropCount,
 		Coordinates:             *Reg.Client.GetCoordinate(),
 	}
 

internal/registration/types.go

@@ -26,6 +26,6 @@ type StatusInformation struct {
 	AvailableWarmContainers map[string]int // <k, v> = <function name, warm container number>
 	AvailableMemMB          int64
 	AvailableCPUs           float64
-	DropCount               int64
 	Coordinates             vivaldi.Coordinate
+	LoadAvg                 []float64
 }