Add memory limit support

Memory limits now work and a function will be killed with OOM
however, it will remain in a stopped state and will not
restart automatically.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

README.md

@@ -148,6 +148,21 @@ You could also perform this task over SSH, or use a configuration management too
 
 > Note: if you are using Caddy or Let's Encrypt for free SSL certificates, that you may hit rate-limits for generating new certificates if you do this too often within a given week.
 
+### Memory limits for functions
+
+Memory limits for functions are supported. When the limit is exceeded the function will be killed.
+
+Example:
+
+```yaml
+functions:
+  figlet:
+    skip_build: true
+    image: functions/figlet:latest
+    limits:
+      memory: 20Mi
+```
+
 ## What does faasd deploy?
 
 * faasd - itself, and its [faas-provider](https://github.com/openfaas/faas-provider) for containerd - CRUD for functions and services, implements the OpenFaaS REST API

pkg/provider/handlers/deploy.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/cio"
+	"github.com/containerd/containerd/containers"
 	"github.com/containerd/containerd/namespaces"
 	"github.com/containerd/containerd/oci"
 	gocni "github.com/containerd/go-cni"
@@ -22,6 +23,7 @@ import (
 	cninetwork "github.com/openfaas/faasd/pkg/cninetwork"
 	"github.com/openfaas/faasd/pkg/service"
 	"github.com/pkg/errors"
+	"k8s.io/apimachinery/pkg/api/resource"
 )
 
 func MakeDeployHandler(client *containerd.Client, cni gocni.CNI, secretMountPath string, alwaysPull bool) func(w http.ResponseWriter, r *http.Request) {
@@ -104,6 +106,18 @@ func deploy(ctx context.Context, req types.FunctionDeployment, client *container
 		labels = *req.Labels
 	}
 
+	var memory *specs.LinuxMemory
+	if req.Limits != nil && len(req.Limits.Memory) > 0 {
+		memory = &specs.LinuxMemory{}
+
+		qty, err := resource.ParseQuantity(req.Limits.Memory)
+		if err != nil {
+			log.Printf("error parsing (%q) as quantity: %s", req.Limits.Memory, err.Error())
+		}
+		v := qty.Value()
+		memory.Limit = &v
+	}
+
 	container, err := client.NewContainer(
 		ctx,
 		name,
@@ -113,7 +127,8 @@ func deploy(ctx context.Context, req types.FunctionDeployment, client *container
 		containerd.WithNewSpec(oci.WithImageConfig(image),
 			oci.WithCapabilities([]string{"CAP_NET_RAW"}),
 			oci.WithMounts(mounts),
-			oci.WithEnv(envs)),
+			oci.WithEnv(envs),
+			withMemory(memory)),
 		containerd.WithContainerLabels(labels),
 	)
 
@@ -210,3 +225,21 @@ func validateSecrets(secretMountPath string, secrets []string) error {
 	}
 	return nil
 }
+
+func withMemory(mem *specs.LinuxMemory) oci.SpecOpts {
+	return func(ctx context.Context, _ oci.Client, c *containers.Container, s *oci.Spec) error {
+		if mem != nil {
+			if s.Linux == nil {
+				s.Linux = &specs.Linux{}
+			}
+			if s.Linux.Resources == nil {
+				s.Linux.Resources = &specs.LinuxResources{}
+			}
+			if s.Linux.Resources.Memory == nil {
+				s.Linux.Resources.Memory = &specs.LinuxMemory{}
+			}
+			s.Linux.Resources.Memory.Limit = mem.Limit
+		}
+		return nil
+	}
+}