fn: size restricted tmpfs /tmp and read-only / support (#1012)

* fn: size restricted tmpfs /tmp and read-only / support

*) read-only Root Fs Support
*) removed CPUShares from docker API. This was unused.
*) docker.Prepare() refactoring
*) added docker.configureTmpFs() for size limited tmpfs on /tmp
*) tmpfs size support in routes and resource tracker
*) fix fn-test-utils to handle sparse files better in create file

* test typo fix

api/models/call.go

@@ -108,6 +108,9 @@ type Call struct {
 	// Hot function idle timeout in seconds before termination.
 	IdleTimeout int32 `json:"idle_timeout,omitempty" db:"-"`
 
+	// Tmpfs size in megabytes.
+	TmpFsSize uint32 `json:"tmpfs_size,omitempty" db:"-"`
+
 	// Memory is the amount of RAM this call is allocated.
 	Memory uint64 `json:"memory,omitempty" db:"-"`
 

api/models/route.go

@@ -35,6 +35,7 @@ type Route struct {
 	Format      string          `json:"format" db:"format"`
 	Timeout     int32           `json:"timeout" db:"timeout"`
 	IdleTimeout int32           `json:"idle_timeout" db:"idle_timeout"`
+	TmpFsSize   uint32          `json:"tmpfs_size" db:"tmpfs_size"`
 	Config      Config          `json:"config,omitempty" db:"config"`
 	Annotations Annotations     `json:"annotations,omitempty" db:"annotations"`
 	CreatedAt   strfmt.DateTime `json:"created_at,omitempty" db:"created_at"`
@@ -174,6 +175,7 @@ func (r1 *Route) Equals(r2 *Route) bool {
 	eq = eq && r1.Format == r2.Format
 	eq = eq && r1.Timeout == r2.Timeout
 	eq = eq && r1.IdleTimeout == r2.IdleTimeout
+	eq = eq && r1.TmpFsSize == r2.TmpFsSize
 	eq = eq && r1.Config.Equals(r2.Config)
 	eq = eq && r1.Annotations.Equals(r2.Annotations)
 	// NOTE: datastore tests are not very fun to write with timestamp checks,
@@ -207,6 +209,9 @@ func (r *Route) Update(patch *Route) {
 	if patch.IdleTimeout != 0 {
 		r.IdleTimeout = patch.IdleTimeout
 	}
+	if patch.TmpFsSize != 0 {
+		r.TmpFsSize = patch.TmpFsSize
+	}
 	if patch.Format != "" {
 		r.Format = patch.Format
 	}

api/models/route_test.go

@@ -17,6 +17,7 @@ func TestRouteSimple(t *testing.T) {
 		Format:      "http",
 		Timeout:     10,
 		IdleTimeout: 10,
+		TmpFsSize:   10,
 	}
 
 	err := route1.Validate()