worker: add memory endpoint

api/worker.go

@@ -51,6 +51,15 @@ type (
 		Error     string     `json:"error,omitempty"`
 	}
 
+	MemoryResponse struct {
+		Upload MemoryStatus `json:"upload"`
+	}
+
+	MemoryStatus struct {
+		Available uint64 `json:"available"`
+		Total     uint64 `json:"total"`
+	}
+
 	// MigrateSlabResponse is the response type for the /slab/migrate endpoint.
 	MigrateSlabResponse struct {
 		NumShardsMigrated int    `json:"numShardsMigrated"`

worker/client/client.go

@@ -136,6 +136,12 @@ func (c *Client) ID(ctx context.Context) (id string, err error) {
 	return
 }
 
+// Memory requests the /memory endpoint.
+func (c *Client) Memory(ctx context.Context) (resp api.MemoryResponse, err error) {
+	err = c.c.WithContext(ctx).GET("/memory", &resp)
+	return
+}
+
 // MigrateSlab migrates the specified slab.
 func (c *Client) MigrateSlab(ctx context.Context, slab object.Slab, set string) (res api.MigrateSlabResponse, err error) {
 	values := make(url.Values)

worker/memory.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"fmt"
 	"sync"
+
+	"go.sia.tech/renterd/api"
 )
 
 type (
@@ -37,6 +39,15 @@ func newMemoryManager(maxMemory uint64) (*memoryManager, error) {
 	return mm, nil
 }
 
+func (mm *memoryManager) Status() api.MemoryStatus {
+	mm.mu.Lock()
+	defer mm.mu.Unlock()
+	return api.MemoryStatus{
+		Available: mm.available,
+		Total:     mm.totalAvailable,
+	}
+}
+
 func (mm *memoryManager) AcquireMemory(ctx context.Context, amt uint64) <-chan *acquiredMemory {
 	if amt == 0 {
 		panic("cannot acquire 0 memory")

worker/worker.go

@@ -1340,6 +1340,12 @@ func (w *worker) idHandlerGET(jc jape.Context) {
 	jc.Encode(w.id)
 }
 
+func (w *worker) memoryGET(jc jape.Context) {
+	jc.Encode(api.MemoryResponse{
+		Upload: w.uploadManager.mm.Status(),
+	})
+}
+
 func (w *worker) accountHandlerGET(jc jape.Context) {
 	var hostKey types.PublicKey
 	if jc.DecodeParam("hostkey", &hostKey) != nil {
@@ -1409,6 +1415,8 @@ func (w *worker) Handler() http.Handler {
 		"GET    /account/:hostkey": w.accountHandlerGET,
 		"GET    /id":               w.idHandlerGET,
 
+		"GET /memory": w.memoryGET,
+
 		"GET    /rhp/contracts":              w.rhpContractsHandlerGET,
 		"POST   /rhp/contract/:id/broadcast": w.rhpBroadcastHandler,
 		"POST   /rhp/contract/:id/prune":     w.rhpPruneContractHandlerPOST,