create cache proxy based on cache server

act/cacheproxy/model.go

@@ -0,0 +1,44 @@
+package cacheproxy
+
+import (
+	"crypto/sha256"
+	"fmt"
+)
+
+type Request struct {
+	Key     string `json:"key" `
+	Version string `json:"version"`
+	Size    int64  `json:"cacheSize"`
+}
+
+func (c *Request) ToCache() *Cache {
+	if c == nil {
+		return nil
+	}
+	ret := &Cache{
+		Key:     c.Key,
+		Version: c.Version,
+		Size:    c.Size,
+	}
+	if c.Size == 0 {
+		// So the request comes from old versions of actions, like `actions/cache@v2`.
+		// It doesn't send cache size. Set it to -1 to indicate that.
+		ret.Size = -1
+	}
+	return ret
+}
+
+type Cache struct {
+	ID             uint64 `json:"id" boltholdKey:"ID"`
+	Key            string `json:"key" boltholdIndex:"Key"`
+	Version        string `json:"version" boltholdIndex:"Version"`
+	KeyVersionHash string `json:"keyVersionHash" boltholdUnique:"KeyVersionHash"`
+	Size           int64  `json:"cacheSize"`
+	Complete       bool   `json:"complete"`
+	UsedAt         int64  `json:"usedAt" boltholdIndex:"UsedAt"`
+	CreatedAt      int64  `json:"createdAt" boltholdIndex:"CreatedAt"`
+}
+
+func (c *Cache) FillKeyVersionHash() {
+	c.KeyVersionHash = fmt.Sprintf("%x", sha256.Sum256([]byte(fmt.Sprintf("%s:%s", c.Key, c.Version))))
+}