Implement package cache API

distro/debian/cache.go

@@ -0,0 +1,30 @@
+package debian
+
+import (
+	"github.com/rapidloop/skv"
+
+	"code.dumpstack.io/tools/out-of-tree/distro/debian/snapshot"
+)
+
+type Cache struct {
+	store *skv.KVStore
+}
+
+func NewCache(path string) (c *Cache, err error) {
+	c = &Cache{}
+	c.store, err = skv.Open(path)
+	return
+}
+
+func (c Cache) Put(p snapshot.Package) error {
+	return c.store.Put(p.Version, p)
+}
+
+func (c Cache) Get(version string) (p snapshot.Package, err error) {
+	err = c.store.Get(version, &p)
+	return
+}
+
+func (c Cache) Close() error {
+	return c.store.Close()
+}

distro/debian/cache_test.go

@@ -0,0 +1,68 @@
+package debian
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/rapidloop/skv"
+
+	"code.dumpstack.io/tools/out-of-tree/distro/debian/snapshot"
+)
+
+func TestCache(t *testing.T) {
+	dir, err := os.MkdirTemp("", "out-of-tree_cache_test_")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(dir)
+
+	path := filepath.Join(dir, "debian.cache")
+
+	c, err := NewCache(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	packages, err := snapshot.Packages("linux", "4.17.14-1", "amd64",
+		`^linux-(image|headers)-[0-9\.\-]*-(amd64|amd64-unsigned)$`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = c.Put(packages[0])
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	p, err := c.Get(packages[0].Version)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if p.Deb.Hash != packages[0].Deb.Hash {
+		t.Fatalf("mismatch")
+	}
+
+	c.Close()
+
+	c, err = NewCache(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+
+	p, err = c.Get(packages[0].Version)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if p.Deb.Hash != packages[0].Deb.Hash {
+		t.Fatalf("mismatch")
+	}
+
+	p, err = c.Get("key not exist")
+	if err == nil || err != skv.ErrNotFound {
+		t.Fatal(err)
+	}
+}