server/config: Generic caching backend.

server/config/caching/proccache_test.go

+// Copyright 2015 The LUCI Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
+
+package caching
+
+import (
+        "testing"
+        "time"
+
+        "github.com/luci/luci-go/common/clock/testclock"
+        "github.com/luci/luci-go/common/config/impl/memory"
+        "github.com/luci/luci-go/common/data/caching/proccache"
+        "github.com/luci/luci-go/server/config"
+        "github.com/luci/luci-go/server/config/testconfig"
+
+        "golang.org/x/net/context"
+
+        //. "github.com/luci/luci-go/common/testing/assertions"
+        . "github.com/smartystreets/goconvey/convey"
+)
+
+func TestProcCache(t *testing.T) {
+        t.Parallel()
+
+        Convey(`A testing setup`, t, func() {
+                c := context.Background()
+                c, tc := testclock.UseTime(c, testclock.TestTimeLocal)
+
+                mbase := map[string]memory.ConfigSet{
+                        "projects/foo": {
+                                "file": "content",
+                        },
+                }
+
+                var pc proccache.Cache
+                c = proccache.Use(c, &pc)
+
+                // Install our backend: memory backed by cache backed by force error.
+                var backend config.Backend
+                lcp := testconfig.LocalClientProvider{
+                        Base: memory.New(mbase),
+                }
+                backend = &config.ClientBackend{
+                        Provider: &lcp,
+                }
+                backend = ProcCache(backend, time.Hour)
+                c = config.WithBackend(c, backend)
+
+                Convey(`Will store and cache a value.`, func() {
+                        var s string
+                        So(config.Get(c, config.AsService, "projects/foo", "file", config.String(&s), nil), ShouldBeNil)
+                        So(s, ShouldEqual, "content")
+
+                        delete(mbase, "projects/foo")
+
+                        // Cached.
+                        So(config.Get(c, config.AsService, "projects/foo", "file", config.String(&s), nil), ShouldBeNil)
+                        So(s, ShouldEqual, "content")
+
+                        // Expires, records lack of config.
+                        tc.Add(time.Hour)
+
+                        So(config.Get(c, config.AsService, "projects/foo", "file", config.String(&s), nil),
+                                ShouldEqual, config.ErrNoConfig)
+
+                        // Re-add, still no config.
+                        mbase["projects/foo"] = memory.ConfigSet{
+                                "file": "content",
+                        }
+                        So(config.Get(c, config.AsService, "projects/foo", "file", config.String(&s), nil),
+                                ShouldEqual, config.ErrNoConfig)
+
+                        // "No config" expires, config is back.
+                        tc.Add(time.Hour)
+                        So(config.Get(c, config.AsService, "projects/foo", "file", config.String(&s), nil), ShouldBeNil)
+                        So(s, ShouldEqual, "content")
+                })
+        })
+}