server/config: Add test configuration package.

luci_config/server/cfgclient/backend/testconfig/local_service.go

Index: luci_config/server/cfgclient/backend/testconfig/local_service.go
diff --git a/luci_config/server/cfgclient/backend/testconfig/local_service.go b/luci_config/server/cfgclient/backend/testconfig/local_service.go
new file mode 100644
index 0000000000000000000000000000000000000000..97e04b008e6b6a4fdeeee783eb784cf119910ed7
--- /dev/null
+++ b/luci_config/server/cfgclient/backend/testconfig/local_service.go
@@ -0,0 +1,105 @@
+// Copyright 2016 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 testconfig
+
+import (
+	"net/url"
+
+	ccfg "github.com/luci/luci-go/common/config"
+	"github.com/luci/luci-go/luci_config/common/cfgtypes"
+	"github.com/luci/luci-go/luci_config/server/cfgclient"
+	"github.com/luci/luci-go/luci_config/server/cfgclient/access"
+	"github.com/luci/luci-go/luci_config/server/cfgclient/backend"
+	"github.com/luci/luci-go/luci_config/server/cfgclient/backend/client"
+
+	"golang.org/x/net/context"
+)
+
+// WithCommonClient installs a backend.B into the supplied Context that
+// loads its configuration from base.
+func WithCommonClient(c context.Context, base ccfg.Interface) context.Context {
+	return backend.WithBackend(c, &client.Backend{
+		Provider: &Provider{
+			Base: base,
+		},
+	})
+}
+
+// Provider is a client.Provider that is backed by a config interface.
+// This differs from client.RemoteProvider in that it takes an arbitrary
+// config interface instance rather than generating a remote one.
+//
+// Its intended use is for testing setups.
+//
+// Provider performs access checks locally using access.CheckAccess.
+type Provider struct {
+	// Base is the base interface.
+	Base ccfg.Interface
+}
+
+var _ client.Provider = (*Provider)(nil)
+
+// GetConfigClient implements ClientProvider.
+func (p *Provider) GetConfigClient(c context.Context, a backend.Authority) ccfg.Interface {
+	return &boundLocalInterface{
+		Context:   c,
+		Interface: p.Base,
+		lsp:       p,
+		a:         a,
+	}
+}
+
+// boundLocalInterface is a ccfg.Interface implementation that adds ACL
+// pruning to the results based on the bound authority.
+type boundLocalInterface struct {
+	context.Context
+
+	// Interface is the config interface implementation.
+	ccfg.Interface
+
+	lsp *Provider
+	a   backend.Authority
+}
+
+func (bli *boundLocalInterface) GetConfig(ctx context.Context, configSet, path string, hashOnly bool) (*ccfg.Config, error) {
+	if err := access.Check(bli, bli.a, cfgtypes.ConfigSet(configSet)); err != nil {
+		return nil, ccfg.ErrNoConfig
+	}
+	return bli.Interface.GetConfig(ctx, configSet, path, hashOnly)
+}
+
+func (bli *boundLocalInterface) GetProjectConfigs(ctx context.Context, path string, hashesOnly bool) ([]ccfg.Config, error) {
+	cfgs, err := bli.Interface.GetProjectConfigs(ctx, path, hashesOnly)
+	if err != nil {
+		return nil, err
+	}
+	return bli.pruneConfigList(cfgs), nil
+}
+
+func (bli *boundLocalInterface) GetRefConfigs(ctx context.Context, path string, hashesOnly bool) ([]ccfg.Config, error) {
+	cfgs, err := bli.Interface.GetRefConfigs(ctx, path, hashesOnly)
+	if err != nil {
+		return nil, err
+	}
+	return bli.pruneConfigList(cfgs), nil
+}
+
+func (bli *boundLocalInterface) GetConfigSetLocation(ctx context.Context, configSet string) (*url.URL, error) {
+	if err := access.Check(ctx, bli.a, cfgtypes.ConfigSet(configSet)); err != nil {
+		return nil, cfgclient.ErrNoConfig
+	}
+	return bli.Interface.GetConfigSetLocation(ctx, configSet)
+}
+
+func (bli *boundLocalInterface) pruneConfigList(cl []ccfg.Config) []ccfg.Config {
+	ptr := 0
+	for i := range cl {
+		if err := access.Check(bli, bli.a, cfgtypes.ConfigSet(cl[i].ConfigSet)); err == nil {
+			cl[ptr] = cl[i]
+			ptr++
+		}
+	}
+	return cl[:ptr]
+}