Add server/cache support to gaeconfig.

common/config/context.go

Index: common/config/context.go
diff --git a/common/config/context.go b/common/config/context.go
deleted file mode 100644
index 61ade3bed3560c4f7cb79c7e32ad97730170ee2c..0000000000000000000000000000000000000000
--- a/common/config/context.go
+++ /dev/null
@@ -1,148 +0,0 @@
-// 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 config
-
-import (
-	"errors"
-	"net/url"
-
-	"golang.org/x/net/context"
-)
-
-var errNoImpl = errors.New("config: the context doesn't have Interface installed, use SetImplementation")
-
-type contextKey int
-
-// SetImplementation sets the current Interface implementation in the context.
-//
-// By keeping Interface in the context we allow high level libraries to use
-// a config client implementation without explicitly passing it through all
-// method calls.
-//
-// This implementation is also used by package level functions declared below
-// (see GetConfig, etc).
-func SetImplementation(c context.Context, ri Interface) context.Context {
-	return context.WithValue(c, contextKey(0), ri)
-}
-
-// GetImplementation returns the Interface object from context.
-//
-// It should be installed there by 'SetImplementation' already.
-//
-// Returns nil if it's not there.
-func GetImplementation(c context.Context) Interface {
-	ret, _ := c.Value(contextKey(0)).(Interface)
-	return ret
-}
-
-////////////////////////////////////////////////////////////////////////////////
-// Functions below mimic Interface API.
-//
-// They forward calls to an Interface implementation in the context or panic if
-// it isn't installed.
-
-// ServiceURL returns the URL of the config service.
-//
-// The function just forwards the call to corresponding method of Interface
-// implementation installed in the context with SetImplementation.
-func ServiceURL(ctx context.Context) url.URL {
-	impl := GetImplementation(ctx)
-	if impl == nil {
-		panic(errNoImpl)
-	}
-	return impl.ServiceURL(ctx)
-}
-
-// GetConfig returns a config at a path in a config set or ErrNoConfig
-// if missing. If hashOnly is true, returned Config struct has Content set
-// to "" (and the call is faster).
-//
-// The function just forwards the call to corresponding method of Interface
-// implementation installed in the context with SetImplementation.
-func GetConfig(ctx context.Context, configSet, path string, hashOnly bool) (*Config, error) {
-	impl := GetImplementation(ctx)
-	if impl == nil {
-		panic(errNoImpl)
-	}
-	return impl.GetConfig(ctx, configSet, path, hashOnly)
-}
-
-// GetConfigByHash returns the contents of a config, as identified by its
-// content hash, or ErrNoConfig if missing.
-//
-// The function just forwards the call to corresponding method of Interface
-// implementation installed in the context with SetImplementation.
-func GetConfigByHash(ctx context.Context, contentHash string) (string, error) {
-	impl := GetImplementation(ctx)
-	if impl == nil {
-		panic(errNoImpl)
-	}
-	return impl.GetConfigByHash(ctx, contentHash)
-}
-
-// GetConfigSetLocation returns the URL location of a config set.
-//
-// The function just forwards the call to corresponding method of Interface
-// implementation installed in the context with SetImplementation.
-func GetConfigSetLocation(ctx context.Context, configSet string) (*url.URL, error) {
-	impl := GetImplementation(ctx)
-	if impl == nil {
-		panic(errNoImpl)
-	}
-	return impl.GetConfigSetLocation(ctx, configSet)
-}
-
-// GetProjectConfigs returns all the configs at the given path in all
-// projects that have such config. If hashesOnly is true, returned Config
-// structs have Content set to "" (and the call is faster).
-//
-// The function just forwards the call to corresponding method of Interface
-// implementation installed in the context with SetImplementation.
-func GetProjectConfigs(ctx context.Context, path string, hashesOnly bool) ([]Config, error) {
-	impl := GetImplementation(ctx)
-	if impl == nil {
-		panic(errNoImpl)
-	}
-	return impl.GetProjectConfigs(ctx, path, hashesOnly)
-}
-
-// GetProjects returns all the registered projects in the configuration
-// service.
-//
-// The function just forwards the call to corresponding method of Interface
-// implementation installed in the context with SetImplementation.
-func GetProjects(ctx context.Context) ([]Project, error) {
-	impl := GetImplementation(ctx)
-	if impl == nil {
-		panic(errNoImpl)
-	}
-	return impl.GetProjects(ctx)
-}
-
-// GetRefConfigs returns the config at the given path in all refs of all
-// projects that have such config. If hashesOnly is true, returned Config
-// structs have Content set to "" (and the call is faster).
-//
-// The function just forwards the call to corresponding method of Interface
-// implementation installed in the context with SetImplementation.
-func GetRefConfigs(ctx context.Context, path string, hashesOnly bool) ([]Config, error) {
-	impl := GetImplementation(ctx)
-	if impl == nil {
-		panic(errNoImpl)
-	}
-	return impl.GetRefConfigs(ctx, path, hashesOnly)
-}
-
-// GetRefs returns the list of refs for a project.
-//
-// The function just forwards the call to corresponding method of Interface
-// implementation installed in the context with SetImplementation.
-func GetRefs(ctx context.Context, projectID string) ([]string, error) {
-	impl := GetImplementation(ctx)
-	if impl == nil {
-		panic(errNoImpl)
-	}
-	return impl.GetRefs(ctx, projectID)
-}