agent: initialize the cache and cache the CA roots

agent/agent.go

@@ -21,6 +21,8 @@ import (
 	"github.com/armon/go-metrics"
 	"github.com/hashicorp/consul/acl"
 	"github.com/hashicorp/consul/agent/ae"
+	"github.com/hashicorp/consul/agent/cache"
+	"github.com/hashicorp/consul/agent/cache-types"
 	"github.com/hashicorp/consul/agent/checks"
 	"github.com/hashicorp/consul/agent/config"
 	"github.com/hashicorp/consul/agent/consul"
@@ -118,6 +120,9 @@ type Agent struct {
 	// and the remote state.
 	sync *ae.StateSyncer
 
+	// cache is the in-memory cache for data the Agent requests.
+	cache *cache.Cache
+
 	// checkReapAfter maps the check ID to a timeout after which we should
 	// reap its associated service
 	checkReapAfter map[types.CheckID]time.Duration
@@ -290,6 +295,9 @@ func (a *Agent) Start() error {
 	// regular and on-demand state synchronizations (anti-entropy).
 	a.sync = ae.NewStateSyncer(a.State, c.AEInterval, a.shutdownCh, a.logger)
 
+	// create the cache
+	a.cache = cache.New(nil)
+
 	// create the config for the rpc server/client
 	consulCfg, err := a.consulConfig()
 	if err != nil {
@@ -326,6 +334,9 @@ func (a *Agent) Start() error {
 	a.State.Delegate = a.delegate
 	a.State.TriggerSyncChanges = a.sync.SyncChanges.Trigger
 
+	// Register the cache
+	a.registerCache()
+
 	// Load checks/services/metadata.
 	if err := a.loadServices(c); err != nil {
 		return err
@@ -2624,3 +2635,18 @@ func (a *Agent) ReloadConfig(newCfg *config.RuntimeConfig) error {
 
 	return nil
 }
+
+// registerCache configures the cache and registers all the supported
+// types onto the cache. This is NOT safe to call multiple times so
+// care should be taken to call this exactly once after the cache
+// field has been initialized.
+func (a *Agent) registerCache() {
+	a.cache.RegisterType(cachetype.ConnectCARootName, &cachetype.ConnectCARoot{
+		RPC: a.delegate,
+	}, &cache.RegisterOptions{
+		// Maintain a blocking query, retry dropped connections quickly
+		Refresh:        true,
+		RefreshTimer:   0,
+		RefreshTimeout: 10 * time.Minute,
+	})
+}

agent/agent_endpoint.go

@@ -13,6 +13,7 @@ import (
 	"github.com/mitchellh/hashstructure"
 
 	"github.com/hashicorp/consul/acl"
+	"github.com/hashicorp/consul/agent/cache-types"
 	"github.com/hashicorp/consul/agent/checks"
 	"github.com/hashicorp/consul/agent/config"
 	"github.com/hashicorp/consul/agent/connect"
@@ -885,10 +886,24 @@ func (s *HTTPServer) AgentToken(resp http.ResponseWriter, req *http.Request) (in
 
 // AgentConnectCARoots returns the trusted CA roots.
 func (s *HTTPServer) AgentConnectCARoots(resp http.ResponseWriter, req *http.Request) (interface{}, error) {
-	// NOTE(mitchellh): for now this is identical to /v1/connect/ca/roots.
-	// In the future, we're going to do some agent-local caching and the
-	// behavior will differ.
-	return s.ConnectCARoots(resp, req)
+	var args structs.DCSpecificRequest
+	if done := s.parse(resp, req, &args.Datacenter, &args.QueryOptions); done {
+		return nil, nil
+	}
+
+	raw, err := s.agent.cache.Get(cachetype.ConnectCARootName, &args)
+	if err != nil {
+		return nil, err
+	}
+
+	reply, ok := raw.(*structs.IndexedCARoots)
+	if !ok {
+		// This should never happen, but we want to protect against panics
+		return nil, fmt.Errorf("internal error: response type not correct")
+	}
+	defer setMeta(resp, &reply.QueryMeta)
+
+	return *reply, nil
 }
 
 // AgentConnectCALeafCert returns the certificate bundle for a service

agent/cache-types/connect_ca.go

@@ -7,12 +7,15 @@ import (
 	"github.com/hashicorp/consul/agent/structs"
 )
 
-// TypeCARoot supports fetching the Connect CA roots.
-type TypeCARoot struct {
+// Recommended name for registration for ConnectCARoot
+const ConnectCARootName = "connect-ca"
+
+// ConnectCARoot supports fetching the Connect CA roots.
+type ConnectCARoot struct {
 	RPC RPC
 }
 
-func (c *TypeCARoot) Fetch(opts cache.FetchOptions, req cache.Request) (cache.FetchResult, error) {
+func (c *ConnectCARoot) Fetch(opts cache.FetchOptions, req cache.Request) (cache.FetchResult, error) {
 	var result cache.FetchResult
 
 	// The request should be a DCSpecificRequest.

agent/cache-types/connect_ca_test.go

@@ -10,11 +10,11 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestTypeCARoot(t *testing.T) {
+func TestConnectCARoot(t *testing.T) {
 	require := require.New(t)
 	rpc := TestRPC(t)
 	defer rpc.AssertExpectations(t)
-	typ := &TypeCARoot{RPC: rpc}
+	typ := &ConnectCARoot{RPC: rpc}
 
 	// Expect the proper RPC call. This also sets the expected value
 	// since that is return-by-pointer in the arguments.
@@ -42,11 +42,11 @@ func TestTypeCARoot(t *testing.T) {
 	}, result)
 }
 
-func TestTypeCARoot_badReqType(t *testing.T) {
+func TestConnectCARoot_badReqType(t *testing.T) {
 	require := require.New(t)
 	rpc := TestRPC(t)
 	defer rpc.AssertExpectations(t)
-	typ := &TypeCARoot{RPC: rpc}
+	typ := &ConnectCARoot{RPC: rpc}
 
 	// Fetch
 	_, err := typ.Fetch(cache.FetchOptions{}, cache.TestRequest(