Unify addons and agent packages

README.md

@@ -23,8 +23,8 @@
 is a network protocol for remote management of large fleets of data collection Agents.
 
 OpAMP allows Agents to report their status to and receive configuration from a
-Server and to receive addons and agent installation package updates from the
-server. The protocol is vendor-agnostic, so the Server can remotely monitor and
+Server and to receive agent package updates from the server.
+The protocol is vendor-agnostic, so the Server can remotely monitor and
 manage a fleet of different Agents that implement OpAMP, including a fleet of
 mixed agents from different vendors.
 

client/client.go

@@ -45,9 +45,9 @@ type StartSettings struct {
 
 	LastConnectionSettingsHash []byte
 
-	// The hash of the last locally-saved server-provided addons. If nil is passed
-	// it will force the server to send addons list back.
-	LastServerProvidedAllAddonsHash []byte
+	// The hash of the last locally-saved server-provided packages. If nil is passed
+	// it will force the server to send packages list back.
+	LastServerProvidedAllPackagesHash []byte
 }
 
 type OpAMPClient interface {

client/httpclient.go

@@ -92,10 +92,10 @@ func (w *httpClient) Start(settings StartSettings) error {
 				msg.StatusReport = &protobufs.StatusReport{}
 			}
 			msg.StatusReport.AgentDescription = w.settings.AgentDescription
-			if msg.AddonStatuses == nil {
-				msg.AddonStatuses = &protobufs.AgentAddonStatuses{}
+			if msg.PackageStatuses == nil {
+				msg.PackageStatuses = &protobufs.PackageStatuses{}
 			}
-			msg.AddonStatuses.ServerProvidedAllAddonsHash = w.settings.LastServerProvidedAllAddonsHash
+			msg.PackageStatuses.ServerProvidedAllPackagesHash = w.settings.LastServerProvidedAllPackagesHash
 		},
 	)
 	w.looper.ScheduleSend()

client/internal/receivedprocessor.go

@@ -44,7 +44,7 @@ func (r *receivedProcessor) ProcessReceivedMessage(ctx context.Context, msg *pro
 		reportStatus := r.rcvRemoteConfig(ctx, msg.RemoteConfig, msg.Flags)
 
 		r.rcvConnectionSettings(ctx, msg.ConnectionSettings)
-		r.rcvAddonsAvailable(msg.AddonsAvailable)
+		r.rcvPackagesAvailable(msg.PackagesAvailable)
 		r.rcvAgentIdentification(ctx, msg.AgentIdentification)
 
 		if reportStatus {
@@ -154,7 +154,7 @@ func (r *receivedProcessor) processErrorResponse(body *protobufs.ServerErrorResp
 	r.logger.Errorf("received an error from server: %s", body.ErrorMessage)
 }
 
-func (r *receivedProcessor) rcvAddonsAvailable(addons *protobufs.AddonsAvailable) {
+func (r *receivedProcessor) rcvPackagesAvailable(packages *protobufs.PackagesAvailable) {
 	// TODO: implement this.
 }
 

client/types/callbacks.go

@@ -118,16 +118,11 @@ type Callbacks interface {
 		certificate *protobufs.ConnectionSettings,
 	) error
 
-	// OnAddonsAvailable is called when the server has addons available which are
+	// OnPackagesAvailable is called when the server has packages available which are
 	// different from what the agent indicated it has via
-	// LastServerProvidedAllAddonsHash.
-	// syncer can be used to initiate syncing the addons from the server.
-	OnAddonsAvailable(ctx context.Context, addons *protobufs.AddonsAvailable, syncer AddonSyncer) error
-
-	// OnAgentPackageAvailable is called when the server has an agent package available
-	// for the agent.
-	// syncer can be used to initiate syncing the package from the server.
-	OnAgentPackageAvailable(addons *protobufs.AgentPackageAvailable, syncer AgentPackageSyncer) error
+	// LastServerProvidedAllPackagesHash.
+	// syncer can be used to initiate syncing the packages from the server.
+	OnPackagesAvailable(ctx context.Context, packages *protobufs.PackagesAvailable, syncer PackagesSyncer) error
 
 	// OnAgentIdentification is called when the server requests changing identification of the agent.
 	// Agent should be updated with new id and use it for all further communication.
@@ -172,9 +167,8 @@ type CallbacksStruct struct {
 		settings *protobufs.ConnectionSettings,
 	) error
 
-	OnAddonsAvailableFunc       func(ctx context.Context, addons *protobufs.AddonsAvailable, syncer AddonSyncer) error
-	OnAgentPackageAvailableFunc func(addons *protobufs.AgentPackageAvailable, syncer AgentPackageSyncer) error
-	OnAgentIdentificationFunc   func(ctx context.Context, agentId *protobufs.AgentIdentification) error
+	OnPackagesAvailableFunc   func(ctx context.Context, packages *protobufs.PackagesAvailable, syncer PackagesSyncer) error
+	OnAgentIdentificationFunc func(ctx context.Context, agentId *protobufs.AgentIdentification) error
 
 	OnCommandFunc func(command *protobufs.ServerToAgentCommand) error
 }
@@ -243,22 +237,13 @@ func (c CallbacksStruct) OnOtherConnectionSettings(
 	return nil
 }
 
-func (c CallbacksStruct) OnAddonsAvailable(
+func (c CallbacksStruct) OnPackagesAvailable(
 	ctx context.Context,
-	addons *protobufs.AddonsAvailable,
-	syncer AddonSyncer,
-) error {
-	if c.OnAddonsAvailableFunc != nil {
-		return c.OnAddonsAvailableFunc(ctx, addons, syncer)
-	}
-	return nil
-}
-
-func (c CallbacksStruct) OnAgentPackageAvailable(
-	addons *protobufs.AgentPackageAvailable, syncer AgentPackageSyncer,
+	packages *protobufs.PackagesAvailable,
+	syncer PackagesSyncer,
 ) error {
-	if c.OnAgentPackageAvailableFunc != nil {
-		return c.OnAgentPackageAvailableFunc(addons, syncer)
+	if c.OnPackagesAvailableFunc != nil {
+		return c.OnPackagesAvailableFunc(ctx, packages, syncer)
 	}
 	return nil
 }

client/types/packagessyncer.go

@@ -0,0 +1,56 @@
+package types
+
+import (
+	"context"
+	"io"
+)
+
+// PackagesSyncer can be used by the agent to initiate syncing a package from the server.
+// The PackagesSyncer instance knows the right context: the particular OpAMPClient and
+// the particular PackageAvailable message the OnPackageAvailable callback was called for.
+type PackagesSyncer interface {
+	// Sync the available package from the server to the agent.
+	// The agent must supply an PackagesStateProvider to let the Sync function
+	// know what is available locally, what data needs to be sync and how the
+	// data can be stored locally.
+	Sync(ctx context.Context, localState PackagesStateProvider) error
+}
+
+type PackagesStateProvider interface {
+	AllPackagesHash() ([]byte, error)
+
+	// Packages returns the names of all packages that exist in the agent's local storage.
+	Packages() ([]string, error)
+
+	// PackageHash returns the hash of a local package. packageName is one of the names
+	// that were returned by Packages().
+	PackageHash(packageName string) ([]byte, error)
+
+	// CreatePackage creates the package locally. If the package existed must return an error.
+	// If the package did not exist its hash should be set to nil.
+	CreatePackage(packageName string) error
+
+	// FileContentHash returns the content hash of the package file that exists locally.
+	FileContentHash(packageName string) ([]byte, error)
+
+	// UpdateContent must create or update the package content file. The entire content
+	// of the file must be replaced by the data. The data must be read until
+	// it returns an EOF. If reading from data fails UpdateContent must abort and return
+	// an error.
+	// Content hash must be updated if the data is updated without failure.
+	// The function must cancel and return an error if the context is cancelled.
+	UpdateContent(ctx context.Context, packageName string, data io.Reader, contentHash []byte) error
+
+	// SetPackageHash must remember the hash for the specified package. Must be returned
+	// later when PackageHash is called. SetPackageHash is called after UpdateContent
+	// call completes successfully.
+	SetPackageHash(packageName string, hash []byte) error
+
+	// DeletePackage deletes the package from the agent's local storage.
+	DeletePackage(packageName string) error
+
+	// SetAllPackagesHash must remember the AllPackagesHash. Must be returned
+	// later when AllPackagesHash is called. SetAllPackagesHash is called after all
+	// package updates complete successfully.
+	SetAllPackagesHash(hash []byte) error
+}

client/wsclient.go

@@ -292,10 +292,10 @@ func (w *wsClient) runOneCycle(ctx context.Context) {
 
 	w.sender.NextMessage().Update(
 		func(msg *protobufs.AgentToServer) {
-			if msg.AddonStatuses == nil {
-				msg.AddonStatuses = &protobufs.AgentAddonStatuses{}
+			if msg.PackageStatuses == nil {
+				msg.PackageStatuses = &protobufs.PackageStatuses{}
 			}
-			msg.AddonStatuses.ServerProvidedAllAddonsHash = w.settings.LastServerProvidedAllAddonsHash
+			msg.PackageStatuses.ServerProvidedAllPackagesHash = w.settings.LastServerProvidedAllPackagesHash
 		},
 	)