Function processSnapshotUpdate

vpn/tunnel.go:673–706

processSnapshotUpdate handles the logic when a full state update is received. When the tunnel is live, we only receive diffs, but the first packet on any given reconnect to the tailnet API is a full state. Without this logic we weren't processing deletes for any workspaces or agents deleted while th

(update *tailnet.WorkspaceUpdate, agents map[uuid.UUID]agentWithPing, workspaces map[uuid.UUID]tailnet.Workspace)

// Without this logic we weren't processing deletes for any workspaces or agents deleted
// while the client was disconnected while the computer was asleep.
func processSnapshotUpdate(update *tailnet.WorkspaceUpdate, agents map[uuid.UUID]agentWithPing, workspaces map[uuid.UUID]tailnet.Workspace) {
	// ignoredWorkspaces is initially populated with the workspaces that are
	// in the current update. Later on we populate it with the deleted workspaces too
	// so that we don't send duplicate updates. Same applies to ignoredAgents.
	ignoredWorkspaces := make(map[uuid.UUID]struct{}, len(update.UpsertedWorkspaces))
	ignoredAgents := make(map[uuid.UUID]struct{}, len(update.UpsertedAgents))

	for _, workspace := range update.UpsertedWorkspaces {
		ignoredWorkspaces[workspace.ID] = struct{}{}
	}
	for _, agent := range update.UpsertedAgents {
		ignoredAgents[agent.ID] = struct{}{}
	}
	for _, agent := range agents {
		if _, present := ignoredAgents[agent.ID]; !present {
			// delete any current agents that are not in the new update
			update.DeletedAgents = append(update.DeletedAgents, &tailnet.Agent{
				ID:          agent.ID,
				Name:        agent.Name,
				WorkspaceID: agent.WorkspaceID,
			})
		}
	}
	for _, workspace := range workspaces {
		if _, present := ignoredWorkspaces[workspace.ID]; !present {
			update.DeletedWorkspaces = append(update.DeletedWorkspaces, &tailnet.Workspace{
				ID:     workspace.ID,
				Name:   workspace.Name,
				Status: workspace.Status,
			})
			ignoredWorkspaces[workspace.ID] = struct{}{}
		}
	}
}

// hostsToIPStrings returns a slice of all unique IP addresses in the values
// of the given map.