Don Newton | 379ae25 | 2019-04-01 12:17:06 -0400 | [diff] [blame^] | 1 | // Copyright (C) MongoDB, Inc. 2017-present. |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); you may |
| 4 | // not use this file except in compliance with the License. You may obtain |
| 5 | // a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 |
| 6 | |
| 7 | package description |
| 8 | |
| 9 | import ( |
| 10 | "sort" |
| 11 | "strings" |
| 12 | |
| 13 | "github.com/mongodb/mongo-go-driver/x/network/address" |
| 14 | ) |
| 15 | |
| 16 | // Topology represents a description of a mongodb topology |
| 17 | type Topology struct { |
| 18 | Servers []Server |
| 19 | Kind TopologyKind |
| 20 | SessionTimeoutMinutes uint32 |
| 21 | } |
| 22 | |
| 23 | // Server returns the server for the given address. Returns false if the server |
| 24 | // could not be found. |
| 25 | func (t Topology) Server(addr address.Address) (Server, bool) { |
| 26 | for _, server := range t.Servers { |
| 27 | if server.Addr.String() == addr.String() { |
| 28 | return server, true |
| 29 | } |
| 30 | } |
| 31 | return Server{}, false |
| 32 | } |
| 33 | |
| 34 | // TopologyDiff is the difference between two different topology descriptions. |
| 35 | type TopologyDiff struct { |
| 36 | Added []Server |
| 37 | Removed []Server |
| 38 | } |
| 39 | |
| 40 | // DiffTopology compares the two topology descriptions and returns the difference. |
| 41 | func DiffTopology(old, new Topology) TopologyDiff { |
| 42 | var diff TopologyDiff |
| 43 | |
| 44 | // TODO: do this without sorting... |
| 45 | oldServers := serverSorter(old.Servers) |
| 46 | newServers := serverSorter(new.Servers) |
| 47 | |
| 48 | sort.Sort(oldServers) |
| 49 | sort.Sort(newServers) |
| 50 | |
| 51 | i := 0 |
| 52 | j := 0 |
| 53 | for { |
| 54 | if i < len(oldServers) && j < len(newServers) { |
| 55 | comp := strings.Compare(oldServers[i].Addr.String(), newServers[j].Addr.String()) |
| 56 | switch comp { |
| 57 | case 1: |
| 58 | //left is bigger than |
| 59 | diff.Added = append(diff.Added, newServers[j]) |
| 60 | j++ |
| 61 | case -1: |
| 62 | // right is bigger |
| 63 | diff.Removed = append(diff.Removed, oldServers[i]) |
| 64 | i++ |
| 65 | case 0: |
| 66 | i++ |
| 67 | j++ |
| 68 | } |
| 69 | } else if i < len(oldServers) { |
| 70 | diff.Removed = append(diff.Removed, oldServers[i]) |
| 71 | i++ |
| 72 | } else if j < len(newServers) { |
| 73 | diff.Added = append(diff.Added, newServers[j]) |
| 74 | j++ |
| 75 | } else { |
| 76 | break |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | return diff |
| 81 | } |
| 82 | |
| 83 | type serverSorter []Server |
| 84 | |
| 85 | func (ss serverSorter) Len() int { return len(ss) } |
| 86 | func (ss serverSorter) Swap(i, j int) { ss[i], ss[j] = ss[j], ss[i] } |
| 87 | func (ss serverSorter) Less(i, j int) bool { |
| 88 | return strings.Compare(ss[i].Addr.String(), ss[j].Addr.String()) < 0 |
| 89 | } |