| 1 | package hostactors |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "errors" |
| 6 | "sort" |
| 7 | "strings" |
| 8 | |
| 9 | "github.com/carlosframework/platform/internal/release" |
| 10 | ) |
| 11 | |
| 12 | // Box and group roles (region HA spec 2 §7, A11-1). A box's role says |
| 13 | // whether placement may choose it: the default role may be chosen, and |
| 14 | // legacy and platform never are, for a create, a relocation target or a |
| 15 | // move target. The box keeps the instances it has (H25). |
| 16 | // |
| 17 | // The region's group entry carries a role too. Every box automatic |
| 18 | // enrollment admits from the group takes the group's role in the same |
| 19 | // roster write, and changing the group's role changes the role of every |
| 20 | // box enrolled from it, so a replacement launched after the group was |
| 21 | // excluded is never placeable, even for a moment. |
| 22 | // |
| 23 | // The roster stores the default role as "" so a roster written before |
| 24 | // roles existed reads as all-default. |
| 25 | const ( |
| 26 | RoleDefault = "" |
| 27 | RoleLegacy = "legacy" |
| 28 | RolePlatform = "platform" |
| 29 | ) |
| 30 | |
| 31 | // ErrRole is a role name a box or group cannot take. |
| 32 | var ErrRole = errors.New("hostactors: not a role this box or group can take") |
| 33 | |
| 34 | // ParseBoxRole reads an operator's box role: default, legacy or platform. |
| 35 | func ParseBoxRole(s string) (string, error) { |
| 36 | switch strings.TrimSpace(s) { |
| 37 | case "default": |
| 38 | return RoleDefault, nil |
| 39 | case RoleLegacy: |
| 40 | return RoleLegacy, nil |
| 41 | case RolePlatform: |
| 42 | return RolePlatform, nil |
| 43 | } |
| 44 | return "", ErrRole |
| 45 | } |
| 46 | |
| 47 | // ParseGroupRole reads an operator's group role: default or legacy. A |
| 48 | // group is never the platform box. |
| 49 | func ParseGroupRole(s string) (string, error) { |
| 50 | switch strings.TrimSpace(s) { |
| 51 | case "default": |
| 52 | return RoleDefault, nil |
| 53 | case RoleLegacy: |
| 54 | return RoleLegacy, nil |
| 55 | } |
| 56 | return "", ErrRole |
| 57 | } |
| 58 | |
| 59 | // RoleName is the operator's word for a stored role. |
| 60 | func RoleName(role string) string { |
| 61 | if role == RoleDefault { |
| 62 | return "default" |
| 63 | } |
| 64 | return role |
| 65 | } |
| 66 | |
| 67 | func validBoxRole(role string) bool { |
| 68 | return role == RoleDefault || role == RoleLegacy || role == RolePlatform |
| 69 | } |
| 70 | |
| 71 | func validGroupRole(role string) bool { return role == RoleDefault || role == RoleLegacy } |
| 72 | |
| 73 | // SetBoxRole sets one box's role in a fresh roster write over o. The box |
| 74 | // must be enrolled and not retired. Setting the role it already has |
| 75 | // changes nothing and returns o. |
| 76 | func (d Directory) SetBoxRole(ctx context.Context, sg release.Signer, o Observed, ref, role string) (Observed, error) { |
| 77 | if !validBoxRole(role) { |
| 78 | return Observed{}, ErrRole |
| 79 | } |
| 80 | b, ok := o.Roster.Boxes[ref] |
| 81 | if !ok || b.State == "retired" { |
| 82 | return Observed{}, ErrRoster |
| 83 | } |
| 84 | if b.Role == role { |
| 85 | return o, nil |
| 86 | } |
| 87 | r := Clone(o.Roster) |
| 88 | b = r.Boxes[ref] |
| 89 | b.Role = role |
| 90 | r.Boxes[ref] = b |
| 91 | return d.Replace(ctx, sg, o, r) |
| 92 | } |
| 93 | |
| 94 | // GroupMembers returns, sorted, the boxes enrolled from region's group |
| 95 | // that are not retired: the boxes a group role change applies to. |
| 96 | func GroupMembers(r Roster, region string) []string { |
| 97 | g, ok := r.Regions[region] |
| 98 | if !ok || g.GroupName == "" { |
| 99 | return nil |
| 100 | } |
| 101 | var out []string |
| 102 | for ref, b := range r.Boxes { |
| 103 | if b.Region == region && b.Group == g.GroupName && b.State != "retired" { |
| 104 | out = append(out, ref) |
| 105 | } |
| 106 | } |
| 107 | sort.Strings(out) |
| 108 | return out |
| 109 | } |
| 110 | |
| 111 | // SetGroupRole sets region's group role and, in the same roster write, the |
| 112 | // role of every box enrolled from that group (GroupMembers). The region |
| 113 | // must have a group. It returns the roster and the boxes it set. |
| 114 | func (d Directory) SetGroupRole(ctx context.Context, sg release.Signer, o Observed, region, role string) (Observed, []string, error) { |
| 115 | if !validGroupRole(role) { |
| 116 | return Observed{}, nil, ErrRole |
| 117 | } |
| 118 | g, ok := o.Roster.Regions[region] |
| 119 | if !ok || g.GroupName == "" { |
| 120 | return Observed{}, nil, ErrRoster |
| 121 | } |
| 122 | members := GroupMembers(o.Roster, region) |
| 123 | changed := g.Role != role |
| 124 | for _, ref := range members { |
| 125 | changed = changed || o.Roster.Boxes[ref].Role != role |
| 126 | } |
| 127 | if !changed { |
| 128 | return o, members, nil |
| 129 | } |
| 130 | r := Clone(o.Roster) |
| 131 | g.Role = role |
| 132 | r.Regions[region] = g |
| 133 | for _, ref := range members { |
| 134 | b := r.Boxes[ref] |
| 135 | b.Role = role |
| 136 | r.Boxes[ref] = b |
| 137 | } |
| 138 | next, err := d.Replace(ctx, sg, o, r) |
| 139 | if err != nil { |
| 140 | return Observed{}, nil, err |
| 141 | } |
| 142 | return next, members, nil |
| 143 | } |
| 144 | |
amadan