| 1 | package stopevidence |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "errors" |
| 6 | "path/filepath" |
| 7 | "sort" |
| 8 | "time" |
| 9 | |
| 10 | "github.com/carlosframework/platform/internal/activator" |
| 11 | "github.com/carlosframework/platform/internal/cgroup" |
| 12 | "github.com/carlosframework/platform/internal/controlname" |
| 13 | ) |
| 14 | |
| 15 | var ( |
| 16 | ErrFence = errors.New("stopevidence: matching stop fence required") |
| 17 | ErrNoCgroupEvidence = errors.New("stopevidence: cgroup observation required") |
| 18 | ErrPopulated = errors.New("stopevidence: cgroup populated") |
| 19 | ErrMembers = errors.New("stopevidence: cgroup has members") |
| 20 | ErrReplicatorsOpen = errors.New("stopevidence: replicators not closed") |
| 21 | ErrFDHolders = errors.New("stopevidence: database descriptors still held") |
| 22 | ) |
| 23 | |
| 24 | type Inputs struct { |
| 25 | Host string |
| 26 | Generation uint64 |
| 27 | Fence *activator.StopEvidence |
| 28 | // Cgroup is the host's PARENT handle (cgroup.Manager.OpenCleanup), never |
| 29 | // one generation's child: under the generation layout the parent is |
| 30 | // empty only when every generation is (zero-downtime spec §7.3), and its |
| 31 | // Members walks every cgroup below it. |
| 32 | Cgroup interface { |
| 33 | Populated() (bool, error) |
| 34 | Members() ([]int, error) |
| 35 | } |
| 36 | DBPaths []string |
| 37 | ProcRoot string |
| 38 | ReplicatorsClosed bool |
| 39 | } |
| 40 | |
| 41 | type Evidence struct { |
| 42 | Host string |
| 43 | Generation uint64 |
| 44 | CheckedAt time.Time |
| 45 | FenceClosed bool |
| 46 | SpawnAttemptsDrained bool |
| 47 | CgroupUnpopulated bool |
| 48 | CgroupMembersEmpty bool |
| 49 | ReplicatorsClosed bool |
| 50 | FDScanComplete bool |
| 51 | CheckedPaths []string |
| 52 | ProcRoot string |
| 53 | } |
| 54 | |
| 55 | func Collect(ctx context.Context, in Inputs) (Evidence, error) { |
| 56 | if ctx == nil { |
| 57 | return Evidence{}, ErrInvalidInput |
| 58 | } |
| 59 | if err := ctx.Err(); err != nil { |
| 60 | return Evidence{}, err |
| 61 | } |
| 62 | if !controlname.ValidHostShape(in.Host) || in.Generation == 0 { |
| 63 | return Evidence{}, ErrInvalidInput |
| 64 | } |
| 65 | if in.Fence == nil || !in.Fence.Matches(in.Host, in.Generation) { |
| 66 | return Evidence{}, ErrFence |
| 67 | } |
| 68 | if in.Cgroup == nil { |
| 69 | return Evidence{}, ErrNoCgroupEvidence |
| 70 | } |
| 71 | if !in.ReplicatorsClosed { |
| 72 | return Evidence{}, ErrReplicatorsOpen |
| 73 | } |
| 74 | if len(in.DBPaths) == 0 { |
| 75 | return Evidence{}, ErrInvalidInput |
| 76 | } |
| 77 | seen := map[string]bool{} |
| 78 | for _, db := range in.DBPaths { |
| 79 | if !filepath.IsAbs(db) { |
| 80 | return Evidence{}, ErrInvalidInput |
| 81 | } |
| 82 | db = filepath.Clean(db) |
| 83 | seen[db], seen[db+"-wal"], seen[db+"-shm"] = true, true, true |
| 84 | } |
| 85 | paths := make([]string, 0, len(seen)) |
| 86 | for path := range seen { |
| 87 | paths = append(paths, path) |
| 88 | } |
| 89 | sort.Strings(paths) |
| 90 | populated, err := in.Cgroup.Populated() |
| 91 | if err != nil { |
| 92 | return Evidence{}, err |
| 93 | } |
| 94 | if populated { |
| 95 | return Evidence{}, ErrPopulated |
| 96 | } |
| 97 | members, err := in.Cgroup.Members() |
| 98 | if err != nil { |
| 99 | return Evidence{}, err |
| 100 | } |
| 101 | if len(members) != 0 { |
| 102 | return Evidence{}, ErrMembers |
| 103 | } |
| 104 | root := in.ProcRoot |
| 105 | if root == "" { |
| 106 | root = "/proc" |
| 107 | } |
| 108 | holders, err := scanFDs(ctx, root, paths) |
| 109 | if err != nil { |
| 110 | return Evidence{}, err |
| 111 | } |
| 112 | if len(holders) != 0 { |
| 113 | return Evidence{}, ErrFDHolders |
| 114 | } |
| 115 | if err := ctx.Err(); err != nil { |
| 116 | return Evidence{}, err |
| 117 | } |
| 118 | return Evidence{ |
| 119 | Host: in.Host, Generation: in.Generation, CheckedAt: time.Now().UTC(), |
| 120 | FenceClosed: true, SpawnAttemptsDrained: true, |
| 121 | CgroupUnpopulated: true, CgroupMembersEmpty: true, |
| 122 | ReplicatorsClosed: true, FDScanComplete: true, |
| 123 | CheckedPaths: paths, ProcRoot: root, |
| 124 | }, nil |
| 125 | } |
| 126 | |
| 127 | func Cleanup(ctx context.Context, c *cgroup.Cleanup) error { |
| 128 | if c == nil { |
| 129 | return ErrInvalidInput |
| 130 | } |
| 131 | return c.KillAndEmpty(ctx) |
| 132 | } |
| 133 | |
amadan