| 1 | package appconfig |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "encoding/json" |
| 6 | "fmt" |
| 7 | |
| 8 | "github.com/carlosframework/platform/internal/release" |
| 9 | ) |
| 10 | |
| 11 | // SwapPolicy is an app's swap policy (zero-downtime spec §4.1) with its |
| 12 | // defaults filled in. It lives in the DEFAULT bundle beside exec_delivery, |
| 13 | // which is where plan 5's boxes read it; a named environment never carries it. |
| 14 | type SwapPolicy struct { |
| 15 | Swap string // SwapOverlap or SwapHold |
| 16 | Concurrency int // 1 or more |
| 17 | } |
| 18 | |
| 19 | // PolicyOf reads m's swap fields with the defaults filled in, the way the |
| 20 | // box's rollout.PolicyFromManifest does. nil is an app never configured. A |
| 21 | // stored mode this binary does not know reads as hold: missing or |
| 22 | // unverifiable policy never permits an overlap (spec §4.2). |
| 23 | func PolicyOf(m *Manifest) SwapPolicy { |
| 24 | p := SwapPolicy{Swap: SwapOverlap, Concurrency: 1} |
| 25 | if m == nil { |
| 26 | return p |
| 27 | } |
| 28 | if m.Swap != "" && m.Swap != SwapOverlap { |
| 29 | p.Swap = SwapHold |
| 30 | } |
| 31 | if m.SwapConcurrency > 1 { |
| 32 | p.Concurrency = m.SwapConcurrency |
| 33 | } |
| 34 | return p |
| 35 | } |
| 36 | |
| 37 | // GetSwapPolicy reads the app's policy. No config.json is the defaults, not |
| 38 | // an error (Get's own convention). |
| 39 | func GetSwapPolicy(ctx context.Context, s release.Store, acct, app string) (SwapPolicy, error) { |
| 40 | m, err := Get(ctx, s, acct, app) |
| 41 | if err != nil { |
| 42 | return SwapPolicy{}, err |
| 43 | } |
| 44 | return PolicyOf(m), nil |
| 45 | } |
| 46 | |
| 47 | // SetSwapPolicy writes the policy into the default bundle by the CAS |
| 48 | // read-modify-write SetExecDeliveryAt uses, and returns what is stored. swap |
| 49 | // "" and concurrency 0 leave their half alone. |
| 50 | // |
| 51 | // Defaults are stored as ABSENT keys, so an app set back to overlap/1 has the |
| 52 | // bytes it had before. A call that changes nothing writes nothing and touches |
| 53 | // nothing: setting the defaults on an app with no config.json never creates |
| 54 | // one. A first non-default policy does create one, holding no vars, and |
| 55 | // config sync leaves an instance whose config file is absent as it is for |
| 56 | // such a bundle (renderExecConfig's keepAbsent), so that first write |
| 57 | // restarts nothing (Astra plan 6 R1 #1). |
| 58 | func SetSwapPolicy(ctx context.Context, s release.Store, acct, app, swap string, concurrency int) (claimResult0 SwapPolicy, claimResult1 error) { |
| 59 | claimResult1 = release.WithAppMutation(ctx, s, acct, app, "appconfig.SetSwapPolicy", func(claimContext context.Context) error { |
| 60 | claimResult0, claimResult1 = claimRawSetSwapPolicy(claimContext, s, acct, app, swap, concurrency) |
| 61 | return claimResult1 |
| 62 | }) |
| 63 | return |
| 64 | } |
| 65 | |
| 66 | // claimRawSetSwapPolicy is the unwrapped implementation of SetSwapPolicy, |
| 67 | // called from within the WithAppMutation wrapper. |
| 68 | func claimRawSetSwapPolicy(ctx context.Context, s release.Store, acct, app, swap string, concurrency int) (SwapPolicy, error) { |
| 69 | if !release.ValidAccount(acct) { |
| 70 | return SwapPolicy{}, fmt.Errorf("config: invalid account %q", acct) |
| 71 | } |
| 72 | if !release.ValidApp(app) { |
| 73 | return SwapPolicy{}, fmt.Errorf("config: invalid app %q", app) |
| 74 | } |
| 75 | if !ValidSwap(swap) { |
| 76 | return SwapPolicy{}, fmt.Errorf("config: invalid swap %q, want %q or %q", swap, SwapOverlap, SwapHold) |
| 77 | } |
| 78 | if !ValidSwapConcurrency(concurrency) { |
| 79 | return SwapPolicy{}, fmt.Errorf("config: invalid swap_concurrency %d, want 1 or more", concurrency) |
| 80 | } |
| 81 | key := Key(acct, app) |
| 82 | m, etag, _, err := getForWriteAt(ctx, s, key, app) |
| 83 | if err != nil { |
| 84 | return SwapPolicy{}, err |
| 85 | } |
| 86 | next := m |
| 87 | switch swap { |
| 88 | case SwapOverlap: |
| 89 | next.Swap = "" |
| 90 | case SwapHold: |
| 91 | next.Swap = SwapHold |
| 92 | } |
| 93 | switch { |
| 94 | case concurrency == 1: |
| 95 | next.SwapConcurrency = 0 |
| 96 | case concurrency > 1: |
| 97 | next.SwapConcurrency = concurrency |
| 98 | } |
| 99 | if next.Swap == m.Swap && next.SwapConcurrency == m.SwapConcurrency { |
| 100 | return PolicyOf(&m), nil |
| 101 | } |
| 102 | next.Schema, next.App = 1, app |
| 103 | raw, err := json.MarshalIndent(next, "", " ") |
| 104 | if err != nil { |
| 105 | return SwapPolicy{}, err |
| 106 | } |
| 107 | if _, err := s.Put(ctx, key, raw, etag); err != nil { |
| 108 | return SwapPolicy{}, err |
| 109 | } |
| 110 | // A policy change is a config change for the fast loop (apply's doc |
| 111 | // comment): best-effort, since the write above has landed. |
| 112 | touchLogged(ctx, s, acct, app) |
| 113 | return PolicyOf(&next), nil |
| 114 | } |
| 115 | |
amadan