| 1 | package host |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | "context" |
| 6 | "errors" |
| 7 | "fmt" |
| 8 | "io" |
| 9 | "sort" |
| 10 | "strings" |
| 11 | |
| 12 | "github.com/aws/aws-sdk-go-v2/aws" |
| 13 | "github.com/aws/aws-sdk-go-v2/credentials" |
| 14 | awss3 "github.com/aws/aws-sdk-go-v2/service/s3" |
| 15 | |
| 16 | "github.com/carlosframework/platform/internal/lease" |
| 17 | "github.com/carlosframework/platform/internal/moves" |
| 18 | "github.com/carlosframework/platform/internal/objstore" |
| 19 | ) |
| 20 | |
| 21 | // The storage probes of the target's report: T4's probe of every store |
| 22 | // bound in the composed environment, and T10's return lane in the source's |
| 23 | // bucket. armPhase1 wires them as moveCfg.ProbeStore and LaneProbe. |
| 24 | |
| 25 | // probeStores is T4 in production (§7.3): for each store bound in the |
| 26 | // composed environment (objstore.EnvNames), with that store's own |
| 27 | // credentials, list one key, then put, get and delete |
| 28 | // .carlos-move-probe/<move id>. It returns the first failing binding's |
| 29 | // prefix with its error. The client is built the way a member app builds |
| 30 | // it from the delivered variables (objstore's delivered contract): static |
| 31 | // credentials, the delivered region, and the endpoint path-style when one |
| 32 | // is delivered. |
| 33 | func probeStores(ctx context.Context, env map[string]string, id string) (string, error) { |
| 34 | for _, p := range storePrefixes(env) { |
| 35 | if err := probeStore(ctx, env, p, id); err != nil { |
| 36 | return p, err |
| 37 | } |
| 38 | } |
| 39 | return "", nil |
| 40 | } |
| 41 | |
| 42 | func probeStore(ctx context.Context, env map[string]string, prefix, id string) error { |
| 43 | bn, rn, en, ak, sk := objstore.EnvNames(prefix) |
| 44 | region := env[rn] |
| 45 | if region == "" { |
| 46 | region = "us-east-1" |
| 47 | } |
| 48 | opts := awss3.Options{ |
| 49 | Region: region, |
| 50 | Credentials: credentials.NewStaticCredentialsProvider(env[ak], env[sk], ""), |
| 51 | RequestChecksumCalculation: aws.RequestChecksumCalculationWhenRequired, |
| 52 | ResponseChecksumValidation: aws.ResponseChecksumValidationWhenRequired, |
| 53 | } |
| 54 | if ep := env[en]; ep != "" { |
| 55 | opts.BaseEndpoint = aws.String(ep) |
| 56 | opts.UsePathStyle = true |
| 57 | } |
| 58 | c := awss3.New(opts) |
| 59 | bucket := aws.String(env[bn]) |
| 60 | key := aws.String(".carlos-move-probe/" + id) |
| 61 | body := []byte("carlos move probe " + id) |
| 62 | if _, err := c.ListObjectsV2(ctx, &awss3.ListObjectsV2Input{Bucket: bucket, MaxKeys: aws.Int32(1)}); err != nil { |
| 63 | return fmt.Errorf("list: %w", err) |
| 64 | } |
| 65 | if _, err := c.PutObject(ctx, &awss3.PutObjectInput{Bucket: bucket, Key: key, Body: bytes.NewReader(body)}); err != nil { |
| 66 | return fmt.Errorf("put: %w", err) |
| 67 | } |
| 68 | out, err := c.GetObject(ctx, &awss3.GetObjectInput{Bucket: bucket, Key: key}) |
| 69 | if err != nil { |
| 70 | return fmt.Errorf("get: %w", err) |
| 71 | } |
| 72 | got, err := io.ReadAll(io.LimitReader(out.Body, 1<<16)) |
| 73 | out.Body.Close() |
| 74 | if err != nil { |
| 75 | return fmt.Errorf("get: %w", err) |
| 76 | } |
| 77 | if !bytes.Equal(got, body) { |
| 78 | return errors.New("get: the probe object read back different bytes") |
| 79 | } |
| 80 | if _, err := c.DeleteObject(ctx, &awss3.DeleteObjectInput{Bucket: bucket, Key: key}); err != nil { |
| 81 | return fmt.Errorf("delete: %w", err) |
| 82 | } |
| 83 | return nil |
| 84 | } |
| 85 | |
| 86 | // laneProbe is T10 in production: put-if-absent then delete-by-version of |
| 87 | // moves/_lane/<id> in the source's bucket. A probe object left by an earlier |
| 88 | // pass whose delete failed is removed by version and the check fails this |
| 89 | // pass; the next one starts clean. |
| 90 | func laneProbe(versioned func(ctx context.Context, bucket, region string) (lease.VersionedStore, error)) func(context.Context, string, string, string) error { |
| 91 | return func(ctx context.Context, bucket, region, id string) error { |
| 92 | vs, err := versioned(ctx, bucket, region) |
| 93 | if err != nil { |
| 94 | return err |
| 95 | } |
| 96 | key := moves.LaneKey(id) |
| 97 | ver, err := vs.PutIfAbsent(ctx, bucket, key, []byte(`{"probe":"`+id+`"}`)) |
| 98 | if errors.Is(err, lease.ErrExists) { |
| 99 | vers, lerr := vs.ListVersions(ctx, bucket, key) |
| 100 | if lerr != nil { |
| 101 | return fmt.Errorf("a probe object is left and cannot be listed: %w", lerr) |
| 102 | } |
| 103 | for _, v := range vers { |
| 104 | if v.Key == key { |
| 105 | if derr := vs.DeleteVersion(ctx, bucket, key, v.VersionID); derr != nil { |
| 106 | return derr |
| 107 | } |
| 108 | } |
| 109 | } |
| 110 | return errors.New("a probe object was left by an earlier pass; removed") |
| 111 | } |
| 112 | if err != nil { |
| 113 | return err |
| 114 | } |
| 115 | return vs.DeleteVersion(ctx, bucket, key, ver) |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | // storePrefixes are the store bindings in an environment: every prefix P |
| 120 | // with P_BUCKET, P_ACCESS_KEY and P_SECRET_KEY set (objstore.EnvNames). |
| 121 | func storePrefixes(env map[string]string) []string { |
| 122 | var out []string |
| 123 | for name := range env { |
| 124 | p, ok := strings.CutSuffix(name, "_BUCKET") |
| 125 | if !ok || p == "" { |
| 126 | continue |
| 127 | } |
| 128 | _, _, _, ak, sk := objstore.EnvNames(p) |
| 129 | if env[ak] != "" && env[sk] != "" { |
| 130 | out = append(out, p) |
| 131 | } |
| 132 | } |
| 133 | sort.Strings(out) |
| 134 | return out |
| 135 | } |
| 136 | |
amadan