v0.13.0 doc update, refactor, http/tcp chain source and sink added

src/internal/chain/proto.go

@@ -0,0 +1,98 @@
+package chain
+
+import (
+	"encoding/json"
+	"fmt"
+	"logwisp/src/internal/core"
+	"math/rand/v2"
+	"time"
+)
+
+// ProtocolVersion is declared in the hello preamble
+const ProtocolVersion = 1
+
+// Hello is the first NDJSON line sent by the dialing side after connect.
+// Reserved for future revisions: auth credential, feature flags (ack, compression).
+type Hello struct {
+	LogWisp int    `json:"logwisp"`
+	Node    string `json:"node,omitempty"`
+	// Auth     string   `json:"auth,omitempty"`
+	// Features []string `json:"features,omitempty"`
+}
+
+// HTTP transport mapping of the chain protocol.
+// Hello preamble equivalent: protocol + node carried as request headers.
+// Reserved extension point: Authorization header for auth, TLS at transport.
+const (
+	HeaderProtocol    = "X-Logwisp-Protocol"
+	HeaderNode        = "X-Logwisp-Node"
+	HeaderAccepted    = "X-Logwisp-Accepted"
+	ContentTypeNDJSON = "application/x-ndjson"
+)
+
+// EncodeHello serializes a newline-terminated hello preamble
+func EncodeHello(node string) ([]byte, error) {
+	b, err := json.Marshal(Hello{LogWisp: ProtocolVersion, Node: node})
+	if err != nil {
+		return nil, err
+	}
+	return append(b, '\n'), nil
+}
+
+// DecodeHello parses and validates a hello preamble line
+func DecodeHello(line []byte) (Hello, error) {
+	var h Hello
+	if err := json.Unmarshal(line, &h); err != nil {
+		return h, fmt.Errorf("malformed hello: %w", err)
+	}
+	if h.LogWisp != ProtocolVersion {
+		return h, fmt.Errorf("unsupported protocol version: %d", h.LogWisp)
+	}
+	return h, nil
+}
+
+// DecodeEntry parses a canonical LogEntry line and applies the node trust policy
+func DecodeEntry(line []byte, connNode string, trustNode bool) (core.LogEntry, error) {
+	var entry core.LogEntry
+	if err := json.Unmarshal(line, &entry); err != nil {
+		return core.LogEntry{}, err
+	}
+	if entry.Time.IsZero() {
+		entry.Time = time.Now()
+	}
+	if entry.Node == "" || !trustNode {
+		entry.Node = connNode
+	}
+	entry.RawSize = int64(len(line))
+	return entry, nil
+}
+
+// EntryFromEvent extracts the structured entry, stamping node identity at
+// first hop. Second return is true when synthesized from a formatted payload.
+func EntryFromEvent(event core.TransportEvent, node, fallbackSource string) (core.LogEntry, bool) {
+	entry := event.Entry
+	synthesized := false
+	if entry.Time.IsZero() {
+		synthesized = true
+		entry = core.LogEntry{
+			Time:    event.Time,
+			Source:  fallbackSource,
+			Message: string(event.Payload),
+		}
+	}
+	if entry.Node == "" {
+		entry.Node = node
+	}
+	return entry, synthesized
+}
+
+// BackoffDelay computes exponential backoff with ±20% jitter
+func BackoffDelay(minD, maxD time.Duration, failures int) time.Duration {
+	d := maxD
+	if failures < 63 {
+		if v := minD << uint(failures-1); v > 0 && v < maxD {
+			d = v
+		}
+	}
+	return d - d/5 + time.Duration(rand.Int64N(int64(2*d/5)+1))
+}