Initial implementation: NATS->S3 archiver + search/retrieve CLI

logarchiver replaces the plain Vector archiver leg of the centralized
logging stack (argocd-apps #296) with a Go service that archives raw logs
from NATS JetStream to S3 as zstd-compressed, OpenPGP-encrypted, indexed
objects, plus an operator CLI to search the index and retrieve/decrypt
archived logs. It adds the things that outgrew Vector: zstd compression,
encryption keyed from Ben's Vault GPG secrets engine, a searchable
ClickHouse index, and sink-conditional acks (a batch is acknowledged to
JetStream only after the object is durably in S3 AND indexed).

Service (`logarchiver run`):
- Durable JetStream pull consumer (stream LOGS, durable archiver, subject
  filter default logs.k8s.vault.>), explicit acks, independent offsets.
- Batch per subject by size/count/time -> NDJSON -> zstd -> encrypt -> S3
  PUT -> ClickHouse index row -> ack. On any failure the batch is Nak'd and
  redelivered, so nothing is lost on a sink outage.
- Encryption is a wrapped-DEK envelope (container LARC1): the bulk is
  AES-256-GCM framed under a random data key, and only that 32-byte key is
  OpenPGP-encrypted to the engine's public key. This is because the Vault
  GPG engine does whole-payload decrypt only; retrieval round-trips just the
  tiny wrapped key regardless of object size. Public key fetched from the
  engine or a mounted file (configurable); key fingerprint recorded per
  object; periodic pubkey refresh for rotation.
- Prometheus metrics, structured slog, graceful drain on shutdown.

CLI:
- `search` queries the index (subject/host/time) and lists matching objects.
- `fetch` downloads, decrypts via the Vault GPG engine, unzstds and emits
  NDJSON (optionally re-filtered by host/time).
- `init-schema` creates/prints the ClickHouse archive_index DDL.
- cobra `completion` subcommands.

Config via file+env (k8s-friendly, secrets from env), boundaries (NATS/S3/
ClickHouse/Vault) behind interfaces with unit tests (config, batching,
host/subject extraction, crypto roundtrip with a test key, ack-after-persist
with fakes, search query building). go build/vet/test -race clean;
golangci-lint v2 clean. Woodpecker CI: build/test/pre-commit on PR; on v*
tag a container image plus a Gitea binary release + rpm-internal RPM. Docs
per subcommand + architecture + retrieval runbook + deployment drop-in.

Claude-Session: https://claude.ai/code/session_015ur3i7D2azsMAWTSVABApv

internal/index/query.go

@@ -0,0 +1,111 @@
+package index
+
+import (
+	"fmt"
+	"strings"
+	"time"
+)
+
+// SearchQuery describes an index search. Zero-valued fields are omitted.
+type SearchQuery struct {
+	Subject string    // NATS-style glob: '*' = one token, '>' = rest. Empty = any.
+	Host    string    // exact, or a glob containing '*'. Empty = any.
+	From    time.Time // objects whose range overlaps [From,To]
+	To      time.Time
+	Limit   int
+}
+
+// buildSearchSQL renders q into a parameterized ClickHouse SELECT and its args.
+// It is pure so it can be unit-tested without a database. Placeholders use the
+// clickhouse-go positional style (?), matching Query(ctx, sql, args...).
+func buildSearchSQL(database, table string, q SearchQuery) (string, []any) {
+	var (
+		where []string
+		args  []any
+	)
+	if q.Subject != "" {
+		where = append(where, "match(subject, ?)")
+		args = append(args, subjectToRegex(q.Subject))
+	}
+	if q.Host != "" {
+		if strings.Contains(q.Host, "*") {
+			where = append(where, "arrayExists(h -> match(h, ?), hosts)")
+			args = append(args, hostGlobToRegex(q.Host))
+		} else {
+			where = append(where, "has(hosts, ?)")
+			args = append(args, q.Host)
+		}
+	}
+	if !q.From.IsZero() {
+		// object overlaps the window if its max_ts is at/after From.
+		where = append(where, "max_ts >= ?")
+		args = append(args, q.From.UTC())
+	}
+	if !q.To.IsZero() {
+		where = append(where, "min_ts <= ?")
+		args = append(args, q.To.UTC())
+	}
+
+	sql := fmt.Sprintf(
+		"SELECT object_key, bucket, subject, hosts, min_ts, max_ts, event_count, raw_bytes, stored_bytes, key_name, key_fingerprint FROM %s.%s",
+		database, table)
+	if len(where) > 0 {
+		sql += " WHERE " + strings.Join(where, " AND ")
+	}
+	sql += " ORDER BY min_ts, object_key"
+	if q.Limit > 0 {
+		sql += " LIMIT ?"
+		args = append(args, q.Limit)
+	}
+	return sql, args
+}
+
+// subjectToRegex converts a NATS-style subject glob into an anchored regex for
+// ClickHouse match(). '*' matches exactly one dot-delimited token; '>' (only
+// meaningful as the final token) matches one or more trailing tokens. Literal
+// dots and regex metacharacters are escaped.
+func subjectToRegex(glob string) string {
+	tokens := strings.Split(glob, ".")
+	var parts []string
+	for i, tok := range tokens {
+		switch tok {
+		case "*":
+			parts = append(parts, `[^.]+`)
+		case ">":
+			// '>' consumes the rest; emit and stop.
+			if i == 0 {
+				return "^.+$"
+			}
+			return "^" + strings.Join(parts[:i], `\.`) + `(\..+)?$`
+		default:
+			parts = append(parts, regexEscape(tok))
+		}
+	}
+	return "^" + strings.Join(parts, `\.`) + "$"
+}
+
+// hostGlobToRegex converts a host glob (where '*' matches any run of
+// characters, including dots in an FQDN) into an anchored regex for match().
+func hostGlobToRegex(glob string) string {
+	var b strings.Builder
+	b.WriteByte('^')
+	for _, seg := range strings.Split(glob, "*") {
+		b.WriteString(regexEscape(seg))
+		b.WriteString(".*")
+	}
+	// Trim the trailing ".*" added after the last segment, then anchor.
+	out := strings.TrimSuffix(b.String(), ".*")
+	return out + "$"
+}
+
+func regexEscape(s string) string {
+	const meta = `\.+*?()|[]{}^$`
+	var b strings.Builder
+	for _, r := range s {
+		if strings.ContainsRune(meta, r) {
+			b.WriteByte('\\')
+		}
+		b.WriteRune(r)
+	}
+	return b.String()
+}