feat: DTail fork — server/client feature development

Squashed development of the snonux/dtail fork's product code (internal/, cmd/)
since diverging from mimecast/dtail. Major areas:

- Read/output path: the former "turbo" channel-less path is now the single,
  default server-side read/output path for cat/grep/tail and MapReduce; the old
  channel-based path and its config/env toggles were removed.
- MapReduce: single aggregate implementation (server + serverless) fed directly
  by a processor pipeline, with input-exhausted finalization via the shutdown
  coordinator; high-concurrency and data-race fixes.
- Journal source reads (journal:unit.service) via journalctl, Linux-gated behind
  a journal-v1 capability.
- Auth-key fast reconnect: in-memory per-user public-key cache with TTL/max-keys,
  registered over an authenticated session (AUTHKEY), checked before
  authorized_keys.
- Interactive query reload (--interactive-query) with SESSION START/UPDATE
  generation boundaries and capability negotiation.
- Client-side deadlines: --timeout / --shutdownAfter as context deadlines;
  follow shutdown handling.
- Client logging: diagnostics-only daily log by default, opt-in payload tee via
  --log-payload.
- Numerous correctness fixes (buffer-pool double-recycle races, EOF-sentinel
  leaks, glob-expansion cap, TOCTOU in CSV parsing) with accompanying unit tests.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/internal/mapr/logformat/default_benchmark_test.go b/internal/mapr/logformat/default_benchmark_test.go
new file mode 100644
index 0000000..2eb468e
--- /dev/null
+++ b/internal/mapr/logformat/default_benchmark_test.go
@@ -0,0 +1,44 @@
+package logformat
+
+import (
+	"testing"
+
+	"github.com/mimecast/dtail/internal/mapr"
+)
+
+func BenchmarkDefaultParserMakeFields(b *testing.B) {
+	input := "INFO|20211002-072342|1|default_benchmark_test.go:0|8|14|7|0.21|471h0m21s|" +
+		"MAPREDUCE:STATS|foo=bar|bar=baz|qux=quux|alpha=beta|gamma=delta"
+
+	b.Run("all_fields", func(b *testing.B) {
+		parser, err := NewParser("default", nil)
+		if err != nil {
+			b.Fatalf("Unable to create parser: %s", err.Error())
+		}
+
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			if _, err := parser.MakeFields(input, ""); err != nil {
+				b.Fatalf("Unable to parse input: %s", err.Error())
+			}
+		}
+	})
+
+	b.Run("query_specific", func(b *testing.B) {
+		q, err := mapr.NewQuery(`select count(foo) from STATS where bar eq "baz"`)
+		if err != nil {
+			b.Fatalf("Unable to create query: %s", err.Error())
+		}
+		parser, err := NewParser("default", q)
+		if err != nil {
+			b.Fatalf("Unable to create parser: %s", err.Error())
+		}
+
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			if _, err := parser.MakeFields(input, ""); err != nil {
+				b.Fatalf("Unable to parse input: %s", err.Error())
+			}
+		}
+	})
+}