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, 39 insertions, 3 deletions

diff --git a/internal/mapr/logformat/default_test.go b/internal/mapr/logformat/default_test.go
index 4eae81b..992a052 100644
--- a/internal/mapr/logformat/default_test.go
+++ b/internal/mapr/logformat/default_test.go
@@ -3,6 +3,8 @@ package logformat
 import (
 	"fmt"
 	"testing"
+
+	"github.com/mimecast/dtail/internal/mapr"
 )
 
 func TestDefaultLogFormat(t *testing.T) {
@@ -23,7 +25,7 @@ func TestDefaultLogFormat(t *testing.T) {
 	}
 
 	for _, input := range inputs {
-		fields, err := parser.MakeFields(input)
+		fields, err := parser.MakeFields(input, "")
 
 		if err != nil {
 			t.Errorf("Parser unable to make fields: %s", err.Error())
@@ -86,12 +88,46 @@ func TestDefaultLogFormat(t *testing.T) {
 		}
 	}
 
-	fields, err := parser.MakeFields("foozoo=bar|bazbay")
+	fields, err := parser.MakeFields("foozoo=bar|bazbay", "")
 	if err != nil && err != ErrIgnoreFields {
-		t.Errorf(err.Error())
+		t.Errorf("%s", err.Error())
 	}
 
 	if _, ok := fields["foo"]; ok {
 		t.Errorf("Expected fiending field 'foo', but found it\n")
 	}
 }
+
+func TestDefaultLogFormatQuerySpecificFields(t *testing.T) {
+	q, err := mapr.NewQuery(`select count(foo) from STATS where $hostname eq "testhost"`)
+	if err != nil {
+		t.Fatalf("Unable to create query: %s", err.Error())
+	}
+
+	parser, err := NewParser("default", q)
+	if err != nil {
+		t.Fatalf("Unable to create parser: %s", err.Error())
+	}
+
+	fields, err := parser.MakeFields(
+		"INFO|20211002-072342|1|default_test.go:0|8|14|7|0.21|471h0m21s|MAPREDUCE:STATS|foo=bar|bar=baz",
+		"",
+	)
+	if err != nil {
+		t.Fatalf("Parser unable to make fields: %s", err.Error())
+	}
+
+	requiredFields := []string{"foo", "$hostname"}
+	for _, field := range requiredFields {
+		if _, ok := fields[field]; !ok {
+			t.Errorf("Expected query-specific field '%s' to be present", field)
+		}
+	}
+
+	omittedFields := []string{"bar", "$time", "$pid", "$line"}
+	for _, field := range omittedFields {
+		if _, ok := fields[field]; ok {
+			t.Errorf("Expected query-specific field '%s' to be omitted", field)
+		}
+	}
+}