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, 89 insertions, 0 deletions

diff --git a/internal/clients/runtime_boundary_test.go b/internal/clients/runtime_boundary_test.go
new file mode 100644
index 0000000..9947865
--- /dev/null
+++ b/internal/clients/runtime_boundary_test.go
@@ -0,0 +1,89 @@
+package clients
+
+import (
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/mimecast/dtail/internal/color"
+	"github.com/mimecast/dtail/internal/config"
+)
+
+func TestNewClientRuntimeBoundaryDefaults(t *testing.T) {
+	runtime := newClientRuntimeBoundary(config.RuntimeConfig{})
+
+	if runtime.SSHPort() != 2222 {
+		t.Fatalf("Expected default SSH port 2222, got %d", runtime.SSHPort())
+	}
+	if runtime.SSHConnectTimeout() != 2*time.Second {
+		t.Fatalf("Expected default timeout 2s, got %v", runtime.SSHConnectTimeout())
+	}
+	if runtime.InterruptPause() != 3*time.Second {
+		t.Fatalf("Expected default interrupt pause 3s, got %v", runtime.InterruptPause())
+	}
+	if got := runtime.output.PaintMaprRawQuery("select 1"); got != "select 1" {
+		t.Fatalf("Expected plain raw query output, got %q", got)
+	}
+}
+
+func TestNewClientRuntimeBoundaryUsesConfiguredSSHSettings(t *testing.T) {
+	runtime := newClientRuntimeBoundary(config.RuntimeConfig{
+		Common: &config.CommonConfig{
+			SSHPort:             4022,
+			SSHConnectTimeoutMs: 4500,
+		},
+	})
+
+	if runtime.SSHPort() != 4022 {
+		t.Fatalf("Expected configured SSH port 4022, got %d", runtime.SSHPort())
+	}
+	if runtime.SSHConnectTimeout() != 4500*time.Millisecond {
+		t.Fatalf("Expected configured timeout 4.5s, got %v", runtime.SSHConnectTimeout())
+	}
+}
+
+func TestClientOutputFormatterColorModes(t *testing.T) {
+	plain := newClientOutputFormatter(nil)
+	if got := plain.FormatInterruptMessage(1, "hello"); got != " hello" {
+		t.Fatalf("Expected plain interrupt message, got %q", got)
+	}
+	if got := plain.PaintMaprRawQuery("select 1"); got != "select 1" {
+		t.Fatalf("Expected plain raw query, got %q", got)
+	}
+
+	cfg := &config.ClientConfig{TermColorsEnable: true}
+	cfg.TermColors.Client.ClientFg = color.FgBlack
+	cfg.TermColors.Client.ClientBg = color.BgYellow
+	cfg.TermColors.Client.ClientAttr = color.AttrBold
+	cfg.TermColors.MaprTable.RawQueryFg = color.FgCyan
+	cfg.TermColors.MaprTable.RawQueryBg = color.BgBlack
+	cfg.TermColors.MaprTable.RawQueryAttr = color.AttrUnderline
+	cfg.TermColors.MaprTable.HeaderFg = color.FgWhite
+	cfg.TermColors.MaprTable.HeaderBg = color.BgBlue
+	cfg.TermColors.MaprTable.HeaderAttr = color.AttrBold
+	cfg.TermColors.MaprTable.HeaderDelimiterFg = color.FgWhite
+	cfg.TermColors.MaprTable.HeaderDelimiterBg = color.BgBlue
+	cfg.TermColors.MaprTable.HeaderDelimiterAttr = color.AttrDim
+	cfg.TermColors.MaprTable.HeaderSortKeyAttr = color.AttrUnderline
+	cfg.TermColors.MaprTable.HeaderGroupKeyAttr = color.AttrReverse
+	cfg.TermColors.MaprTable.DataFg = color.FgWhite
+	cfg.TermColors.MaprTable.DataBg = color.BgBlue
+	cfg.TermColors.MaprTable.DataAttr = color.AttrNone
+	cfg.TermColors.MaprTable.DelimiterFg = color.FgWhite
+	cfg.TermColors.MaprTable.DelimiterBg = color.BgBlue
+	cfg.TermColors.MaprTable.DelimiterAttr = color.AttrDim
+
+	colored := newClientOutputFormatter(cfg)
+	if got := colored.FormatInterruptMessage(0, "hello"); got != " hello" {
+		t.Fatalf("Expected first interrupt line to stay plain, got %q", got)
+	}
+	if got := colored.FormatInterruptMessage(1, "hello"); !strings.Contains(got, "\x1b[") {
+		t.Fatalf("Expected colored interrupt output, got %q", got)
+	}
+	if got := colored.PaintMaprRawQuery("select 1"); !strings.Contains(got, "\x1b[") {
+		t.Fatalf("Expected colored raw query output, got %q", got)
+	}
+	if colored.MaprResultRenderer() == nil {
+		t.Fatal("Expected non-nil mapreduce result renderer")
+	}
+}