jarl/internal/render/stats.go

package render

import (
	"net/netip"
	"strconv"
	"strings"

	"jarl/internal/model"
	"jarl/internal/namedconf"
)

// Extras are additions to named's configuration that come from jarld's
// own configuration (jarl.yaml) rather than from the database.
type Extras struct {
	// Stats, when set, makes named publish what Jarl's statistics
	// collector reads.
	Stats *StatsHooks
}

// StatsHooks describe the statistics channel and response log Jarl needs.
type StatsHooks struct {
	Channel     netip.AddrPort // statistics-channels address (loopback)
	LogFile     string         // response log; "" disables response logging
	LogVersions int
	LogSize     string
}

// StatsChannelName is the logging channel Jarl adds for responses.
const StatsChannelName = "jarl_responses"

const statsComment = "Added by Jarl for query statistics (stats in /etc/jarl/jarl.yaml)."

// statsInet is the statistics-channels clause for the collector.
func (h *StatsHooks) statsInet() *namedconf.Stmt {
	addr := h.Channel.Addr().String()
	return namedconf.NewStmt("inet", addr, "port", strconv.Itoa(int(h.Channel.Port())),
		"allow", namedconf.NewBlock(namedconf.NewStmt(addr)))
}

// logChannel is the logging channel the response log is written to.
func (h *StatsHooks) logChannel() *namedconf.Stmt {
	return namedconf.NewStmt("channel", StatsChannelName, namedconf.NewBlock(
		namedconf.NewStmt("file", namedconf.Quoted(h.LogFile), "versions", strconv.Itoa(h.LogVersions), "size", h.LogSize),
		namedconf.NewStmt("print-time", "yes"),
		namedconf.NewStmt("severity", "info"),
	))
}

// statsStatement returns the statistics-channels statement, merged into the
// user's own if there is one.
func (h *StatsHooks) statsStatement(user *model.Option) string {
	if user != nil {
		if st, err := namedconf.ParseOptionValue(user.Name, user.Value); err == nil && st.FirstBlock() != nil {
			b := st.FirstBlock()
			want := namedconf.CompactStmt(h.statsInet())
			for _, s := range b.Stmts {
				if namedconf.CompactStmt(s) == want {
					return optionText(user, 0)
				}
			}
			b.Stmts = append(b.Stmts, h.statsInet())
			return commentLines(user.Comment) + commentBlock("//", statsComment) + namedconf.FormatStmt(st, 0)
		}
		// Unparsable: validation reports it; leave it alone.
		return optionText(user, 0)
	}
	st := namedconf.NewStmt("statistics-channels", namedconf.NewBlock(h.statsInet()))
	return commentBlock("//", statsComment) + namedconf.FormatStmt(st, 0)
}

// loggingStatement returns the logging statement with Jarl's channel and
// the responses category, merged into the user's own if there is one.
func (h *StatsHooks) loggingStatement(user *model.Option) string {
	var st *namedconf.Stmt
	if user != nil {
		var err error
		st, err = namedconf.ParseOptionValue(user.Name, user.Value)
		if err != nil || st.FirstBlock() == nil {
			return optionText(user, 0)
		}
	} else {
		st = namedconf.NewStmt("logging", namedconf.NewBlock())
	}
	b := st.FirstBlock()
	// Channels must be defined before the categories that use them.
	b.Stmts = append([]*namedconf.Stmt{h.logChannel()}, b.Stmts...)
	merged := false
	for _, s := range b.Stmts {
		if s.Keyword() == "category" && strings.EqualFold(s.Arg(0), "responses") && s.FirstBlock() != nil {
			s.FirstBlock().Stmts = append(s.FirstBlock().Stmts, namedconf.NewStmt(StatsChannelName))
			merged = true
		}
	}
	if !merged {
		b.Stmts = append(b.Stmts, namedconf.NewStmt("category", "responses", namedconf.NewBlock(namedconf.NewStmt(StatsChannelName))))
	}
	prefix := ""
	if user != nil {
		prefix = commentLines(user.Comment)
	}
	return prefix + commentBlock("//", statsComment) + namedconf.FormatStmt(st, 0)
}

func commentLines(c string) string {
	if c == "" {
		return ""
	}
	return commentBlock("//", c)
}