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refactor: make QueryLoggingResolver read the hostname on creation
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Remove that code from util and the use of globals.

Partly move away from calling the value a "hostname" since it's more of
an instance ID, especially if you run more than one per host.
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ThinkChaos committed Sep 4, 2024
1 parent 8c3d858 commit 70afa43
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Showing 10 changed files with 63 additions and 106 deletions.
2 changes: 1 addition & 1 deletion querylog/database_writer.go
Original file line number Diff line number Diff line change
Expand Up @@ -176,7 +176,7 @@ func (d *DatabaseWriter) Write(entry *LogEntry) {
EffectiveTLDP: eTLD,
Answer: entry.Answer,
ResponseCode: entry.ResponseCode,
Hostname: util.HostnameString(),
Hostname: entry.BlockyInstance,
}

d.lock.Lock()
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2 changes: 1 addition & 1 deletion querylog/file_writer.go
Original file line number Diff line number Diff line change
Expand Up @@ -115,7 +115,7 @@ func createQueryLogRow(logEntry *LogEntry) []string {
logEntry.ResponseCode,
logEntry.ResponseType,
logEntry.QuestionType,
util.HostnameString(),
logEntry.BlockyInstance,
}
}

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3 changes: 1 addition & 2 deletions querylog/logger_writer.go
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,6 @@ import (
"strings"

"github.com/0xERR0R/blocky/log"
"github.com/0xERR0R/blocky/util"
"github.com/sirupsen/logrus"
)

Expand Down Expand Up @@ -40,7 +39,7 @@ func LogEntryFields(entry *LogEntry) logrus.Fields {
"question_type": entry.QuestionType,
"answer": entry.Answer,
"duration_ms": entry.DurationMs,
"hostname": util.HostnameString(),
"instance": entry.BlockyInstance,
})
}

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1 change: 0 additions & 1 deletion querylog/logger_writer_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -51,7 +51,6 @@ var _ = Describe("LoggerWriter", func() {
Expect(fields).Should(HaveKeyWithValue("duration_ms", entry.DurationMs))
Expect(fields).Should(HaveKeyWithValue("question_type", entry.QuestionType))
Expect(fields).Should(HaveKeyWithValue("response_code", entry.ResponseCode))
Expect(fields).Should(HaveKey("hostname"))

Expect(fields).ShouldNot(HaveKey("client_names"))
Expect(fields).ShouldNot(HaveKey("question_name"))
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1 change: 1 addition & 0 deletions querylog/writer.go
Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@ type LogEntry struct {
QuestionType string
QuestionName string
Answer string
BlockyInstance string
}

type Writer interface {
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46 changes: 37 additions & 9 deletions resolver/query_logging_resolver.go
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,10 @@ package resolver

import (
"context"
"errors"
"fmt"
"os"
"strings"
"time"

"github.com/0xERR0R/blocky/config"
Expand All @@ -25,8 +29,9 @@ type QueryLoggingResolver struct {
NextResolver
typed

logChan chan *querylog.LogEntry
writer querylog.Writer
logChan chan *querylog.LogEntry
writer querylog.Writer
instanceID string
}

func GetQueryLoggingWriter(ctx context.Context, cfg config.QueryLog) (querylog.Writer, error) {
Expand Down Expand Up @@ -58,7 +63,7 @@ func GetQueryLoggingWriter(ctx context.Context, cfg config.QueryLog) (querylog.W
}

// NewQueryLoggingResolver returns a new resolver instance
func NewQueryLoggingResolver(ctx context.Context, cfg config.QueryLog) *QueryLoggingResolver {
func NewQueryLoggingResolver(ctx context.Context, cfg config.QueryLog) (*QueryLoggingResolver, error) {
logger := log.PrefixedLog(queryLoggingResolverType)

var writer querylog.Writer
Expand Down Expand Up @@ -86,14 +91,20 @@ func NewQueryLoggingResolver(ctx context.Context, cfg config.QueryLog) *QueryLog
cfg.Type = config.QueryLogTypeConsole
}

instanceID, err := readInstanceID("/etc/hostname")
if err != nil {
return nil, err
}

logChan := make(chan *querylog.LogEntry, logChanCap)

resolver := QueryLoggingResolver{
configurable: withConfig(&cfg),
typed: withType(queryLoggingResolverType),

logChan: logChan,
writer: writer,
logChan: logChan,
writer: writer,
instanceID: instanceID,
}

go resolver.writeLog(ctx)
Expand All @@ -103,7 +114,7 @@ func NewQueryLoggingResolver(ctx context.Context, cfg config.QueryLog) *QueryLog
go resolver.periodicCleanUp(ctx)
}

return &resolver
return &resolver, nil
}

// triggers periodically cleanup of old log files
Expand Down Expand Up @@ -170,9 +181,10 @@ func (r *QueryLoggingResolver) createLogEntry(request *model.Request, response *
start time.Time, durationMs int64,
) *querylog.LogEntry {
entry := querylog.LogEntry{
Start: start,
ClientIP: "0.0.0.0",
ClientNames: []string{"none"},
Start: start,
ClientIP: "0.0.0.0",
ClientNames: []string{"none"},
BlockyInstance: r.instanceID,
}

for _, f := range r.cfg.Fields {
Expand Down Expand Up @@ -227,3 +239,19 @@ func (r *QueryLoggingResolver) writeLog(ctx context.Context) {
}
}
}

func readInstanceID(file string) (string, error) {
// Prefer /etc/hostname over os.Hostname to allow easy differentiation in a Docker Swarm
// See details in https://github.com/0xERR0R/blocky/pull/756
hn, fErr := os.ReadFile(file)
if fErr == nil {
return strings.TrimSpace(string(hn)), nil
}

hostname, osErr := os.Hostname()
if osErr == nil {
return hostname, nil
}

return "", fmt.Errorf("cannot determine instance ID: %w", errors.Join(fErr, osErr))
}
22 changes: 19 additions & 3 deletions resolver/query_logging_resolver_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@ var _ = Describe("QueryLoggingResolver", func() {
var (
sut *QueryLoggingResolver
sutConfig config.QueryLog
err error
m *mockResolver
tmpDir *TmpFolder
mockRType ResponseType
Expand All @@ -61,8 +62,6 @@ var _ = Describe("QueryLoggingResolver", func() {
ctx, cancelFn = context.WithCancel(context.Background())
DeferCleanup(cancelFn)

var err error

sutConfig, err = config.WithDefaults[config.QueryLog]()
Expect(err).Should(Succeed())

Expand All @@ -76,7 +75,8 @@ var _ = Describe("QueryLoggingResolver", func() {
sutConfig.SetDefaults() // not called when using a struct literal
}

sut = NewQueryLoggingResolver(ctx, sutConfig)
sut, err = NewQueryLoggingResolver(ctx, sutConfig)
Expect(err).Should(Succeed())

m = &mockResolver{
ResolveFn: func(context.Context, *Request) (*Response, error) {
Expand Down Expand Up @@ -441,6 +441,22 @@ var _ = Describe("QueryLoggingResolver", func() {
})
})
})

Describe("Hostname function tests", func() {
It("should use the given file if it exists", func() {
expected := "TestName"
tmpFile := NewTmpFolder("hostname").CreateStringFile("filetest1", expected+" \n")

Expect(readInstanceID(tmpFile.Path)).Should(Equal(expected))
})

It("should fallback to os.Hostname", func() {
expected, err := os.Hostname()
Expect(err).Should(Succeed())

Expect(readInstanceID("/var/empty/nonexistent")).Should(Equal(expected))
})
})
})

func readCsv(file string) ([][]string, error) {
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4 changes: 3 additions & 1 deletion server/server.go
Original file line number Diff line number Diff line change
Expand Up @@ -304,12 +304,14 @@ func createQueryResolver(
upstreamTree, utErr := resolver.NewUpstreamTreeResolver(ctx, cfg.Upstreams, bootstrap)
blocking, blErr := resolver.NewBlockingResolver(ctx, cfg.Blocking, redisClient, bootstrap)
clientNames, cnErr := resolver.NewClientNamesResolver(ctx, cfg.ClientLookup, cfg.Upstreams, bootstrap)
queryLogging, qlErr := resolver.NewQueryLoggingResolver(ctx, cfg.QueryLog)
condUpstream, cuErr := resolver.NewConditionalUpstreamResolver(ctx, cfg.Conditional, cfg.Upstreams, bootstrap)
hostsFile, hfErr := resolver.NewHostsFileResolver(ctx, cfg.HostsFile, bootstrap)

err := multierror.Append(
multierror.Prefix(utErr, "upstream tree resolver: "),
multierror.Prefix(blErr, "blocking resolver: "),
multierror.Prefix(qlErr, "query logging resolver: "),
multierror.Prefix(cnErr, "client names resolver: "),
multierror.Prefix(cuErr, "conditional upstream resolver: "),
multierror.Prefix(hfErr, "hosts file resolver: "),
Expand All @@ -324,7 +326,7 @@ func createQueryResolver(
resolver.NewECSResolver(cfg.ECS),
clientNames,
resolver.NewEDEResolver(cfg.EDE),
resolver.NewQueryLoggingResolver(ctx, cfg.QueryLog),
queryLogging,
resolver.NewMetricsResolver(cfg.Prometheus),
resolver.NewRewriterResolver(cfg.CustomDNS.RewriterConfig, resolver.NewCustomDNSResolver(cfg.CustomDNS)),
hostsFile,
Expand Down
40 changes: 0 additions & 40 deletions util/hostname.go

This file was deleted.

48 changes: 0 additions & 48 deletions util/hostname_test.go

This file was deleted.

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