Send fx's own events through the service's logger (closes #183) #443

Merged
clawbot merged 1 commits from issue-183-fx-logger into next 2026-10-02 17:22:06 +02:00
7 changed files with 238 additions and 40 deletions
+19 -14
View File
@@ -557,8 +557,8 @@ If it is lost, run `webhooker resetpw admin` on a stopped deployment.
```
It is a banner rather than a log line because that is the only time it
is ever shown: as one `INFO` record it sat among the roughly 45 fx
`PROVIDE`/`RUN`/`HOOK` lines a boot writes, and under `docker run -d`
is ever shown: as one `INFO` record it would sit among the records fx
writes as each start hook runs, and under `docker run -d`
it is one line in a log subject to rotation. The database stores only
its Argon2id hash. There is no second account and no forgot-password
flow, so the banner and the reset command below are the only two ways
@@ -628,7 +628,8 @@ Changing a password you still know needs none of this — use
`DEBUG=true` lowers the log level to `DEBUG`, which turns on every
statement GORM runs, the two by-design lookup misses on the
unauthenticated routes, and the rate limiter's own rejections. It is
unauthenticated routes, the rate limiter's own rejections, and fx's
records of building the dependency graph at startup. It is
meant to be safe to turn on while diagnosing a live service and safe to
paste the output of into a bug report.
@@ -2637,16 +2638,20 @@ read as more than it is:
that type on a specific webhook, and each line it writes is bounded
per event by the 1 MB receiver body cap. Adding one is a decision to
spend log volume on that webhook's payloads.
- **Two writers that do not go through `internal/logger` at all**, both
on standard error. `fx` prints the dependency graph and the lifecycle
hooks through its default console logger at startup and shutdown —
nothing calls `fx.WithLogger`, and `fx.New` builds that logger over
`os.Stderr`. The Go runtime writes a panic or a fatal error itself; a
panic in a background worker rather than in a request handler is the
case that reaches it, since nothing recovers those. Neither carries a
client-chosen value at a client-chosen length: the five `panic` calls
in this service are invariant guards over constants and over
`crypto/rand`.
- **The Go runtime**, which does not go through `internal/logger`. The
runtime writes an unrecovered panic or a fatal error itself, as plain
text on standard error, and that output cannot be redirected. A panic
in a background worker rather than in a request handler is the case
that reaches it, since nothing recovers those. It carries no
client-chosen value at a client-chosen length: the service's own
`panic` calls are invariant guards over constants and over
`crypto/rand`, apart from the one that hands `http.ErrAbortHandler`
back to `net/http`, described below.
- **A failure before fx's logger is built**, such as an invalid
configuration value. fx's logger takes the configuration, so when
that fails fx's own console logger still prints the failure as plain
text on standard error. Its values come from the operator's
environment, not from a client.
- **`net/http`'s own faults**, which are _not_ a separate writer.
`internal/server/http.go` builds its server with a nil `ErrorLog`, so
`net/http` falls back to the `log` package's default logger — and
@@ -2996,7 +3001,7 @@ webhooker/
│ ├── lifecycle/
│ │ └── lifecycle.go # Shared stop-hook waiter, bounded by the stop context
│ ├── logger/
│ │ └── logger.go # slog setup with TTY detection
│ │ └── logger.go # slog setup with TTY detection; fx's event logger
│ ├── metrics/
│ │ └── metrics.go # Delivery Prometheus collectors, labelled by target type
│ ├── middleware/
+14
View File
@@ -8,6 +8,7 @@ import (
"time"
"go.uber.org/fx"
"go.uber.org/fx/fxevent"
"sneak.berlin/go/webhooker/internal/config"
"sneak.berlin/go/webhooker/internal/database"
"sneak.berlin/go/webhooker/internal/datadir"
@@ -168,6 +169,19 @@ func run(stderr io.Writer) int {
func newApp() *fx.App {
return fx.New(
fx.StopTimeout(stopTimeout),
// fx's own events go through the service's logger, not fx's
// console logger on standard error. The exception is a failure
// before this logger is built, such as an invalid configuration
// value, which fx's console logger still prints there. fx holds
// its events back until this logger is built and then replays
// them, so it takes the configuration, which sets the level
// DEBUG=true asks for: without it the replay would run at INFO
// and drop every record of how the graph was built.
fx.WithLogger(
func(l *logger.Logger, _ *config.Config) fxevent.Logger {
return logger.NewFxLogger(l.Get())
},
),
fx.Provide(
globals.New,
logger.New,
+99
View File
@@ -2,6 +2,12 @@ package main
import (
"bytes"
"encoding/json"
"io"
"log/slog"
"net"
"os"
"strconv"
"strings"
"testing"
"time"
@@ -38,6 +44,99 @@ func TestNewApp_StopTimeout(t *testing.T) {
require.Less(t, got, dockerStopGrace)
}
// freePort returns a loopback TCP port that was free a moment ago, by
// taking one and releasing it.
func freePort(t *testing.T) int {
t.Helper()
var listenCfg net.ListenConfig
l, err := listenCfg.Listen(t.Context(), "tcp", "127.0.0.1:0")
require.NoError(t, err)
addr, ok := l.Addr().(*net.TCPAddr)
require.True(t, ok, "listener is not TCP")
require.NoError(t, l.Close())
return addr.Port
}
// TestNewApp_SendsFxEventsToTheLogger starts and stops the app main
// runs, with DEBUG=true, and reads back what reached the service's
// logger. fx's own events must arrive there as structured records:
// the start at INFO, and at DEBUG the records of how the graph was
// built.
//
// fx holds its events back until its logger is built and then replays
// them all at once, so the earliest of them arriving shows the replay
// ran at DEBUG: that globals.New was provided, which fx records before
// anything is built, and the run of logger.New, which happens before
// the configuration sets the level.
func TestNewApp_SendsFxEventsToTheLogger(t *testing.T) {
t.Setenv("DATA_DIR", t.TempDir())
t.Setenv("PORT", strconv.Itoa(freePort(t)))
t.Setenv("DEBUG", "true")
// internal/logger writes to whatever os.Stdout is when it builds
// its handler. A file is not a terminal, so that handler is the
// JSON one the service uses in production.
out, err := os.CreateTemp(t.TempDir(), "stdout")
require.NoError(t, err)
stdout := os.Stdout
os.Stdout = out
t.Cleanup(func() {
os.Stdout = stdout
_ = out.Close()
})
app := newApp()
require.NoError(t, app.Start(t.Context()))
require.NoError(t, app.Stop(t.Context()))
_, err = out.Seek(0, io.SeekStart)
require.NoError(t, err)
written, err := io.ReadAll(out)
require.NoError(t, err)
type record struct {
Level string `json:"level"`
Msg string `json:"msg"`
Name string `json:"name"`
Constructor string `json:"constructor"`
}
var records []record
for line := range strings.Lines(string(written)) {
var r record
// The first-boot banner is plain text, not a record.
if json.Unmarshal([]byte(line), &r) == nil {
records = append(records, r)
}
}
const pkg = "sneak.berlin/go/webhooker/internal/"
info := slog.LevelInfo.String()
debug := slog.LevelDebug.String()
assert.Contains(t, records, record{Level: info, Msg: "started"})
assert.Contains(t, records, record{
Level: debug, Msg: "provided", Constructor: pkg + "globals.New()",
})
assert.Contains(t, records, record{
Level: debug, Msg: "run", Name: pkg + "logger.New()",
})
assert.Contains(t, records, record{Level: debug, Msg: "invoking"})
assert.Contains(t, records, record{
Level: debug, Msg: "initialized custom fxevent.Logger",
})
}
// TestRunRefusesLockedDataDir pins what an operator's second start
// does. The entry point must refuse before it builds the fx graph —
// nothing may open a database in a DATA_DIR another process holds —
+4 -6
View File
@@ -20,7 +20,7 @@ require (
github.com/prometheus/client_model v0.5.0
github.com/slok/go-http-metrics v0.11.0
github.com/stretchr/testify v1.11.1
go.uber.org/fx v1.20.1
go.uber.org/fx v1.24.0
golang.org/x/crypto v0.38.0
gopkg.in/yaml.v3 v3.0.1
gorm.io/driver/sqlite v1.5.4
@@ -42,7 +42,6 @@ require (
github.com/jinzhu/now v1.1.5 // indirect
github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51 // indirect
github.com/klauspost/cpuid/v2 v2.2.10 // indirect
github.com/kr/text v0.2.0 // indirect
github.com/mattn/go-isatty v0.0.20 // indirect
github.com/mattn/go-sqlite3 v1.14.17 // indirect
github.com/matttproud/golang_protobuf_extensions/v2 v2.0.0 // indirect
@@ -51,10 +50,9 @@ require (
github.com/prometheus/procfs v0.12.0 // indirect
github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
github.com/zeebo/xxh3 v1.0.2 // indirect
go.uber.org/atomic v1.9.0 // indirect
go.uber.org/dig v1.17.0 // indirect
go.uber.org/multierr v1.9.0 // indirect
go.uber.org/zap v1.23.0 // indirect
go.uber.org/dig v1.19.0 // indirect
go.uber.org/multierr v1.10.0 // indirect
go.uber.org/zap v1.26.0 // indirect
golang.org/x/mod v0.17.0 // indirect
golang.org/x/sync v0.14.0 // indirect
golang.org/x/sys v0.47.0 // indirect
+10 -20
View File
@@ -1,7 +1,5 @@
github.com/99designs/basicauth-go v0.0.0-20230316000542-bf6f9cbbf0f8 h1:nMpu1t4amK3vJWBibQ5X/Nv0aXL+b69TQf2uK5PH7Go=
github.com/99designs/basicauth-go v0.0.0-20230316000542-bf6f9cbbf0f8/go.mod h1:3cARGAK9CfW3HoxCy1a0G4TKrdiKke8ftOMEOHyySYs=
github.com/benbjohnson/clock v1.3.0 h1:ip6w0uFQkncKQ979AypyG0ER7mqUSBdKLOgAle/AT8A=
github.com/benbjohnson/clock v1.3.0/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
@@ -12,9 +10,6 @@ github.com/chromedp/chromedp v0.16.0 h1:rOO4deOm4CbZgBCa8mD9g2rDyIoNs0BkgvNrlbp5
github.com/chromedp/chromedp v0.16.0/go.mod h1:rbuGKFT1vMcFcFqKfPIO1GpX/N+2s8onm2qMxZLbU5U=
github.com/chromedp/sysutil v1.1.0 h1:PUFNv5EcprjqXZD9nJb9b/c9ibAbxiYo4exNWZyipwM=
github.com/chromedp/sysutil v1.1.0/go.mod h1:WiThHUdltqCNKGc4gaU50XgYjwjYIhKWoHGPTUfWTJ8=
github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
@@ -83,7 +78,6 @@ github.com/pingcap/errors v0.11.4 h1:lFuQV/oaUMGcD2tqt+01ROSmJs75VG1ToEOkZIZ4nE4
github.com/pingcap/errors v0.11.4/go.mod h1:Oi8TUi2kEtXXLMJk9l1cGmz20kV3TaQ0usTwv5KuLY8=
github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/prometheus/client_golang v1.18.0 h1:HzFfmkOzH5Q8L8G+kSJKUx5dtG87sewO+FoDDqP5Tbk=
@@ -100,28 +94,24 @@ github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjR
github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
github.com/slok/go-http-metrics v0.11.0 h1:ABJUpekCZSkQT1wQrFvS4kGbhea/w6ndFJaWJeh3zL0=
github.com/slok/go-http-metrics v0.11.0/go.mod h1:ZGKeYG1ET6TEJpQx18BqAJAvxw9jBAZXCHU7bWQqqAc=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/objx v0.5.2 h1:xuMeJ0Sdp5ZMRXx/aWO6RZxdr3beISkG5/G/aIRr3pY=
github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/8L+MA=
github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
github.com/zeebo/assert v1.3.0 h1:g7C04CbJuIDKNPFHmsk4hwZDO5O+kntRxzaUoNXj+IQ=
github.com/zeebo/assert v1.3.0/go.mod h1:Pq9JiuJQpG8JLJdtkwrJESF0Foym2/D9XMU5ciN/wJ0=
github.com/zeebo/xxh3 v1.0.2 h1:xZmwmqxHZA8AI603jOQ0tMqmBr9lPeFwGg6d+xy9DC0=
github.com/zeebo/xxh3 v1.0.2/go.mod h1:5NWz9Sef7zIDm2JHfFlcQvNekmcEl9ekUZQQKCYaDcA=
go.uber.org/atomic v1.9.0 h1:ECmE8Bn/WFTYwEW/bpKD3M8VtR/zQVbavAoalC1PYyE=
go.uber.org/atomic v1.9.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
go.uber.org/dig v1.17.0 h1:5Chju+tUvcC+N7N6EV08BJz41UZuO3BmHcN4A287ZLI=
go.uber.org/dig v1.17.0/go.mod h1:rTxpf7l5I0eBTlE6/9RL+lDybC7WFwY2QH55ZSjy1mU=
go.uber.org/fx v1.20.1 h1:zVwVQGS8zYvhh9Xxcu4w1M6ESyeMzebzj2NbSayZ4Mk=
go.uber.org/fx v1.20.1/go.mod h1:iSYNbHf2y55acNCwCXKx7LbWb5WG1Bnue5RDXz1OREg=
go.uber.org/goleak v1.1.11 h1:wy28qYRKZgnJTxGxvye5/wgWr1EKjmUDGYox5mGlRlI=
go.uber.org/goleak v1.1.11/go.mod h1:cwTWslyiVhfpKIDGSZEM2HlOvcqm+tG4zioyIeLoqMQ=
go.uber.org/multierr v1.9.0 h1:7fIwc/ZtS0q++VgcfqFDxSBZVv/Xo49/SYnDFupUwlI=
go.uber.org/multierr v1.9.0/go.mod h1:X2jQV1h+kxSjClGpnseKVIxpmcjrj7MNnI0bnlfKTVQ=
go.uber.org/zap v1.23.0 h1:OjGQ5KQDEUawVHxNwQgPpiypGHOxo2mNZsOqTak4fFY=
go.uber.org/zap v1.23.0/go.mod h1:D+nX8jyLsMHMYrln8A0rJjFt/T/9/bGgIhAqxv5URuY=
go.uber.org/dig v1.19.0 h1:BACLhebsYdpQ7IROQ1AGPjrXcP5dF80U3gKoFzbaq/4=
go.uber.org/dig v1.19.0/go.mod h1:Us0rSJiThwCv2GteUN0Q7OKvU7n5J4dxZ9JKUXozFdE=
go.uber.org/fx v1.24.0 h1:wE8mruvpg2kiiL1Vqd0CC+tr0/24XIB10Iwp2lLWzkg=
go.uber.org/fx v1.24.0/go.mod h1:AmDeGyS+ZARGKM4tlH4FY2Jr63VjbEDJHtqXTGP5hbo=
go.uber.org/goleak v1.2.0 h1:xqgm/S+aQvhWFTtR0XK3Jvg7z8kGV8P4X14IzwN3Eqk=
go.uber.org/goleak v1.2.0/go.mod h1:XJYK+MuIchqpmGmUSAzotztawfKvYLUIgg7guXrwVUo=
go.uber.org/multierr v1.10.0 h1:S0h4aNzvfcFsC3dRF1jLoaov7oRaKqRGC/pUEJ2yvPQ=
go.uber.org/multierr v1.10.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
go.uber.org/zap v1.26.0 h1:sI7k6L95XOKS281NhVKOFCUNIvv9e0w4BF8N3u+tCRo=
go.uber.org/zap v1.26.0/go.mod h1:dtElttAiwGvoJ/vj4IwHBS/gXsEu/pZ50mUIRWuG0so=
golang.org/x/crypto v0.38.0 h1:jt+WWG8IZlBnVbomuhg2Mdq0+BBQaHbtqHEFEigjUV8=
golang.org/x/crypto v0.38.0/go.mod h1:MvrbAqul58NNYPKnOra203SB9vpuZW0e+RRZV+Ggqjw=
golang.org/x/mod v0.17.0 h1:zY54UmvipHiNd+pm+m0x9KhZ9hl1/7QNMyxXbc6ICqA=
+38
View File
@@ -9,6 +9,7 @@ import (
"time"
"go.uber.org/fx"
"go.uber.org/fx/fxevent"
"sneak.berlin/go/webhooker/internal/globals"
)
@@ -106,3 +107,40 @@ func (l *Logger) Identify() {
func (l *Logger) Writer() io.Writer {
return os.Stdout
}
// FxLogger writes fx's own events through a slog logger: how the
// dependency graph was built at DEBUG, since it repeats on every
// start; the start and stop hooks, the start itself and the signal
// that stops the service at INFO; every failure at ERROR.
//
// The formatting is fx's own fxevent.SlogLogger. That logger takes a
// single level for every event that is not a failure, so FxLogger
// holds one at each level and picks between them.
type FxLogger struct {
graph *fxevent.SlogLogger
lifecycle *fxevent.SlogLogger
}
// NewFxLogger returns an FxLogger that writes through log.
func NewFxLogger(log *slog.Logger) *FxLogger {
graph := &fxevent.SlogLogger{Logger: log}
graph.UseLogLevel(slog.LevelDebug)
lifecycle := &fxevent.SlogLogger{Logger: log}
lifecycle.UseLogLevel(slog.LevelInfo)
return &FxLogger{graph: graph, lifecycle: lifecycle}
}
// LogEvent implements fxevent.Logger.
func (f *FxLogger) LogEvent(event fxevent.Event) {
switch event.(type) {
case *fxevent.Supplied, *fxevent.Provided, *fxevent.Replaced,
*fxevent.Decorated, *fxevent.BeforeRun, *fxevent.Run,
*fxevent.Invoking, *fxevent.Invoked,
*fxevent.LoggerInitialized:
f.graph.LogEvent(event)
default:
f.lifecycle.LogEvent(event)
}
}
+54
View File
@@ -1,13 +1,23 @@
package logger_test
import (
"bytes"
"encoding/json"
"errors"
"log/slog"
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"go.uber.org/fx"
"go.uber.org/fx/fxevent"
"go.uber.org/fx/fxtest"
"sneak.berlin/go/webhooker/internal/globals"
"sneak.berlin/go/webhooker/internal/logger"
)
var errStopHook = errors.New("stop hook failed on purpose")
func testGlobals() *globals.Globals {
return &globals.Globals{
Appname: "test-app",
@@ -57,3 +67,47 @@ func TestEnableDebugLogging(t *testing.T) {
// Test debug logging
l.Get().Debug("debug message", "test", true)
}
// TestFxLogger_Levels starts and stops an fx app that reports its own
// events through NewFxLogger, as cmd/webhooker does, and reads back
// what reached the handler: the graph at DEBUG, the start at INFO and
// a failed stop hook at ERROR, each as a structured record.
func TestFxLogger_Levels(t *testing.T) {
t.Parallel()
var out bytes.Buffer
log := slog.New(slog.NewJSONHandler(
&out, &slog.HandlerOptions{Level: slog.LevelDebug},
))
app := fx.New(
fx.WithLogger(func() fxevent.Logger {
return logger.NewFxLogger(log)
}),
fx.Invoke(func(lc fx.Lifecycle) {
lc.Append(fx.StopHook(func() error { return errStopHook }))
}),
)
require.NoError(t, app.Start(t.Context()))
require.ErrorIs(t, app.Stop(t.Context()), errStopHook)
levels := map[string]string{}
decoder := json.NewDecoder(&out)
for decoder.More() {
var record struct {
Level string `json:"level"`
Msg string `json:"msg"`
}
require.NoError(t, decoder.Decode(&record))
levels[record.Msg] = record.Level
}
assert.Equal(t, "DEBUG", levels["provided"])
assert.Equal(t, "INFO", levels["started"])
assert.Equal(t, "ERROR", levels["OnStop hook failed"])
}