Fail loudly on an unparseable SENTRY_DSN and a malformed .env (closes #283)

cmd/webhooker/dotenv_test.go

@@ -0,0 +1,107 @@
+package main
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/webhooker/internal/config"
+)
+
+// dotEnvKey is a throwaway variable name these tests write and read,
+// so they cannot disturb real configuration.
+const dotEnvKey = "WEBHOOKER_TEST_DISPATCH_VALUE"
+
+// writeDotEnvInWorkingDir puts contents in a .env file in a fresh
+// temporary directory and moves the process there.
+//
+// The callers are deliberately not parallel and must stay that way:
+// t.Chdir moves the whole process. Go releases parallel tests only
+// after every sequential test in the package has finished, so nothing
+// else runs while these do.
+func writeDotEnvInWorkingDir(t *testing.T, contents string) {
+	t.Helper()
+
+	dir := t.TempDir()
+	require.NoError(t, os.WriteFile(
+		filepath.Join(dir, config.DotEnvPath),
+		[]byte(contents), 0o600,
+	))
+	t.Chdir(dir)
+}
+
+// TestDispatch_MalformedDotEnvRefuses pins the second half of the
+// defect. godotenv applies nothing at all when a file will not parse,
+// so one mistyped line used to revert every variable in it to its
+// default and start the server anyway, with no log line naming the
+// file. The refusal has to arrive before any subcommand runs, which
+// is why `help` — the one subcommand that touches nothing — is still
+// refused here.
+//
+//nolint:paralleltest // t.Chdir moves the whole process.
+func TestDispatch_MalformedDotEnvRefuses(t *testing.T) {
+	writeDotEnvInWorkingDir(t, "PORT 19615\n")
+
+	var stdout, stderr bytes.Buffer
+
+	code := dispatch(
+		[]string{helpCommand}, strings.NewReader(""), &stdout, &stderr,
+	)
+
+	require.Equal(t, 1, code, "a broken .env must exit non-zero")
+	assert.Contains(
+		t, stderr.String(), config.DotEnvPath,
+		"the refusal must name the file",
+	)
+	assert.Empty(
+		t, stdout.String(),
+		"the subcommand must not have run",
+	)
+}
+
+// TestDispatch_LoadsDotEnvBeforeSubcommands pins the ordering the
+// godotenv/autoload import used to provide for free. It ran in an
+// init(), so .env was in the environment before anything read it —
+// including config.DataDir, which both the DATA_DIR lock and resetpw
+// call outside the fx graph. Loading any later would let a .env that
+// sets DATA_DIR lock one directory while the config opened databases
+// in another.
+func TestDispatch_LoadsDotEnvBeforeSubcommands(t *testing.T) {
+	t.Setenv(dotEnvKey, "placeholder")
+	require.NoError(t, os.Unsetenv(dotEnvKey))
+
+	writeDotEnvInWorkingDir(t, dotEnvKey+"=from-dot-env\n")
+
+	var stdout, stderr bytes.Buffer
+
+	code := dispatch(
+		[]string{helpCommand}, strings.NewReader(""), &stdout, &stderr,
+	)
+
+	require.Equal(t, 0, code)
+	assert.Equal(
+		t, "from-dot-env", os.Getenv(dotEnvKey),
+		"the file must be applied before the subcommand runs",
+	)
+}
+
+// TestDispatch_MissingDotEnvIsFine pins the case most deployments are
+// in: no .env at all, which must stay a normal start.
+//
+//nolint:paralleltest // t.Chdir moves the whole process.
+func TestDispatch_MissingDotEnvIsFine(t *testing.T) {
+	t.Chdir(t.TempDir())
+
+	var stdout, stderr bytes.Buffer
+
+	code := dispatch(
+		[]string{helpCommand}, strings.NewReader(""), &stdout, &stderr,
+	)
+
+	require.Equal(t, 0, code)
+	assert.Empty(t, stderr.String())
+}

cmd/webhooker/main.go

@@ -54,6 +54,11 @@ const stopTimeout = 5 * time.Second
 // caller can tell "called wrong" from "declined".
 const exitUsage = 2
 
+// helpCommand is the subcommand that prints usage. The flag spellings
+// beside it in the switch are aliases; this is the name the usage text
+// documents and the one tests invoke.
+const helpCommand = "help"
+
 // Build-time variables set via -ldflags.
 //
 //nolint:gochecknoglobals // Build-time variables injected by the linker.
@@ -75,11 +80,27 @@ func main() {
 // every existing deployment invoke; that path is unchanged, including
 // where the DATA_DIR lock is taken relative to building the fx graph
 // and how fx propagates a non-zero exit itself.
+//
+// The optional .env file is read here, before any subcommand and so
+// before anything reads the environment — config.DataDir, which both
+// the DATA_DIR lock and resetpw call outside the fx graph, above all.
+// It used to be read from an init() in internal/config, which put it
+// earlier still but threw the error away: a single malformed line
+// applied none of the file and said nothing about it. A file that is
+// not there stays fine, since .env is optional and most deployments
+// do not have one.
 func dispatch(
 	args []string,
 	stdin io.Reader,
 	stdout, stderr io.Writer,
 ) int {
+	err := config.LoadDotEnv()
+	if err != nil {
+		_, _ = fmt.Fprintf(stderr, "%s: %v\n", appname, err)
+
+		return 1
+	}
+
 	if len(args) == 0 {
 		return run(stderr)
 	}
@@ -87,7 +108,7 @@ func dispatch(
 	switch args[0] {
 	case resetpw.Name:
 		return resetpw.Run(args[1:], stdin, stdout, stderr)
-	case "help", "-h", "-help", "--help":
+	case helpCommand, "-h", "-help", "--help":
 		usage(stdout)
 
 		return 0

cmd/webhooker/main_test.go

@@ -121,7 +121,7 @@ func TestDispatch_Help(t *testing.T) {
 	var stdout, stderr bytes.Buffer
 
 	code := dispatch(
-		[]string{"help"}, strings.NewReader(""), &stdout, &stderr,
+		[]string{helpCommand}, strings.NewReader(""), &stdout, &stderr,
 	)
 
 	require.Equal(t, 0, code)