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feat(mcp): scaffold uses real EINHERJAR_SERVER_CORS_ORIGINS; document web.New vs server.New (v1.2.0)

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This commit is contained in:
Rene Nochebuena
2026-08-08 02:29:16 -06:00
parent 6b4d9be141
commit 03a8d8a641
6 changed files with 70 additions and 37 deletions
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internal/index/builtins/README.md
+29 -11
View File
@@ -102,15 +102,14 @@ type JWTConfig struct {
// are nested fields; caarlos0/env recurses into them, populating their
// EINHERJAR_SERVER_* / EINHERJAR_PG_* tags from the environment.
type Config struct {
AppEnv string `env:"APP_ENV" envDefault:"local"`
CORSOrigins []string `env:"APP_CORS_ORIGINS" envSeparator:","`
AppEnv string `env:"APP_ENV" envDefault:"local"`
JWT JWTConfig
// Framework component configs — composed verbatim. Their own EINHERJAR_* tags
// load through this one env.Parse call.
Log logz.Config // EINHERJAR_LOG_*
Server server.Config // EINHERJAR_SERVER_*
Server server.Config // EINHERJAR_SERVER_* (incl. EINHERJAR_SERVER_CORS_ORIGINS)
PG postgres.Config // EINHERJAR_PG_*
}
@@ -149,17 +148,16 @@ After you compose a component, run **`check_env`** with what the app composes: i
`EINHERJAR_*` names that don't exist, required vars you forgot to document, and vars set for a
config you don't actually compose (dead vars). Prefer the **`composes`** input (exact struct
selectors like `web/server/Config`) over `modules` — it catches struct-level dead vars (e.g.
`EINHERJAR_SERVER_CORS_ORIGINS` lives on `web.Config`, not `server.Config`). `get_scaffold` already
emits a `.env.example` derived from these same tags, so the starting point is correct by construction.
`EINHERJAR_HEALTH_CHECK_TIMEOUT` lives on `web/health.Config`, so it is dead if you compose
`web/server/Config` but not the health config). `get_scaffold` already emits a `.env.example`
derived from these same tags, so the starting point is correct by construction.
```bash
# .env.example — copy to .env for local dev. Every var the app reads lives here.
# ── App ───────────────────────────────────────────────────────────────────
APP_ENV=local
# APP_CORS_ORIGINS — explicit origins for non-local envs (comma-separated).
# Local uses mw.CORSAllowAll() and ignores this; "*" is rejected by mw.CORS — never use it.
APP_CORS_ORIGINS=
# CORS: local uses mw.CORSAllowAll(); non-local reads EINHERJAR_SERVER_CORS_ORIGINS (below).
APP_JWT_SECRET=change-me
APP_JWT_ISSUER=myapp
@@ -170,6 +168,9 @@ APP_JWT_ISSUER=myapp
# ── Einherjar: HTTP server (EINHERJAR_SERVER_*) ───────────────────────────
EINHERJAR_SERVER_HOST=0.0.0.0
EINHERJAR_SERVER_PORT=8080
# EINHERJAR_SERVER_CORS_ORIGINS — explicit origins for non-local envs (comma-separated).
# "*" is rejected by mw.CORS; local dev uses mw.CORSAllowAll() and ignores this.
# EINHERJAR_SERVER_CORS_ORIGINS=
# ── Einherjar: PostgreSQL (EINHERJAR_PG_*) ────────────────────────────────
EINHERJAR_PG_HOST=localhost
@@ -189,6 +190,22 @@ The application entry point. The order below is load-bearing: configuration firs
second, infrastructure third, cross-cutting helpers fourth, then the launcher with every component
appended, then feature hooks, then `lc.Run()`.
**`web.New` vs `server.New` — pick the right tier:**
- **`web.New(logger, web.Config{Server: cfg.Server})`** — batteries-included. It pre-wires the
recommended middleware stack (Recover → RequestID → RequestLogger) and applies `mw.CORS` from
`EINHERJAR_SERVER_CORS_ORIGINS` automatically (explicit origins only; empty ⇒ CORS off + a log
line). Use it for a plain service that just needs the defaults. It does **not** support allow-all
CORS or a custom middleware order.
- **`server.New(logger, cfg.Server, server.WithMiddleware(...))`** — full control. You compose the
middleware list yourself. Use it when you need a **custom middleware order**, extra middleware
(auth, enrichment), a custom request-ID generator, or **allow-all CORS in local dev**
(`mw.CORSAllowAll`, gated by `AppEnv` — see below). The starter below uses `server.New` precisely
because it inserts JWT auth + enrichment into the stack.
Whichever tier you pick, CORS origins always come from the framework var
`EINHERJAR_SERVER_CORS_ORIGINS` (`cfg.Server.CORSOrigins`) — never invent an app-owned CORS var.
```go
package wire
@@ -231,11 +248,12 @@ func Run() error {
db := postgres.New(logger, cfg.PG)
// CORS convention: allow-all in local dev, explicit origins everywhere else.
// mw.CORS panics on "*" (it matches no real origin) — allow-all is mw.CORSAllowAll,
// never a "*" in APP_CORS_ORIGINS.
// Origins come from the framework's own EINHERJAR_SERVER_CORS_ORIGINS
// (cfg.Server.CORSOrigins) — never invent an APP_CORS_ORIGINS var. mw.CORS panics
// on "*" (it matches no real origin) — allow-all is mw.CORSAllowAll, never a "*".
corsMW := mw.CORSAllowAll()
if !strings.EqualFold(cfg.AppEnv, "local") {
corsMW = mw.CORS(cfg.CORSOrigins)
corsMW = mw.CORS(cfg.Server.CORSOrigins)
}
srv := server.New(logger, cfg.Server,
internal/tools/env_tools_test.go
+16 -15
View File
@@ -30,7 +30,8 @@ func TestRenderEnvExample(t *testing.T) {
// Required, no default → uncommented with a runnable dev value.
mustContain := []string{
"APP_ENV=local",
"APP_CORS_ORIGINS=",
// CORS now lives on server.Config (composed) → documented, commented, no default.
"# EINHERJAR_SERVER_CORS_ORIGINS=",
"EINHERJAR_PG_HOST=localhost",
"EINHERJAR_PG_USER=postgres",
"EINHERJAR_PG_PASSWORD=postgres",
@@ -57,10 +58,10 @@ func TestRenderEnvExample(t *testing.T) {
mustNotContain := []string{
"EINHERJAR_PG_DATABASE",
"EINHERJAR_SERVER_ADDR",
"APP_CORS_ORIGINS=*", // the wildcard trap must never be emitted
// CORS lives on web.Config, which the scaffold does not compose — so it
// must not be emitted (it would be a dead var).
"EINHERJAR_SERVER_CORS_ORIGINS",
// APP_CORS_ORIGINS was an invented var — the scaffold now uses the real
// framework var (EINHERJAR_SERVER_CORS_ORIGINS on server.Config), so no
// form of APP_CORS_ORIGINS may ever be emitted.
"APP_CORS_ORIGINS",
}
for _, s := range mustNotContain {
if strings.Contains(got, s) {
@@ -164,36 +165,36 @@ func TestCheckEnvUnknownModule(t *testing.T) {
}
// TestCheckEnvStructLevel proves the struct-granularity path catches a dead var
// that module granularity cannot: EINHERJAR_SERVER_CORS_ORIGINS lives on
// web.Config, so an app composing web/server/Config (not web.Config) never reads
// it — module "web" would hide that, struct selectors surface it.
// that module granularity cannot: EINHERJAR_HEALTH_CHECK_TIMEOUT lives on
// web/health.Config, so an app composing web/server/Config (not web/health/Config)
// never reads it — module "web" would hide that, struct selectors surface it.
func TestCheckEnvStructLevel(t *testing.T) {
idx := loadRealIndex(t)
env := "EINHERJAR_SERVER_CORS_ORIGINS=*\nEINHERJAR_PG_HOST=h\nEINHERJAR_PG_USER=u\nEINHERJAR_PG_PASSWORD=p\nEINHERJAR_PG_NAME=n\n"
env := "EINHERJAR_HEALTH_CHECK_TIMEOUT=5s\nEINHERJAR_PG_HOST=h\nEINHERJAR_PG_USER=u\nEINHERJAR_PG_PASSWORD=p\nEINHERJAR_PG_NAME=n\n"
// struct-level: server/Config has no CORS → CORS flagged as dead.
// struct-level: server/Config has no health timeout → the var is flagged as dead.
structF, err := checkEnvVars(idx, env, nil, []string{"web/server/Config", "db-postgres/Config"})
if err != nil {
t.Fatal(err)
}
dead := false
for _, f := range structF {
if f.Kind == "not-composed" && f.Var == "EINHERJAR_SERVER_CORS_ORIGINS" {
if f.Kind == "not-composed" && f.Var == "EINHERJAR_HEALTH_CHECK_TIMEOUT" {
dead = true
}
}
if !dead {
t.Errorf("struct-level: expected EINHERJAR_SERVER_CORS_ORIGINS flagged not-composed; got %+v", structF)
t.Errorf("struct-level: expected EINHERJAR_HEALTH_CHECK_TIMEOUT flagged not-composed; got %+v", structF)
}
// module-level ["web"] keeps CORS silent (documents the coarse behavior).
// module-level ["web"] keeps it silent (health lives in module web).
modF, err := checkEnvVars(idx, env, []string{"web", "db-postgres"}, nil)
if err != nil {
t.Fatal(err)
}
for _, f := range modF {
if f.Var == "EINHERJAR_SERVER_CORS_ORIGINS" {
t.Errorf("module-level should not flag CORS (it lives in module web), got %+v", f)
if f.Var == "EINHERJAR_HEALTH_CHECK_TIMEOUT" {
t.Errorf("module-level should not flag the health timeout (it lives in module web), got %+v", f)
}
}
}
internal/tools/scaffold.go
+7 -9
View File
@@ -131,13 +131,14 @@ func Run() error {
db := postgres.New(logger, cfg.PG)
// CORS: allow-all in local dev; explicit origins elsewhere. mw.CORS panics on
// "*", so never pass a wildcard through APP_CORS_ORIGINS outside local.
// CORS: allow-all in local dev; explicit origins elsewhere. Origins come from the
// framework's own EINHERJAR_SERVER_CORS_ORIGINS (cfg.Server.CORSOrigins). mw.CORS
// panics on "*", so never set that var to a wildcard outside local.
var corsMW func(http.Handler) http.Handler
if strings.EqualFold(cfg.AppEnv, "local") {
corsMW = mw.CORSAllowAll()
} else {
corsMW = mw.CORS(cfg.CORSOrigins)
corsMW = mw.CORS(cfg.Server.CORSOrigins)
}
srv := server.New(logger, cfg.Server,
@@ -202,14 +203,13 @@ import (
// the nested framework configs, populating their EINHERJAR_* tags from the
// environment next to the app-owned APP_* fields.
type Config struct {
AppEnv string ` + "`" + `env:"APP_ENV" envDefault:"local"` + "`" + `
CORSOrigins []string ` + "`" + `env:"APP_CORS_ORIGINS" envSeparator:","` + "`" + `
AppEnv string ` + "`" + `env:"APP_ENV" envDefault:"local"` + "`" + `
// Framework component configs — composed verbatim; their EINHERJAR_* tags
// load through this same env.Parse call.
Launcher launcher.Config // EINHERJAR_COMPONENT_STOP_TIMEOUT
Log logz.Config // EINHERJAR_LOG_*
Server server.Config // EINHERJAR_SERVER_*
Server server.Config // EINHERJAR_SERVER_* (incl. EINHERJAR_SERVER_CORS_ORIGINS)
Health health.Config // EINHERJAR_HEALTH_CHECK_TIMEOUT
PG postgres.Config // EINHERJAR_PG_*
}
@@ -237,9 +237,7 @@ func renderEnvExample(idx *index.Index, app string) string {
b.WriteString("# ── App (APP_*) ────────────────────────────────────────────────────────────\n")
b.WriteString("APP_ENV=local\n")
b.WriteString("# APP_CORS_ORIGINS — explicit origins for non-local envs (comma-separated).\n")
b.WriteString("# Local uses mw.CORSAllowAll() and ignores this; \"*\" is rejected by mw.CORS — never use it.\n")
b.WriteString("APP_CORS_ORIGINS=\n\n")
b.WriteString("# CORS: local uses mw.CORSAllowAll(); non-local reads EINHERJAR_SERVER_CORS_ORIGINS below.\n\n")
writeEnvSection(&b, "Einherjar: launcher", envspec.FindStruct(idx, "core", "launcher", "Config"), app)
writeEnvSection(&b, "Einherjar: logging", envspec.FindStruct(idx, "core", "logz", "Config"), app)