feat: environment values and named environments (#53)

go.work.sum

@@ -321,10 +321,12 @@ github.com/segmentio/asm v1.2.1 h1:DTNbBqs57ioxAD4PrArqftgypG4/qNpXoJx8TVXxPR0=
 github.com/segmentio/asm v1.2.1/go.mod h1:BqMnlJP91P8d+4ibuonYZw9mfnzI9HfxselHZr5aAcs=
 github.com/shopspring/decimal v1.4.0 h1:bxl37RwXBklmTi0C79JfXCEBD1cqqHt0bbgBAGFp81k=
 github.com/shopspring/decimal v1.4.0/go.mod h1:gawqmDU56v4yIKSwfBSFip1HdCCXN8/+DMd9qYNcwME=
+github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
 github.com/spiffe/go-spiffe/v2 v2.6.0 h1:l+DolpxNWYgruGQVV0xsfeya3CsC7m8iBzDnMpsbLuo=
 github.com/spiffe/go-spiffe/v2 v2.6.0/go.mod h1:gm2SeUoMZEtpnzPNs2Csc0D/gX33k1xIx7lEzqblHEs=
 github.com/tursodatabase/libsql-client-go v0.0.0-20251219100830-236aa1ff8acc h1:lzi/5fg2EfinRlh3v//YyIhnc4tY7BTqazQGwb1ar+0=
 github.com/tursodatabase/libsql-client-go v0.0.0-20251219100830-236aa1ff8acc/go.mod h1:08inkKyguB6CGGssc/JzhmQWwBgFQBgjlYFjxjRh7nU=
+github.com/urfave/cli/v2 v2.3.0/go.mod h1:LJmUH05zAU44vOAcrfzZQKsZbVcdbOG8rtL3/XcUArI=
 github.com/vertica/vertica-sql-go v1.3.5 h1:IrfH2WIgzZ45yDHyjVFrXU2LuKNIjF5Nwi90a6cfgUI=
 github.com/vertica/vertica-sql-go v1.3.5/go.mod h1:jnn2GFuv+O2Jcjktb7zyc4Utlbu9YVqpHH/lx63+1M4=
 github.com/xhit/go-str2duration/v2 v2.1.0 h1:lxklc02Drh6ynqX+DdPyp5pCKLUQpRT8bp8Ydu2Bstc=
@@ -340,10 +342,7 @@ go.opencensus.io v0.24.0 h1:y73uSU6J157QMP2kn2r30vwW1A2W2WFwSCGnAVxeaD0=
 go.opencensus.io v0.24.0/go.mod h1:vNK8G9p7aAivkbmorf4v+7Hgx+Zs0yY+0fOtgBfjQKo=
 go.opentelemetry.io/contrib/detectors/gcp v1.39.0 h1:kWRNZMsfBHZ+uHjiH4y7Etn2FK26LAGkNFw7RHv1DhE=
 go.opentelemetry.io/contrib/detectors/gcp v1.39.0/go.mod h1:t/OGqzHBa5v6RHZwrDBJ2OirWc+4q/w2fTbLZwAKjTk=
-golang.org/x/mod v0.33.0 h1:tHFzIWbBifEmbwtGz65eaWyGiGZatSrT9prnU8DbVL8=
-golang.org/x/mod v0.33.0/go.mod h1:swjeQEj+6r7fODbD2cqrnje9PnziFuw4bmLbBZFrQ5w=
-golang.org/x/tools v0.42.0 h1:uNgphsn75Tdz5Ji2q36v/nsFSfR/9BRFvqhGBaJGd5k=
-golang.org/x/tools v0.42.0/go.mod h1:Ma6lCIwGZvHK6XtgbswSoWroEkhugApmsXyrUmBhfr0=
+golang.org/x/telemetry v0.0.0-20260209163413-e7419c687ee4/go.mod h1:g5NllXBEermZrmR51cJDQxmJUHUOfRAaNyWBM+R+548=
 golang.org/x/tools/go/expect v0.1.1-deprecated h1:jpBZDwmgPhXsKZC6WhL20P4b/wmnpsEAGHaNy0n/rJM=
 golang.org/x/tools/go/expect v0.1.1-deprecated/go.mod h1:eihoPOH+FgIqa3FpoTwguz/bVUSGBlGQU67vpBeOrBY=
 golang.org/x/tools/go/packages/packagestest v0.1.1-deprecated h1:1h2MnaIAIXISqTFKdENegdpAgUXz6NrPEsbIeWaBRvM=
@@ -355,3 +354,4 @@ google.golang.org/genproto/googleapis/bytestream v0.0.0-20250804133106-a7a43d27e
 google.golang.org/genproto/googleapis/bytestream v0.0.0-20250804133106-a7a43d27e69b/go.mod h1:h6yxum/C2qRb4txaZRLDHK8RyS0H/o2oEDeKY4onY/Y=
 howett.net/plist v1.0.1 h1:37GdZ8tP09Q35o9ych3ehygcsL+HqKSwzctveSlarvM=
 howett.net/plist v1.0.1/go.mod h1:lqaXoTrLY4hg8tnEzNru53gicrbv7rrk+2xJA/7hw9g=
+sigs.k8s.io/yaml v1.3.0/go.mod h1:GeOyir5tyXNByN85N/dRIT9es5UQNerPYEKK56eTBm8=

packages/engine/internal/api/health/health.go

@@ -17,6 +17,8 @@ type LivenessChecker interface {
 	Name() string
 }
 
+// HealthzHandler returns an HTTP handler that always responds 200 OK, used as
+// a liveness probe.
 func HealthzHandler() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
@@ -25,6 +27,9 @@ func HealthzHandler() http.HandlerFunc {
 	}
 }
 
+// ReadyzHandler returns an HTTP handler used as a readiness probe. It pings
+// the database and checks each LivenessChecker; it responds 503 if any check
+// fails.
 func ReadyzHandler(database *sql.DB, checkers ...LivenessChecker) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")

packages/engine/internal/cel/cel.go

@@ -29,6 +29,7 @@ const maxProgramCacheSize = 10000
 type Evaluator struct {
 	env          *cel.Env
 	configEnv    map[string]string      // config-sourced env values from mantle.yaml
+	valuesEnv    map[string]string      // values-file env overrides (between config and OS)
 	envCache     map[string]string      // cached, filtered environment variables
 	programMu    sync.Mutex
 	programCache map[string]cel.Program // expression string -> compiled cel.Program
@@ -51,7 +52,7 @@ func NewEvaluator() (*Evaluator, error) {
 	if err != nil {
 		return nil, fmt.Errorf("creating CEL environment: %w", err)
 	}
-	return &Evaluator{env: env, envCache: mergeEnvVars(nil), programCache: make(map[string]cel.Program)}, nil
+	return &Evaluator{env: env, envCache: mergeEnvVars(nil, nil), programCache: make(map[string]cel.Program)}, nil
 }
 
 // Eval evaluates a CEL expression and returns the result as a Go value.
@@ -229,24 +230,38 @@ func (e *Evaluator) resolveValue(v any, ctx *Context) (any, error) {
 // OS env vars take precedence over config values.
 func (e *Evaluator) SetConfigEnv(configEnv map[string]string) {
 	e.configEnv = configEnv
-	e.envCache = mergeEnvVars(configEnv)
+	e.envCache = mergeEnvVars(configEnv, e.valuesEnv)
+}
+
+// SetValuesEnv sets the values-file env overrides and rebuilds the env cache.
+// Values-file env sits between config env and MANTLE_ENV_* OS variables in
+// the precedence stack: config < values < MANTLE_ENV_*.
+func (e *Evaluator) SetValuesEnv(valuesEnv map[string]string) {
+	e.valuesEnv = valuesEnv
+	e.envCache = mergeEnvVars(e.configEnv, e.valuesEnv)
 }
 
 // mergeEnvVars builds the env map available to CEL expressions.
 // It starts with config-sourced values (from the env: section in mantle.yaml),
-// then overlays MANTLE_ENV_* environment variables (stripping the prefix).
-// When a key exists in both, the OS env var wins and an info log is emitted.
+// then overlays values-file overrides, then overlays MANTLE_ENV_* environment
+// variables (stripping the prefix). When a key exists in both config/values and
+// the OS env, the OS env var wins and an info log is emitted.
 // This prevents CEL expressions from reading sensitive variables like
 // MANTLE_ENCRYPTION_KEY, MANTLE_DATABASE_URL, or AWS_SECRET_ACCESS_KEY.
-func mergeEnvVars(configEnv map[string]string) map[string]string {
+func mergeEnvVars(configEnv map[string]string, valuesEnv map[string]string) map[string]string {
 	env := make(map[string]string)
 
-	// Start with config values.
+	// Layer 1: config values (lowest precedence).
 	for k, v := range configEnv {
 		env[k] = v
 	}
 
-	// Overlay MANTLE_ENV_* from OS environment (env var wins).
+	// Layer 2: values-file overrides.
+	for k, v := range valuesEnv {
+		env[k] = v
+	}
+
+	// Layer 3: MANTLE_ENV_* from OS environment (highest precedence).
 	const prefix = "MANTLE_ENV_"
 	for _, e := range os.Environ() {
 		parts := strings.SplitN(e, "=", 2)

packages/engine/internal/cel/cel_test.go

@@ -303,7 +303,7 @@ func TestEnvVars_PrefixStripping(t *testing.T) {
 	os.Setenv("MANTLE_DATABASE_URL", "should-not-appear")
 	defer os.Unsetenv("MANTLE_DATABASE_URL")
 
-	result := mergeEnvVars(nil)
+	result := mergeEnvVars(nil, nil)
 
 	if v, ok := result["TEST_KEY"]; !ok || v != "test-value" {
 		t.Errorf("mergeEnvVars()[TEST_KEY] = %q, %v; want %q, true", v, ok, "test-value")

packages/engine/internal/cel/cel_values_test.go

@@ -0,0 +1,113 @@
+package cel
+
+import (
+	"testing"
+)
+
+func TestSetValuesEnv_LayersBetweenConfigAndOS(t *testing.T) {
+	eval, err := NewEvaluator()
+	if err != nil {
+		t.Fatalf("NewEvaluator() error: %v", err)
+	}
+
+	eval.SetConfigEnv(map[string]string{
+		"LOG_LEVEL": "info",
+		"REGION":    "us-west-2",
+		"APP_NAME":  "config-app",
+	})
+
+	eval.SetValuesEnv(map[string]string{
+		"LOG_LEVEL": "error",
+		"DB_HOST":   "prod-db.example.com",
+	})
+
+	ctx := &Context{
+		Steps:  make(map[string]map[string]any),
+		Inputs: make(map[string]any),
+	}
+
+	// Values override config.
+	result, err := eval.Eval(`env.LOG_LEVEL`, ctx)
+	if err != nil {
+		t.Fatalf("Eval(env.LOG_LEVEL) error: %v", err)
+	}
+	if result != "error" {
+		t.Errorf("env.LOG_LEVEL = %v, want %q (values overrides config)", result, "error")
+	}
+
+	// Config value preserved when values doesn't override.
+	result, err = eval.Eval(`env.REGION`, ctx)
+	if err != nil {
+		t.Fatalf("Eval(env.REGION) error: %v", err)
+	}
+	if result != "us-west-2" {
+		t.Errorf("env.REGION = %v, want %q (config preserved)", result, "us-west-2")
+	}
+
+	// Values-only key is accessible.
+	result, err = eval.Eval(`env.DB_HOST`, ctx)
+	if err != nil {
+		t.Fatalf("Eval(env.DB_HOST) error: %v", err)
+	}
+	if result != "prod-db.example.com" {
+		t.Errorf("env.DB_HOST = %v, want %q", result, "prod-db.example.com")
+	}
+}
+
+func TestSetValuesEnv_OSEnvTakesPrecedence(t *testing.T) {
+	eval, err := NewEvaluator()
+	if err != nil {
+		t.Fatalf("NewEvaluator() error: %v", err)
+	}
+
+	t.Setenv("MANTLE_ENV_LOG_LEVEL", "debug")
+
+	eval.SetConfigEnv(map[string]string{
+		"LOG_LEVEL": "info",
+	})
+	eval.SetValuesEnv(map[string]string{
+		"LOG_LEVEL": "error",
+	})
+
+	ctx := &Context{
+		Steps:  make(map[string]map[string]any),
+		Inputs: make(map[string]any),
+	}
+
+	result, err := eval.Eval(`env.LOG_LEVEL`, ctx)
+	if err != nil {
+		t.Fatalf("Eval(env.LOG_LEVEL) error: %v", err)
+	}
+	if result != "debug" {
+		t.Errorf("env.LOG_LEVEL = %v, want %q (OS env wins)", result, "debug")
+	}
+}
+
+func TestSetValuesEnv_NilClearsValuesLayer(t *testing.T) {
+	eval, err := NewEvaluator()
+	if err != nil {
+		t.Fatalf("NewEvaluator() error: %v", err)
+	}
+
+	eval.SetConfigEnv(map[string]string{
+		"LOG_LEVEL": "info",
+	})
+	eval.SetValuesEnv(map[string]string{
+		"LOG_LEVEL": "error",
+	})
+
+	eval.SetValuesEnv(nil)
+
+	ctx := &Context{
+		Steps:  make(map[string]map[string]any),
+		Inputs: make(map[string]any),
+	}
+
+	result, err := eval.Eval(`env.LOG_LEVEL`, ctx)
+	if err != nil {
+		t.Fatalf("Eval(env.LOG_LEVEL) error: %v", err)
+	}
+	if result != "info" {
+		t.Errorf("env.LOG_LEVEL = %v, want %q (back to config after clear)", result, "info")
+	}
+}

packages/engine/internal/cli/credentials.go

@@ -15,6 +15,7 @@ const (
 	CredTypeOIDC   = "oidc"
 )
 
+// Credentials holds the authentication material persisted to disk.
 type Credentials struct {
 	Type         string    `json:"type"`
 	APIKey       string    `json:"api_key,omitempty"`
@@ -23,11 +24,15 @@ type Credentials struct {
 	ExpiresAt    time.Time `json:"expires_at,omitempty"`
 }
 
+// DefaultCredentialsPath returns ~/.mantle/credentials, the default location
+// where authentication material is stored.
 func DefaultCredentialsPath() string {
 	home, _ := os.UserHomeDir()
 	return filepath.Join(home, ".mantle", "credentials")
 }
 
+// SaveCredentials marshals cred to JSON and writes it to path with
+// 0600 permissions, creating parent directories as needed.
 func SaveCredentials(path string, cred *Credentials) error {
 	if err := os.MkdirAll(filepath.Dir(path), 0700); err != nil {
 		return fmt.Errorf("creating credentials directory: %w", err)
@@ -42,6 +47,7 @@ func SaveCredentials(path string, cred *Credentials) error {
 	return nil
 }
 
+// LoadCredentials reads and parses the JSON credentials file at path.
 func LoadCredentials(path string) (*Credentials, error) {
 	data, err := os.ReadFile(path)
 	if err != nil {
@@ -54,6 +60,8 @@ func LoadCredentials(path string) (*Credentials, error) {
 	return &cred, nil
 }
 
+// DeleteCredentials removes the credentials file at path. It is not an error
+// if the file does not exist.
 func DeleteCredentials(path string) error {
 	if err := os.Remove(path); err != nil && !os.IsNotExist(err) {
 		return fmt.Errorf("removing credentials: %w", err)