refactor: move cel environment creation to a subpackage

Signed-off-by: Xe Iaso <me@xeiaso.net>

lib/checker/expression/checker.go

@@ -5,6 +5,7 @@ import (
 	"net/http"
 
 	"github.com/TecharoHQ/anubis/internal"
+	"github.com/TecharoHQ/anubis/lib/checker/expression/environment"
 	"github.com/TecharoHQ/anubis/lib/policy/expressions"
 	"github.com/google/cel-go/cel"
 	"github.com/google/cel-go/common/types"
@@ -17,12 +18,12 @@ type Checker struct {
 }
 
 func New(cfg *Config) (*Checker, error) {
-	env, err := expressions.BotEnvironment()
+	env, err := environment.Bot()
 	if err != nil {
 		return nil, err
 	}
 
-	program, err := expressions.Compile(env, cfg.String())
+	program, err := environment.Compile(env, cfg.String())
 	if err != nil {
 		return nil, fmt.Errorf("can't compile CEL program: %w", err)
 	}

lib/checker/expression/environment/environment.go

@@ -1,4 +1,4 @@
-package expressions
+package environment
 
 import (
 	"math/rand/v2"
@@ -10,11 +10,11 @@ import (
 	"github.com/google/cel-go/ext"
 )
 
-// BotEnvironment creates a new CEL environment, this is the set of
+// Bot creates a new CEL environment, this is the set of variables and
-// variables and functions that are passed into the CEL scope so that
+// functions that are passed into the CEL scope so that Anubis can fail
-// Anubis can fail loudly and early when something is invalid instead
+// loudly and early when something is invalid instead of blowing up at
-// of blowing up at runtime.
+// runtime.
-func BotEnvironment() (*cel.Env, error) {
+func Bot() (*cel.Env, error) {
 	return New(
 		// Variables exposed to CEL programs:
 		cel.Variable("remoteAddress", cel.StringType),
@@ -57,13 +57,14 @@ func BotEnvironment() (*cel.Env, error) {
 	)
 }
 
-// NewThreshold creates a new CEL environment for threshold checking.
+// Threshold creates a new CEL environment for threshold checking.
-func ThresholdEnvironment() (*cel.Env, error) {
+func Threshold() (*cel.Env, error) {
 	return New(
 		cel.Variable("weight", cel.IntType),
 	)
 }
 
+// New creates a new base CEL environment.
 func New(opts ...cel.EnvOption) (*cel.Env, error) {
 	args := []cel.EnvOption{
 		ext.Strings(
@@ -95,7 +96,7 @@ func New(opts ...cel.EnvOption) (*cel.Env, error) {
 	return cel.NewEnv(args...)
 }
 
-// Compile takes CEL environment and syntax tree then emits an optimized
+// Compile takes a CEL environment and syntax tree then emits an optimized
 // Program for execution.
 func Compile(env *cel.Env, src string) (cel.Program, error) {
 	intermediate, iss := env.Compile(src)

lib/checker/expression/environment/environment_test.go

@@ -1,4 +1,4 @@
-package expressions
+package environment
 
 import (
 	"testing"
@@ -6,8 +6,8 @@ import (
 	"github.com/google/cel-go/common/types"
 )
 
-func TestBotEnvironment(t *testing.T) {
+func TestBot(t *testing.T) {
-	env, err := BotEnvironment()
+	env, err := Bot()
 	if err != nil {
 		t.Fatalf("failed to create bot environment: %v", err)
 	}
@@ -108,8 +108,8 @@ func TestBotEnvironment(t *testing.T) {
 	})
 }
 
-func TestThresholdEnvironment(t *testing.T) {
+func TestThreshold(t *testing.T) {
-	env, err := ThresholdEnvironment()
+	env, err := Threshold()
 	if err != nil {
 		t.Fatalf("failed to create threshold environment: %v", err)
 	}