feat: export external data default send request function (#205)

constraint/pkg/client/drivers/local/args.go

@@ -43,6 +43,10 @@ func Defaults() Arg {
 			d.compilers.capabilities.Builtins = append(d.compilers.capabilities.Builtins, newBuiltin)
 		}
 
+		if d.sendRequestToProvider == nil {
+			d.sendRequestToProvider = externaldata.DefaultSendRequestToProvider
+		}
+
 		return nil
 	}
 }

constraint/pkg/client/drivers/local/builtin.go

@@ -1,12 +1,7 @@
 package local
 
 import (
-	"bytes"
-	"context"
-	"encoding/json"
-	"io/ioutil"
 	"net/http"
-	"time"
 
 	"github.com/open-policy-agent/frameworks/constraint/pkg/externaldata"
 	"github.com/open-policy-agent/opa/ast"
@@ -25,41 +20,12 @@ func externalDataBuiltin(d *Driver) func(bctx rego.BuiltinContext, regorequest *
 			return externaldata.HandleError(http.StatusBadRequest, err)
 		}
 
-		externaldataRequest := externaldata.NewProviderRequest(regoReq.Keys)
-		reqBody, err := json.Marshal(externaldataRequest)
+		externaldataResponse, statusCode, err := d.sendRequestToProvider(bctx.Context, &provider, regoReq.Keys)
 		if err != nil {
-			return externaldata.HandleError(http.StatusInternalServerError, err)
+			return externaldata.HandleError(statusCode, err)
 		}
 
-		req, err := http.NewRequest("POST", provider.Spec.URL, bytes.NewBuffer(reqBody))
-		if err != nil {
-			return externaldata.HandleError(http.StatusInternalServerError, err)
-		}
-		req.Header.Set("Content-Type", "application/json")
-
-		ctx, cancel := context.WithDeadline(bctx.Context, time.Now().Add(time.Duration(provider.Spec.Timeout)*time.Second))
-		defer cancel()
-
-		resp, err := http.DefaultClient.Do(req.WithContext(ctx))
-		if err != nil {
-			return externaldata.HandleError(http.StatusInternalServerError, err)
-		}
-
-		defer func() {
-			_ = resp.Body.Close()
-		}()
-
-		respBody, err := ioutil.ReadAll(resp.Body)
-		if err != nil {
-			return externaldata.HandleError(http.StatusInternalServerError, err)
-		}
-
-		var externaldataResponse externaldata.ProviderResponse
-		if err := json.Unmarshal(respBody, &externaldataResponse); err != nil {
-			return externaldata.HandleError(http.StatusInternalServerError, err)
-		}
-
-		regoResponse := externaldata.NewRegoResponse(resp.StatusCode, &externaldataResponse)
+		regoResponse := externaldata.NewRegoResponse(statusCode, externaldataResponse)
 		return externaldata.PrepareRegoResponse(regoResponse)
 	}
 }

constraint/pkg/client/drivers/local/driver.go

@@ -58,6 +58,9 @@ type Driver struct {
 
 	// providerCache allows Rego to read from external_data in Rego queries.
 	providerCache *externaldata.ProviderCache
+
+	// sendRequestToProvider allows Rego to send requests to the provider specified in external_data.
+	sendRequestToProvider externaldata.SendRequestToProvider
 }
 
 // AddTemplate adds templ to Driver. Normalizes modules into usable forms for

constraint/pkg/externaldata/request.go

@@ -1,5 +1,17 @@
 package externaldata
 
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"time"
+
+	"github.com/open-policy-agent/frameworks/constraint/pkg/apis/externaldata/v1alpha1"
+)
+
 // RegoRequest is the request for external_data rego function.
 type RegoRequest struct {
 	// ProviderName is the name of the external data provider.
@@ -35,6 +47,45 @@ func NewProviderRequest(keys []string) *ProviderRequest {
 	}
 }
 
+// SendRequestToProvider is a function that sends a request to the external data provider.
+type SendRequestToProvider func(ctx context.Context, provider *v1alpha1.Provider, keys []string) (*ProviderResponse, int, error)
+
+// DefaultSendRequestToProvider is the default function to send the request to the external data provider.
+func DefaultSendRequestToProvider(ctx context.Context, provider *v1alpha1.Provider, keys []string) (*ProviderResponse, int, error) {
+	externaldataRequest := NewProviderRequest(keys)
+	body, err := json.Marshal(externaldataRequest)
+	if err != nil {
+		return nil, http.StatusInternalServerError, fmt.Errorf("failed to marshal external data request: %w", err)
+	}
+
+	req, err := http.NewRequest(http.MethodPost, provider.Spec.URL, bytes.NewBuffer(body))
+	if err != nil {
+		return nil, http.StatusInternalServerError, fmt.Errorf("failed to create external data request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	ctxWithDeadline, cancel := context.WithDeadline(ctx, time.Now().Add(time.Duration(provider.Spec.Timeout)*time.Second))
+	defer cancel()
+
+	resp, err := http.DefaultClient.Do(req.WithContext(ctxWithDeadline))
+	if err != nil {
+		return nil, http.StatusInternalServerError, fmt.Errorf("failed to send external data request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	respBody, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, http.StatusInternalServerError, fmt.Errorf("failed to read external data response: %w", err)
+	}
+
+	var externaldataResponse ProviderResponse
+	if err := json.Unmarshal(respBody, &externaldataResponse); err != nil {
+		return nil, http.StatusInternalServerError, fmt.Errorf("failed to unmarshal external data response: %w", err)
+	}
+
+	return &externaldataResponse, resp.StatusCode, nil
+}
+
 // ProviderKind strings are special string constants for Providers.
 // +kubebuilder:validation:Enum=ProviderRequestKind;ProviderResponseKind
 type ProviderKind string