Added dac module with fulfillment tracking

dac/go.mod

@@ -0,0 +1,3 @@
+module github.com/cerebellum-network/cere-ddc-sdk-go/dac
+
+go 1.18

dac/pkg/collection_point.go

@@ -0,0 +1,90 @@
+package dac
+
+import (
+	"bytes"
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"github.com/cerebellum-network/cere-ddc-sdk-go/core/pkg/crypto"
+	"io"
+	"net/http"
+	"net/url"
+	"strconv"
+	"time"
+)
+
+type (
+	CollectionPoint interface {
+		SaveFulfillment(fulfillment Fulfillment) error
+	}
+
+	dacCollectionPoint struct {
+		url        url.URL
+		httpClient http.Client
+	}
+
+	Fulfillment struct {
+		SessionId          []byte `json:"sessionId"`
+		RequestId          string `json:"requestId"`
+		Cid                string `json:"cid"`
+		OpCode             uint8  `json:"opCode"`
+		BytesSent          uint32 `json:"bytesSent"`
+		FulfilledTimestamp uint64 `json:"fulfilledTimestamp"`
+		WorkerSignature    []byte `json:"workerSignature"`
+		WorkerAddress      string `json:"workerAddress"`
+	}
+)
+
+const (
+	dacTimeout      = 10 * time.Second
+	fulfillmentPath = "/fulfillment"
+)
+
+func CreateCollectionPoint(url url.URL, httpClient http.Client) CollectionPoint {
+	return &dacCollectionPoint{
+		url,
+		httpClient,
+	}
+}
+
+func (d dacCollectionPoint) SaveFulfillment(fulfillment Fulfillment) error {
+	json, err := json.Marshal(fulfillment)
+	if err != nil {
+		return err
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), dacTimeout)
+	defer cancel()
+
+	req, err := http.NewRequestWithContext(
+		ctx,
+		"POST",
+		d.url.String()+fulfillmentPath,
+		bytes.NewBuffer(json),
+	)
+
+	req.Header.Set("Content-Type", "application/json")
+
+	if err != nil {
+		return fmt.Errorf("failed to create request: %w", err)
+	}
+
+	if response, err := d.httpClient.Do(req); err != nil {
+		return err
+	} else if response.StatusCode != http.StatusOK {
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("DAC collection point post: %d %s", response.StatusCode, string(body))
+	}
+
+	return nil
+}
+
+func SignFulfillment(fulfillment *Fulfillment, scheme crypto.Scheme) error {
+	signature, err := scheme.Sign([]byte(fulfillment.Cid + base64.StdEncoding.EncodeToString(fulfillment.SessionId) + fulfillment.RequestId + strconv.FormatUint(fulfillment.FulfilledTimestamp, 10)))
+	if err != nil {
+		return err
+	}
+	fulfillment.WorkerSignature = signature
+	return nil
+}

go.work

@@ -6,4 +6,5 @@ use (
 	./core
 	./model
 	./test
+	dac
 )