Add cctp v2 client (#1344)

* Add CCTPv2 HTTP client

* Add unit tests

* Add tests for parseResponseBody

* fix lint errors

* Add links to CCTPv2 API docs

* Add httpStatus to metrics

Author: rstout

execute/tokendata/cctp/v2/http_client.go

@@ -0,0 +1,192 @@
+// Package v2 provides an HTTP client wrapper for Circle's CCTP v2 attestation API.
+// This package handles the HTTP communication layer for fetching CCTP v2 messages
+// and attestations from Circle's API endpoints.
+// The CCTPv2 "get messages" API is documented here:
+// https://developers.circle.com/api-reference/cctp/all/get-messages-v-2
+package v2
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/smartcontractkit/chainlink-common/pkg/logger"
+	cciptypes "github.com/smartcontractkit/chainlink-common/pkg/types/ccipocr3"
+
+	httputil "github.com/smartcontractkit/chainlink-ccip/execute/tokendata/http"
+	"github.com/smartcontractkit/chainlink-ccip/pluginconfig"
+)
+
+const (
+	apiVersionV2 = "v2"
+	messagesPath = "messages"
+)
+
+type CCTPv2HTTPClient interface {
+	GetMessages(
+		ctx context.Context, sourceChain cciptypes.ChainSelector, sourceDomainID uint32, transactionHash string,
+	) (CCTPv2Messages, error)
+}
+
+// MetricsReporter provides metrics reporting for attestation API calls
+type MetricsReporter interface {
+	TrackAttestationAPILatency(
+		sourceChain cciptypes.ChainSelector, sourceDomain uint32, success bool, httpStatus string, latency time.Duration)
+}
+
+// CCTPv2HTTPClientImpl implements CCTPv2AttestationClient using HTTP calls to Circle's attestation API
+type CCTPv2HTTPClientImpl struct {
+	lggr            logger.Logger
+	client          httputil.HTTPClient
+	metricsReporter MetricsReporter
+}
+
+// NewCCTPv2Client creates a new HTTP-based CCTP v2 attestation client
+func NewCCTPv2Client(
+	lggr logger.Logger,
+	config pluginconfig.USDCCCTPObserverConfig,
+	metricsReporter MetricsReporter,
+) (*CCTPv2HTTPClientImpl, error) {
+	if lggr == nil {
+		return nil, fmt.Errorf("logger cannot be nil")
+	}
+	if metricsReporter == nil {
+		return nil, fmt.Errorf("metricsReporter cannot be nil")
+	}
+
+	client, err := httputil.GetHTTPClient(
+		lggr,
+		config.AttestationAPI,
+		config.AttestationAPIInterval.Duration(),
+		config.AttestationAPITimeout.Duration(),
+		config.AttestationAPICooldown.Duration(),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("create HTTP client: %w", err)
+	}
+	return &CCTPv2HTTPClientImpl{
+		lggr:            lggr,
+		client:          client,
+		metricsReporter: metricsReporter,
+	}, nil
+}
+
+// GetMessages fetches CCTP v2 messages and attestations for the given transaction.
+func (c *CCTPv2HTTPClientImpl) GetMessages(
+	ctx context.Context,
+	sourceChain cciptypes.ChainSelector,
+	sourceDomainID uint32,
+	transactionHash string,
+) (CCTPv2Messages, error) {
+	startTime := time.Now()
+	success := false
+	httpStatus := ""
+
+	defer func() {
+		latency := time.Since(startTime)
+		c.metricsReporter.TrackAttestationAPILatency(sourceChain, sourceDomainID, success, httpStatus, latency)
+	}()
+
+	// Validate transaction hash
+	if transactionHash == "" {
+		return CCTPv2Messages{}, fmt.Errorf("transaction hash cannot be empty")
+	}
+	if !strings.HasPrefix(transactionHash, "0x") || len(transactionHash) != 66 {
+		return CCTPv2Messages{}, fmt.Errorf("invalid transaction hash format: %s", transactionHash)
+	}
+
+	path := fmt.Sprintf("%s/%s/%d?transactionHash=%s",
+		apiVersionV2, messagesPath, sourceDomainID, url.QueryEscape(transactionHash))
+	body, status, err := c.client.Get(ctx, path)
+	httpStatus = strconv.Itoa(int(status))
+
+	if err != nil {
+		return CCTPv2Messages{},
+			fmt.Errorf("http call failed to get CCTPv2 messages for sourceDomainID %d and transactionHash %s, error: %w",
+				sourceDomainID, transactionHash, err)
+	}
+
+	if status != http.StatusOK {
+		c.lggr.Warnw(
+			"Non-200 status from Circle API",
+			"status", status,
+			"path", path,
+			"sourceDomainID", sourceDomainID,
+			"transactionHash", transactionHash,
+			"responseBody", string(body),
+		)
+		return CCTPv2Messages{}, fmt.Errorf(
+			"circle API returned status %d for path %s", status, path)
+	}
+
+	result, err := parseResponseBody(body)
+	if err != nil {
+		return CCTPv2Messages{}, err
+	}
+
+	success = true
+	return result, nil
+}
+
+// parseResponseBody parses the JSON response from Circle's attestation API
+// and returns a CCTPv2Messages struct containing the decoded CCTP v2 messages.
+func parseResponseBody(body cciptypes.Bytes) (CCTPv2Messages, error) {
+	var messages CCTPv2Messages
+	if err := json.Unmarshal(body, &messages); err != nil {
+		return CCTPv2Messages{}, fmt.Errorf("failed to decode json: %w", err)
+	}
+	return messages, nil
+}
+
+// CCTPv2Messages represents the response structure from Circle's attestation API,
+// containing a list of CCTP v2 messages with their attestations.
+// This API response type is documented here:
+// https://developers.circle.com/api-reference/cctp/all/get-messages-v-2
+type CCTPv2Messages struct {
+	Messages []CCTPv2Message `json:"messages"`
+}
+
+// CCTPv2Message represents a single CCTP v2 message from Circle's attestation API.
+// It contains the message data, attestation signature, and decoded message details
+// needed for cross-chain USDC transfers.
+type CCTPv2Message struct {
+	Message        string               `json:"message"`
+	EventNonce     string               `json:"eventNonce"`
+	Attestation    string               `json:"attestation"`
+	DecodedMessage CCTPv2DecodedMessage `json:"decodedMessage"`
+	CCTPVersion    int                  `json:"cctpVersion"`
+	Status         string               `json:"status"`
+}
+
+// CCTPv2DecodedMessage represents the 'decodedMessage' object within a CCTPv2Message.
+type CCTPv2DecodedMessage struct {
+	SourceDomain       string                   `json:"sourceDomain"`
+	DestinationDomain  string                   `json:"destinationDomain"`
+	Nonce              string                   `json:"nonce"`
+	Sender             string                   `json:"sender"`
+	Recipient          string                   `json:"recipient"`
+	DestinationCaller  string                   `json:"destinationCaller"`
+	MessageBody        string                   `json:"messageBody"`
+	DecodedMessageBody CCTPv2DecodedMessageBody `json:"decodedMessageBody"`
+	// The following fields are optional.
+	MinFinalityThreshold      string `json:"minFinalityThreshold,omitempty"`
+	FinalityThresholdExecuted string `json:"finalityThresholdExecuted,omitempty"`
+}
+
+// CCTPv2DecodedMessageBody represents the 'decodedMessageBody' object within a CCTPv2DecodedMessage.
+type CCTPv2DecodedMessageBody struct {
+	BurnToken     string `json:"burnToken"`
+	MintRecipient string `json:"mintRecipient"`
+	Amount        string `json:"amount"`
+	MessageSender string `json:"messageSender"`
+	// The following fields are optional.
+	MaxFee          string `json:"maxFee,omitempty"`
+	FeeExecuted     string `json:"feeExecuted,omitempty"`
+	ExpirationBlock string `json:"expirationBlock,omitempty"`
+	HookData        string `json:"hookData,omitempty"`
+}