[SLT-131] +X-API-Version http header, +versions.json (#3108)

* +X-API-Version http header, +versions.json

* lint

* switch to hard stop error upon version lookup failure

* error wrap

* lint

* versions.json path tweak

* abandoning versions.json in favor of versions.go

* lint

* convert json to struct

* lint

* lint

* tests for X-API-Version header

services/rfq/api/rest/handler.go

@@ -28,6 +28,14 @@ func NewHandler(db db.APIDB, cfg config.Config) *Handler {
 	}
 }
 
+// APIVersionMiddleware adds the X-API-Version header to the response with the current version # from versions.json file.
+func APIVersionMiddleware(serverVersion string) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		c.Writer.Header().Set("X-API-Version", serverVersion)
+		c.Next()
+	}
+}
+
 // ModifyQuote upserts a quote
 //
 // PUT /quotes

services/rfq/api/rest/server.go

@@ -3,6 +3,7 @@ package rest
 
 import (
 	"context"
+
 	"fmt"
 	"net/http"
 	"sync"
@@ -33,6 +34,14 @@ import (
 
 const meterName = "github.com/synapsecns/sanguine/services/rfq/api/rest"
 
+func getCurrentVersion() (string, error) {
+	if len(APIversions.Versions) == 0 {
+		return "", fmt.Errorf("no versions found")
+	}
+
+	return APIversions.Versions[0].Version, nil
+}
+
 // QuoterAPIServer is a struct that holds the configuration, database connection, gin engine, RPC client, metrics handler, and fast bridge contracts.
 // It is used to initialize and run the API server.
 type QuoterAPIServer struct {
@@ -158,6 +167,12 @@ func (r *QuoterAPIServer) Run(ctx context.Context) error {
 	// TODO: Use Gin Helper
 	engine := ginhelper.New(logger)
 	h := NewHandler(r.db, r.cfg)
+
+	versionNumber, versionNumErr := getCurrentVersion()
+	if versionNumErr != nil {
+		return fmt.Errorf("could not get current API version: %w", versionNumErr)
+	}
+	engine.Use(APIVersionMiddleware(versionNumber))
 	engine.GET("/swagger/*any", ginSwagger.WrapHandler(swaggerfiles.Handler))
 
 	// Apply AuthMiddleware only to the PUT routes

services/rfq/api/rest/server_test.go

@@ -59,6 +59,9 @@ func (c *ServerSuite) TestEIP191_SuccessfulSignature() {
 		c.Require().NoError(err)
 	}()
 
+	// Check for X-API-Version on the response
+	c.Equal(resp.Header.Get("X-API-Version"), rest.APIversions.Versions[0].Version)
+
 	// Assert that the response status code is HTTP 200 OK.
 	c.Equal(http.StatusOK, resp.StatusCode)
 }
@@ -146,6 +149,9 @@ func (c *ServerSuite) TestEIP191_SuccessfulPutSubmission() {
 		_ = resp.Body.Close()
 	}()
 
+	// Check for X-API-Version on the response
+	c.Equal(resp.Header.Get("X-API-Version"), rest.APIversions.Versions[0].Version)
+
 	// Log the response body for debugging.
 	body, err := io.ReadAll(resp.Body)
 	c.Require().NoError(err)
@@ -170,6 +176,9 @@ func (c *ServerSuite) TestPutAndGetQuote() {
 	}()
 	c.Assert().Equal(http.StatusOK, putResp.StatusCode)
 
+	// Check for X-API-Version on the response
+	c.Equal(putResp.Header.Get("X-API-Version"), rest.APIversions.Versions[0].Version)
+
 	// Send GET request to verify the PUT
 	client := &http.Client{}
 	req, err := http.NewRequestWithContext(c.GetTestContext(), http.MethodGet, fmt.Sprintf("http://localhost:%d/quotes?originChainId=1&originTokenAddr=0xOriginTokenAddrdestChainId=42161&destTokenAddr=0xDestTokenAddr", c.port), nil)
@@ -182,6 +191,9 @@ func (c *ServerSuite) TestPutAndGetQuote() {
 	}()
 	c.Assert().Equal(http.StatusOK, getResp.StatusCode)
 
+	// Check for X-API-Version on the response
+	c.Equal(getResp.Header.Get("X-API-Version"), rest.APIversions.Versions[0].Version)
+
 	var quotes []*model.GetQuoteResponse
 	err = json.NewDecoder(getResp.Body).Decode(&quotes)
 	c.Require().NoError(err)
@@ -212,6 +224,9 @@ func (c *ServerSuite) TestPutAndGetQuoteByRelayer() {
 	}()
 	c.Assert().Equal(http.StatusOK, putResp.StatusCode)
 
+	// Check for X-API-Version on the response
+	c.Equal(putResp.Header.Get("X-API-Version"), rest.APIversions.Versions[0].Version)
+
 	// Send GET request to verify the PUT
 	client := &http.Client{}
 	req, err := http.NewRequestWithContext(c.GetTestContext(), http.MethodGet, fmt.Sprintf("http://localhost:%d/quotes?relayerAddress=%s", c.port, c.testWallet.Address().Hex()), nil)
@@ -224,6 +239,9 @@ func (c *ServerSuite) TestPutAndGetQuoteByRelayer() {
 	}()
 	c.Assert().Equal(http.StatusOK, getResp.StatusCode)
 
+	// Check for X-API-Version on the response
+	c.Equal(getResp.Header.Get("X-API-Version"), rest.APIversions.Versions[0].Version)
+
 	var quotes []*model.GetQuoteResponse
 	err = json.NewDecoder(getResp.Body).Decode(&quotes)
 	c.Require().NoError(err)
@@ -264,6 +282,9 @@ func (c *ServerSuite) TestMultiplePutRequestsWithIncorrectAuth() {
 		body, err := io.ReadAll(resp.Body)
 		c.Require().NoError(err)
 
+		// Check for X-API-Version on the response
+		c.Equal(resp.Header.Get("X-API-Version"), rest.APIversions.Versions[0].Version)
+
 		// Log the response body for debugging
 		fmt.Printf("Request %d response: Status: %d, Body: %s\n", i+1, resp.StatusCode, string(body))
 
@@ -323,6 +344,9 @@ func (c *ServerSuite) TestPutAck() {
 	err = resp.Body.Close()
 	c.Require().NoError(err)
 
+	// Check for X-API-Version on the response
+	c.Equal(resp.Header.Get("X-API-Version"), rest.APIversions.Versions[0].Version)
+
 	// Send another request with same txID
 	header, err = c.prepareAuthHeader(c.testWallet)
 	c.Require().NoError(err)

services/rfq/api/rest/versions.go

@@ -0,0 +1,27 @@
+package rest
+
+// APIVersionHistory lists historical ApiVersion structs in descending chronological order (current version index 0), each containing further detail about the version.
+type APIVersionHistory struct {
+	Versions []APIVersion `json:"versions"`
+}
+
+// APIVersion specifies the date of a particular API version along with any comments & alerts for integrators to review.
+type APIVersion struct {
+	Version  string `json:"version"`
+	Date     string `json:"date"`
+	Comments string `json:"comments"`
+	Alerts   string `json:"alerts"`
+}
+
+// APIversions contains version information for the Synapse RFQ API. Deprecation notices & other alerts, if any, will be listed here.
+// Note: Items must be listed in descending chronological order (current version index 0).
+var APIversions = APIVersionHistory{
+	Versions: []APIVersion{
+		{
+			Version:  "1.0",
+			Date:     "2024-01-01",
+			Comments: "",
+			Alerts:   "",
+		},
+	},
+}