Ship call logs to the user as text/plain instead of JSON (#615)

* Ship call logs to the user as text/plain instead of JSON

* Fixing swagger doc

* c.String instead of c.JSON

* Make Logs API backward compatible

* Loop over accepted MIME types

* Bump swagger API version

* Fix client build script

 previous version was producing the following "couldn't find a swagger spec"

* Logs API regression test

* Write response body without buffering

* Switch JSON and text/plain cases

* Handle Accepted content types properly

* More solid response content type handling

* Write HTTP 406 with corresponding error body

* Remove unused import

* Use handleErrorResponse

api/server/call_logs.go

@@ -2,13 +2,33 @@ package server
 
 import (
 	"bytes"
+	"io"
 	"net/http"
 
+	"errors"
 	"github.com/fnproject/fn/api"
 	"github.com/fnproject/fn/api/models"
 	"github.com/gin-gonic/gin"
+	"strings"
 )
 
+// note: for backward compatibility, will go away later
+type callLogResponse struct {
+	Message string          `json:"message"`
+	Log     *models.CallLog `json:"log"`
+}
+
+func writeJSON(c *gin.Context, callID, appName string, logReader io.Reader) {
+	var b bytes.Buffer
+	b.ReadFrom(logReader)
+	c.JSON(http.StatusOK, callLogResponse{"Successfully loaded log",
+		&models.CallLog{
+			CallID:  callID,
+			AppName: appName,
+			Log:     b.String(),
+		}})
+}
+
 func (s *Server) handleCallLogGet(c *gin.Context) {
 	ctx := c.Request.Context()
 
@@ -21,18 +41,30 @@ func (s *Server) handleCallLogGet(c *gin.Context) {
 		return
 	}
 
-	// TODO this API needs to change to text/plain / gzip anyway, punting
-	// optimization, but we can write this direct to the wire, too... seems like
-	// we should write some kind of writev json thing for go since we keep
-	// hitting this :(
-	var b bytes.Buffer
-	b.ReadFrom(logReader)
+	mimeTypes, _ := c.Request.Header["Accept"]
 
-	callObj := models.CallLog{
-		CallID:  callID,
-		AppName: appName,
-		Log:     b.String(),
+	if len(mimeTypes) == 0 {
+		writeJSON(c, callID, appName, logReader)
+		return
 	}
 
-	c.JSON(http.StatusOK, callLogResponse{"Successfully loaded log", &callObj})
+	for _, mimeType := range mimeTypes {
+		if strings.Contains(mimeType, "application/json") {
+			writeJSON(c, callID, appName, logReader)
+			return
+		}
+		if strings.Contains(mimeType, "text/plain") {
+			io.Copy(c.Writer, logReader)
+			return
+
+		}
+		if strings.Contains(mimeType, "*/*") {
+			writeJSON(c, callID, appName, logReader)
+			return
+		}
+	}
+
+	// if we've reached this point it means that Fn didn't recognize Accepted content type
+	handleErrorResponse(c, models.NewAPIError(http.StatusNotAcceptable,
+		errors.New("unable to respond within acceptable response content types")))
 }

api/server/server.go

@@ -524,8 +524,3 @@ type callsResponse struct {
 	NextCursor string         `json:"next_cursor"`
 	Calls      []*models.Call `json:"calls"`
 }
-
-type callLogResponse struct {
-	Message string          `json:"message"`
-	Log     *models.CallLog `json:"log"`
-}

clients/build.rb

@@ -87,7 +87,7 @@ languages.each do |l|
   destdir = "tmp/fn_#{lshort}"
   if l == 'go'
     # This is using https://goswagger.io/ instead
-    stream_exec "docker run --rm -v ${PWD}/#{clone_dir}:/go/src/github.com/fnproject/fn_go -w /go/src/github.com/fnproject/fn_go quay.io/goswagger/swagger generate client -f #{swaggerUrl} -A fn "
+    stream_exec "docker run --rm -v ${PWD}/#{clone_dir}:/go/src/github.com/fnproject/fn_go -v ${GOPATH}/src/github.com/fnproject/fn/docs/swagger.yml:/go/src/github.com/fnproject/fn/swagger.yml -w /go/src/github.com/fnproject/fn_go quay.io/goswagger/swagger generate client -f /go/src/github.com/fnproject/fn/swagger.yml -A fn "
   else
     gen = JSON.parse(HTTP.post("https://generator.swagger.io/api/gen/clients/#{l}",
       json: {

docs/swagger.yml

@@ -2,7 +2,7 @@ swagger: '2.0'
 info:
   title: fn
   description: The open source serverless platform.
-  version: "0.2.2"
+  version: "0.2.3"
 # the domain of the service
 host: "127.0.0.1:8080"
 # array of all schemes that your API supports
@@ -371,6 +371,7 @@ paths:
       tags:
         - Call
         - Log
+      produces: ['text/plain',]
       parameters:
         - name: app
           description: App Name
@@ -386,7 +387,7 @@ paths:
         200:
           description: Log found
           schema:
-            $ref:  '#/definitions/LogWrapper'
+            type: string
         404:
           description: Log not found.
           schema:
@@ -636,25 +637,6 @@ definitions:
         $ref: '#/definitions/Call'
         description: "Call object."
 
-
-  LogWrapper:
-    type: object
-    required:
-      - log
-    properties:
-      log:
-        $ref: '#/definitions/Log'
-        description: "Call log entry."
-
-  Log:
-    type: object
-    properties:
-      call_id:
-        type: string
-        description: Call UUID ID
-      log:
-        type: string # maybe bytes, long logs wouldn't fit into string type
-
   Call:
     type: object
     properties: