feat: support use of Context with RequestBuilder

Fixes arf/planning-sdk-squad#2230
Fixes #77

This commit adds support for setting a context.Context
instance on the RequestBuilder struct.  This Context instance
will then be associated with the http.Request instance constructed
by the RequestBuilder.Build() method.

BREAKING CHANGE: Minimum supported Go version is now 1.13.
The minimum version of Go supported by this library has been changed
to Go version 1.13. To use this and future versions of the
Go core library, please make sure that you are using
Go version 1.13 or higher.

.bumpversion.cfg

@@ -3,16 +3,10 @@ current_version = 4.6.1
 commit = True
 message = Update version numbers from {current_version} -> {new_version} [skip ci]
 
-[bumpversion:file:v4/core/version.go]
+[bumpversion:file:v5/core/version.go]
 search = __VERSION__ = "{current_version}"
 replace = __VERSION__ = "{new_version}"
 
-[bumpversion:file:v4/go.mod]
-parse = (?P<major>\d+)
-serialize = {major}
-search = module github.com/IBM/go-sdk-core/v{current_version}
-replace = module github.com/IBM/go-sdk-core/v{new_version}
-
 [bumpversion:file:Makefile]
 parse = (?P<major>\d+)
 serialize = {major}

.travis.yml

@@ -3,23 +3,19 @@ language: go
 dist: xenial
 
 go:
-- 1.12.x
+- 1.13.x
 
 notifications:
   email: false
 
-env:
-  global:
-    - GO111MODULE=on
-
 before_install:
   - nvm install 12
   - npm install -g npm@6.x
   - sudo apt-get update
   - sudo apt-get install python
 
 install:
-  - curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh| sh -s -- -b $(go env GOPATH)/bin v1.21.0
+  - curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh| sh -s -- -b $(go env GOPATH)/bin v1.31.0
 
 script:
   - make all

CONTRIBUTING.md

@@ -30,9 +30,9 @@ If you want to contribute to the repository, here's a quick guide:
 
   4. Install the `golangci-lint` tool:
      ```sh
-     curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh| sh -s -- -b $(go env GOPATH)/bin v1.21.0
+        curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh| sh -s -- -b $(go env GOPATH)/bin v1.31.0
      ```  
-  * Note: As of this writing, the 1.21.0 version of `golangci-lint` is being used by this project.
+  * Note: As of this writing, the 1.31.0 version of `golangci-lint` is being used by this project.
   Please check the `curl` command found in the `.travis.yml` file to see the version of this tool that is currently 
   being used at the time you are planning to commit changes. This will ensure that you are using the same version 
   of the linter as the Travis build automation, which will ensure that you are using the same set of linter checks
@@ -42,12 +42,12 @@ If you want to contribute to the repository, here's a quick guide:
 
   6. Test your changes:
      ```sh
-     go test ./...
+     make test
      ```  
 
   7. Check your code for lint issues
      ```sh
-     golangci-lint run
+     make lint
      ```  
 
   8. Commit your changes:

Makefile

@@ -1,6 +1,6 @@
 # Makefile to build go-sdk-core library
 
-VDIR=v4
+VDIR=v5
 
 all: build test lint tidy
 

README.md

@@ -13,7 +13,7 @@ go get -u github.com/IBM/go-sdk-core/...
 ```
 
 ## Prerequisites
-- Go version 1.12 or newer
+- Go version 1.13 or newer
 
 ## Authentication
 The go-sdk-core project supports the following types of authentication:
@@ -32,15 +32,9 @@ Before opening a new issue, please search for similar issues. It's possible that
 
 ## Tests
 
-Run all test suites:
+To build, test and lint-check the project:
 ```bash
-go test ./...
-```
-
-Get code coverage for each test suite:
-```bash
-go test -coverprofile=coverage.out ./...
-go tool cover -html=coverage.out
+make all
 ```
 
 ## Contributing

v4/core/request_builder.go → v5/core/request_builder.go

@@ -16,6 +16,7 @@ package core
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -76,6 +77,13 @@ type RequestBuilder struct {
 	// the "Content-Encoding" header will be added to the request with the
 	// value "gzip".
 	EnableGzipCompression bool
+
+	// RequestContext can be used by users of RequestBuilder to provide an
+	// optional context.Context instance to be associated with the http.Request
+	// instance that will be built by the Build() method.
+	// If specified, then http.NewRequestWithContext() is used to create the
+	// http.Request instance.  If nil, then http.NewRequest() is used instead.
+	RequestContext *context.Context
 }
 
 // NewRequestBuilder initiates a new request.
@@ -275,7 +283,7 @@ func (requestBuilder *RequestBuilder) SetBodyContentForMultipart(contentType str
 }
 
 // Build builds an HTTP Request object from this RequestBuilder instance.
-func (requestBuilder *RequestBuilder) Build() (*http.Request, error) {
+func (requestBuilder *RequestBuilder) Build() (req *http.Request, err error) {
 	// Create multipart form data
 	if len(requestBuilder.Form) > 0 {
 		// handle both application/x-www-form-urlencoded or multipart/form-data
@@ -287,29 +295,31 @@ func (requestBuilder *RequestBuilder) Build() (*http.Request, error) {
 					data.Add(fieldName, v.contents.(string))
 				}
 			}
-			_, err := requestBuilder.SetBodyContentString(data.Encode())
+			_, err = requestBuilder.SetBodyContentString(data.Encode())
 			if err != nil {
-				return nil, err
+				return
 			}
 		} else {
 			formWriter := requestBuilder.createMultipartWriter()
 			for fieldName, l := range requestBuilder.Form {
 				for _, v := range l {
-					dataPartWriter, err := createFormFile(formWriter, fieldName, v.fileName, v.contentType)
+					var dataPartWriter io.Writer
+					dataPartWriter, err = createFormFile(formWriter, fieldName, v.fileName, v.contentType)
 					if err != nil {
-						return nil, err
+						return
 					}
-					if err = requestBuilder.SetBodyContentForMultipart(v.contentType,
-						v.contents, dataPartWriter); err != nil {
-						return nil, err
+
+					err = requestBuilder.SetBodyContentForMultipart(v.contentType, v.contents, dataPartWriter)
+					if err != nil {
+						return
 					}
 				}
 			}
 
 			requestBuilder.AddHeader("Content-Type", formWriter.FormDataContentType())
-			err := formWriter.Close()
+			err = formWriter.Close()
 			if err != nil {
-				return nil, err
+				return
 			}
 		}
 	}
@@ -318,18 +328,23 @@ func (requestBuilder *RequestBuilder) Build() (*http.Request, error) {
 	// and add the "Content-Encoding: gzip" request header.
 	if !IsNil(requestBuilder.Body) && requestBuilder.EnableGzipCompression &&
 		!SliceContains(requestBuilder.Header[CONTENT_ENCODING], "gzip") {
-		newBody, err := NewGzipCompressionReader(requestBuilder.Body)
+		var newBody io.Reader
+		newBody, err = NewGzipCompressionReader(requestBuilder.Body)
 		if err != nil {
-			return nil, err
+			return
 		}
 		requestBuilder.Body = newBody
 		requestBuilder.Header.Add(CONTENT_ENCODING, "gzip")
 	}
 
 	// Create the request
-	req, err := http.NewRequest(requestBuilder.Method, requestBuilder.URL.String(), requestBuilder.Body)
+	if requestBuilder.RequestContext != nil {
+		req, err = http.NewRequestWithContext(*requestBuilder.RequestContext, requestBuilder.Method, requestBuilder.URL.String(), requestBuilder.Body)
+	} else {
+		req, err = http.NewRequest(requestBuilder.Method, requestBuilder.URL.String(), requestBuilder.Body)
+	}
 	if err != nil {
-		return nil, err
+		return
 	}
 
 	// Headers
@@ -345,7 +360,7 @@ func (requestBuilder *RequestBuilder) Build() (*http.Request, error) {
 	// Encode query
 	req.URL.RawQuery = query.Encode()
 
-	return req, nil
+	return
 }
 
 // SetBodyContent sets the body content from one of three different sources.

v4/core/request_builder_test.go → v5/core/request_builder_test.go

@@ -16,9 +16,14 @@ package core
 
 import (
 	"bytes"
+	"context"
+	"fmt"
 	"io"
+	"net/http"
+	"net/http/httptest"
 	"os"
 	"testing"
+	"time"
 
 	assert "github.com/stretchr/testify/assert"
 )
@@ -593,3 +598,78 @@ func TestBuild(t *testing.T) {
 	assert.Equal(t, wantURL, request.URL.String())
 	assert.Equal(t, "Application/json", request.Header["Content-Type"][0])
 }
+
+func TestRequestWithContext(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-type", "application/json")
+		w.WriteHeader(http.StatusOK)
+		fmt.Fprint(w, `{"name": "wonder woman"}`)
+	}))
+	defer server.Close()
+
+	ctx, cancelFunc := context.WithTimeout(context.Background(), 3*time.Second)
+	defer cancelFunc()
+
+	builder := NewRequestBuilder("GET")
+	builder.RequestContext = &ctx
+	_, err := builder.ConstructHTTPURL(server.URL, nil, nil)
+	assert.Nil(t, err)
+	req, _ := builder.Build()
+
+	authenticator, _ := NewNoAuthAuthenticator()
+
+	options := &ServiceOptions{
+		URL:           server.URL,
+		Authenticator: authenticator,
+	}
+	service, err := NewBaseService(options)
+	assert.Nil(t, err)
+
+	var foo *Foo
+	detailedResponse, err := service.Request(req, &foo)
+	assert.Nil(t, err)
+	assert.NotNil(t, detailedResponse)
+	assert.Equal(t, http.StatusOK, detailedResponse.StatusCode)
+	assert.Equal(t, "application/json", detailedResponse.Headers.Get("Content-Type"))
+
+	result, ok := detailedResponse.Result.(*Foo)
+	assert.Equal(t, true, ok)
+	assert.NotNil(t, result)
+	assert.NotNil(t, foo)
+	assert.Equal(t, "wonder woman", *(result.Name))
+}
+
+func TestRequestWithContextTimeout(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-type", "application/json")
+		w.WriteHeader(http.StatusOK)
+		time.Sleep(3 * time.Second)
+		fmt.Fprint(w, `{"name": "wonder woman"}`)
+	}))
+	defer server.Close()
+
+	ctx, cancelFunc := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancelFunc()
+
+	builder := NewRequestBuilder("GET")
+	builder.RequestContext = &ctx
+	_, err := builder.ConstructHTTPURL(server.URL, nil, nil)
+	assert.Nil(t, err)
+	req, _ := builder.Build()
+
+	authenticator, _ := NewNoAuthAuthenticator()
+
+	options := &ServiceOptions{
+		URL:           server.URL,
+		Authenticator: authenticator,
+	}
+	service, err := NewBaseService(options)
+	assert.Nil(t, err)
+
+	var foo *Foo
+	detailedResponse, err := service.Request(req, &foo)
+	assert.NotNil(t, err)
+	t.Logf("Expected error: %s\n", err.Error())
+	assert.Contains(t, err.Error(), "context deadline exceeded")
+	assert.Nil(t, detailedResponse)
+}

v4/go.mod → v5/go.mod

@@ -1,6 +1,6 @@
-module github.com/IBM/go-sdk-core/v4
+module github.com/IBM/go-sdk-core/v5
 
-go 1.12
+go 1.13
 
 require (
 	github.com/dgrijalva/jwt-go v3.2.0+incompatible