From 56dfed531bfa19c954871ace58437e575335110d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mislav=20Marohni=C4=87?= <mislav@github.com>
Date: Wed, 10 Aug 2022 10:53:07 +0200
Subject: [PATCH] api: fix writing response headers to terminal pager

---
 pkg/cmd/api/api.go      | 29 ++++++++++++++++-------------
 pkg/cmd/api/api_test.go |  2 +-
 pkg/export/template.go  |  6 ++----
 3 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/pkg/cmd/api/api.go b/pkg/cmd/api/api.go
index 02b288fa6..73bb66157 100644
--- a/pkg/cmd/api/api.go
+++ b/pkg/cmd/api/api.go
@@ -272,10 +272,7 @@ func apiRun(opts *ApiOptions) error {
 		httpClient = api.NewCachedHTTPClient(httpClient, opts.CacheTTL)
 	}
 
-	headersOutputStream := opts.IO.Out
-	if opts.Silent {
-		opts.IO.Out = io.Discard
-	} else {
+	if !opts.Silent {
 		if err := opts.IO.StartPager(); err == nil {
 			defer opts.IO.StopPager()
 		} else {
@@ -283,6 +280,12 @@ func apiRun(opts *ApiOptions) error {
 		}
 	}
 
+	bodyWriter := opts.IO.Out
+	headersWriter := opts.IO.Out
+	if opts.Silent {
+		bodyWriter = io.Discard
+	}
+
 	cfg, err := opts.Config()
 	if err != nil {
 		return err
@@ -303,7 +306,7 @@ func apiRun(opts *ApiOptions) error {
 			return err
 		}
 
-		endCursor, err := processResponse(resp, opts, headersOutputStream, &template)
+		endCursor, err := processResponse(resp, opts, bodyWriter, headersWriter, &template)
 		if err != nil {
 			return err
 		}
@@ -330,11 +333,11 @@ func apiRun(opts *ApiOptions) error {
 	return template.End()
 }
 
-func processResponse(resp *http.Response, opts *ApiOptions, headersOutputStream io.Writer, template *export.Template) (endCursor string, err error) {
+func processResponse(resp *http.Response, opts *ApiOptions, bodyWriter, headersWriter io.Writer, template *export.Template) (endCursor string, err error) {
 	if opts.ShowResponseHeaders {
-		fmt.Fprintln(headersOutputStream, resp.Proto, resp.Status)
-		printHeaders(headersOutputStream, resp.Header, opts.IO.ColorEnabled())
-		fmt.Fprint(headersOutputStream, "\r\n")
+		fmt.Fprintln(headersWriter, resp.Proto, resp.Status)
+		printHeaders(headersWriter, resp.Header, opts.IO.ColorEnabled())
+		fmt.Fprint(headersWriter, "\r\n")
 	}
 
 	if resp.StatusCode == 204 {
@@ -362,20 +365,20 @@ func processResponse(resp *http.Response, opts *ApiOptions, headersOutputStream
 
 	if opts.FilterOutput != "" && serverError == "" {
 		// TODO: reuse parsed query across pagination invocations
-		err = export.FilterJSON(opts.IO.Out, responseBody, opts.FilterOutput)
+		err = export.FilterJSON(bodyWriter, responseBody, opts.FilterOutput)
 		if err != nil {
 			return
 		}
 	} else if opts.Template != "" && serverError == "" {
 		// TODO: reuse parsed template across pagination invocations
-		err = template.Execute(responseBody)
+		err = template.Execute(bodyWriter, responseBody)
 		if err != nil {
 			return
 		}
 	} else if isJSON && opts.IO.ColorEnabled() {
-		err = jsoncolor.Write(opts.IO.Out, responseBody, "  ")
+		err = jsoncolor.Write(bodyWriter, responseBody, "  ")
 	} else {
-		_, err = io.Copy(opts.IO.Out, responseBody)
+		_, err = io.Copy(bodyWriter, responseBody)
 	}
 	if err != nil {
 		return
diff --git a/pkg/cmd/api/api_test.go b/pkg/cmd/api/api_test.go
index bb6928d66..0e25cd7f4 100644
--- a/pkg/cmd/api/api_test.go
+++ b/pkg/cmd/api/api_test.go
@@ -1299,7 +1299,7 @@ func Test_processResponse_template(t *testing.T) {
 		Template: `{{range .}}{{.title}} ({{.labels | pluck "name" | join ", " }}){{"\n"}}{{end}}`,
 	}
 	template := export.NewTemplate(ios, opts.Template)
-	_, err := processResponse(&resp, &opts, io.Discard, &template)
+	_, err := processResponse(&resp, &opts, ios.Out, io.Discard, &template)
 	require.NoError(t, err)
 
 	err = template.End()
diff --git a/pkg/export/template.go b/pkg/export/template.go
index bc0986d78..83630e1ae 100644
--- a/pkg/export/template.go
+++ b/pkg/export/template.go
@@ -76,9 +76,7 @@ func (t *Template) parseTemplate(tpl string) (*template.Template, error) {
 	return template.New("").Funcs(templateFuncs).Parse(tpl)
 }
 
-func (t *Template) Execute(input io.Reader) error {
-	w := t.io.Out
-
+func (t *Template) Execute(w io.Writer, input io.Reader) error {
 	if t.template == nil {
 		template, err := t.parseTemplate(t.templateStr)
 		if err != nil {
@@ -103,7 +101,7 @@ func (t *Template) Execute(input io.Reader) error {
 
 func ExecuteTemplate(io *iostreams.IOStreams, input io.Reader, template string) error {
 	t := NewTemplate(io, template)
-	if err := t.Execute(input); err != nil {
+	if err := t.Execute(io.Out, input); err != nil {
 		return err
 	}
 	return t.End()