rpcc buffer size may now be set from env var or form field

internal/app/xhttp/pkg/resource/arg.go

@@ -51,6 +51,9 @@ const (
 	// LandscapeArgKey is the key
 	// of the argument "landscape".
 	LandscapeArgKey ArgKey = "landscape"
+	// GoogleChromeRpccBufferSizeArgKey is the key
+	// of the argument "googleChromeRpccBufferSize".
+	GoogleChromeRpccBufferSizeArgKey ArgKey = "googleChromeRpccBufferSize"
 )
 
 /*
@@ -73,6 +76,7 @@ func ArgKeys() []ArgKey {
 		MarginLeftArgKey,
 		MarginRightArgKey,
 		LandscapeArgKey,
+		GoogleChromeRpccBufferSizeArgKey,
 	}
 }
 
@@ -265,3 +269,24 @@ func MarginArgs(r Resource, config conf.Config) (float64, float64, float64, floa
 		marginRight,
 		nil
 }
+
+/*
+GoogleChromeRpccBufferSizeArg is a helper for retrieving
+the "googleChromeRpccBufferSize" argument as int64.
+
+It also validates it against the application
+configuration.
+*/
+func GoogleChromeRpccBufferSizeArg(r Resource, config conf.Config) (int64, error) {
+	const op string = "resource.GoogleChromeRpccBufferSizeArg"
+	result, err := r.Int64Arg(
+		GoogleChromeRpccBufferSizeArgKey,
+		config.DefaultGoogleChromeRpccBufferSize(),
+		xassert.Int64NotInferiorTo(0.0),
+		xassert.Int64NotSuperiorTo(config.MaximumGoogleChromeRpccBufferSize()),
+	)
+	if err != nil {
+		return result, xerror.New(op, err)
+	}
+	return result, nil
+}

internal/app/xhttp/pkg/resource/arg_test.go

@@ -24,6 +24,7 @@ func TestArgKeys(t *testing.T) {
 		MarginLeftArgKey,
 		MarginRightArgKey,
 		LandscapeArgKey,
+		GoogleChromeRpccBufferSizeArgKey,
 	}
 	assert.Equal(t, expected, ArgKeys())
 }
@@ -300,3 +301,47 @@ func TestMarginArgs(t *testing.T) {
 	err = r.Close()
 	assert.Nil(t, err)
 }
+
+func TestGoogleChromeRpccBufferSizeArg(t *testing.T) {
+	const resourceDirectoryName string = "foo"
+	var expected int64
+	logger := test.DebugLogger()
+	config := conf.DefaultConfig()
+	r, err := New(logger, resourceDirectoryName)
+	assert.Nil(t, err)
+	// argument does not exist.
+	expected = config.DefaultGoogleChromeRpccBufferSize()
+	v, err := GoogleChromeRpccBufferSizeArg(r, config)
+	assert.Nil(t, err)
+	assert.Equal(t, expected, v)
+	// argument exist.
+	expected = 10
+	r.WithArg(GoogleChromeRpccBufferSizeArgKey, "10")
+	v, err = GoogleChromeRpccBufferSizeArg(r, config)
+	assert.Nil(t, err)
+	assert.Equal(t, expected, v)
+	// should not be OK as argument
+	// value is < 0.
+	expected = config.DefaultGoogleChromeRpccBufferSize()
+	r.WithArg(GoogleChromeRpccBufferSizeArgKey, "-1")
+	v, err = GoogleChromeRpccBufferSizeArg(r, config)
+	test.AssertError(t, err)
+	assert.Equal(t, expected, v)
+	// should not be OK as argument
+	// value is > config.MaximumGoogleChromeRpccBufferSize().
+	expected = config.DefaultGoogleChromeRpccBufferSize()
+	r.WithArg(GoogleChromeRpccBufferSizeArgKey, "104857601")
+	v, err = GoogleChromeRpccBufferSizeArg(r, config)
+	test.AssertError(t, err)
+	assert.Equal(t, expected, v)
+	// should not be OK as
+	// argument value is invalid.
+	expected = config.DefaultGoogleChromeRpccBufferSize()
+	r.WithArg(GoogleChromeRpccBufferSizeArgKey, "foo")
+	v, err = GoogleChromeRpccBufferSizeArg(r, config)
+	test.AssertError(t, err)
+	assert.Equal(t, expected, v)
+	// finally...
+	err = r.Close()
+	assert.Nil(t, err)
+}