Add build.UseResourceCacheWhen

Fixes #6993

2 files changed, 106 insertions, 0 deletions

diff --git a/config/sitemap.go b/config/commonConfig.go
index 4031b7ec1..ab2cfe80b 100644
--- a/config/sitemap.go
+++ b/config/commonConfig.go
@@ -14,10 +14,56 @@
 package config
 
 import (
+	"strings"
+
+	"github.com/gohugoio/hugo/common/herrors"
+	"github.com/mitchellh/mapstructure"
 	"github.com/spf13/cast"
 	jww "github.com/spf13/jwalterweatherman"
 )
 
+var DefaultBuild = Build{
+	UseResourceCacheWhen: "fallback",
+}
+
+// Build holds some build related condfiguration.
+type Build struct {
+	UseResourceCacheWhen string // never, fallback, always. Default is fallback
+}
+
+func (b Build) UseResourceCache(err error) bool {
+	if b.UseResourceCacheWhen == "never" {
+		return false
+	}
+
+	if b.UseResourceCacheWhen == "fallback" {
+		return err == herrors.ErrFeatureNotAvailable
+	}
+
+	return true
+}
+
+func DecodeBuild(cfg Provider) Build {
+	m := cfg.GetStringMap("build")
+	b := DefaultBuild
+	if m == nil {
+		return b
+	}
+
+	err := mapstructure.WeakDecode(m, &b)
+	if err != nil {
+		return DefaultBuild
+	}
+
+	b.UseResourceCacheWhen = strings.ToLower(b.UseResourceCacheWhen)
+	when := b.UseResourceCacheWhen
+	if when != "never" && when != "always" && when != "fallback" {
+		b.UseResourceCacheWhen = "fallback"
+	}
+
+	return b
+}
+
 // Sitemap configures the sitemap to be generated.
 type Sitemap struct {
 	ChangeFreq string
diff --git a/config/commonConfig_test.go b/config/commonConfig_test.go
new file mode 100644
index 000000000..281d2b0b6
--- /dev/null
+++ b/config/commonConfig_test.go
@@ -0,0 +1,60 @@
+// Copyright 2020 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package config
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/gohugoio/hugo/common/herrors"
+
+	qt "github.com/frankban/quicktest"
+
+	"github.com/spf13/viper"
+)
+
+func TestBuild(t *testing.T) {
+	c := qt.New(t)
+
+	v := viper.New()
+	v.Set("build", map[string]interface{}{
+		"useResourceCacheWhen": "always",
+	})
+
+	b := DecodeBuild(v)
+
+	c.Assert(b.UseResourceCacheWhen, qt.Equals, "always")
+
+	v.Set("build", map[string]interface{}{
+		"useResourceCacheWhen": "foo",
+	})
+
+	b = DecodeBuild(v)
+
+	c.Assert(b.UseResourceCacheWhen, qt.Equals, "fallback")
+
+	c.Assert(b.UseResourceCache(herrors.ErrFeatureNotAvailable), qt.Equals, true)
+	c.Assert(b.UseResourceCache(errors.New("err")), qt.Equals, false)
+
+	b.UseResourceCacheWhen = "always"
+	c.Assert(b.UseResourceCache(herrors.ErrFeatureNotAvailable), qt.Equals, true)
+	c.Assert(b.UseResourceCache(errors.New("err")), qt.Equals, true)
+	c.Assert(b.UseResourceCache(nil), qt.Equals, true)
+
+	b.UseResourceCacheWhen = "never"
+	c.Assert(b.UseResourceCache(herrors.ErrFeatureNotAvailable), qt.Equals, false)
+	c.Assert(b.UseResourceCache(errors.New("err")), qt.Equals, false)
+	c.Assert(b.UseResourceCache(nil), qt.Equals, false)
+
+}