Add a consolidated file cache

This commits reworks how file caching is performed in Hugo. Now there is only one way, and it can be configured.

This is the default configuration:

```toml
[caches]
[caches.getjson]
dir = ":cacheDir"
maxAge = -1
[caches.getcsv]
dir = ":cacheDir"
maxAge = -1
[caches.images]
dir = ":resourceDir/_gen"
maxAge = -1
[caches.assets]
dir = ":resourceDir/_gen"
maxAge = -1
```

You can override any of these cache setting in your own `config.toml`.

The placeholders explained:

`:cacheDir`: This is the value of the `cacheDir` config option if set (can also be set via OS env variable `HUGO_CACHEDIR`). It will fall back to `/opt/build/cache/hugo_cache/` on Netlify, or a `hugo_cache` directory below the OS temp dir for the others.
`:resourceDir`: This is the value of the `resourceDir` config option.

`maxAge` is the time in seconds before a cache entry will be evicted, -1 means forever and 0 effectively turns that particular cache off.

This means that if you run your builds on Netlify, all caches configured with `:cacheDir` will be saved and restored on the next build. For other CI vendors, please read their documentation. For an CircleCI example, see https://github.com/bep/hugo-sass-test/blob/6c3960a8f4b90e8938228688bc49bdcdd6b2d99e/.circleci/config.yml

Fixes #5404

1 files changed, 9 insertions, 4 deletions

diff --git a/resource/testhelpers_test.go b/resource/testhelpers_test.go
index 2a5d2b3cd..05a02a6fc 100644
--- a/resource/testhelpers_test.go
+++ b/resource/testhelpers_test.go
@@ -13,6 +13,7 @@ import (
 	"runtime"
 	"strings"
 
+	"github.com/gohugoio/hugo/cache/filecache"
 	"github.com/gohugoio/hugo/helpers"
 	"github.com/gohugoio/hugo/hugofs"
 	"github.com/gohugoio/hugo/media"
@@ -49,10 +50,12 @@ func newTestResourceSpecForBaseURL(assert *require.Assertions, baseURL string) *
 	fs := hugofs.NewMem(cfg)
 
 	s, err := helpers.NewPathSpec(fs, cfg)
+	assert.NoError(err)
 
+	filecaches, err := filecache.NewCachesFromPaths(s.Paths)
 	assert.NoError(err)
 
-	spec, err := NewSpec(s, nil, output.DefaultFormats, media.DefaultTypes)
+	spec, err := NewSpec(s, filecaches, nil, output.DefaultFormats, media.DefaultTypes)
 	assert.NoError(err)
 	return spec
 }
@@ -70,7 +73,7 @@ func newTestResourceOsFs(assert *require.Assertions) *Spec {
 	}
 
 	cfg.Set("workingDir", workDir)
-	cfg.Set("resourceDir", filepath.Join(workDir, "res"))
+	cfg.Set("resourceDir", "resources")
 	cfg.Set("contentDir", "content")
 	cfg.Set("dataDir", "data")
 	cfg.Set("i18nDir", "i18n")
@@ -83,10 +86,12 @@ func newTestResourceOsFs(assert *require.Assertions) *Spec {
 	fs.Destination = &afero.MemMapFs{}
 
 	s, err := helpers.NewPathSpec(fs, cfg)
+	assert.NoError(err)
 
+	filecaches, err := filecache.NewCachesFromPaths(s.Paths)
 	assert.NoError(err)
 
-	spec, err := NewSpec(s, nil, output.DefaultFormats, media.DefaultTypes)
+	spec, err := NewSpec(s, filecaches, nil, output.DefaultFormats, media.DefaultTypes)
 	assert.NoError(err)
 	return spec
 
@@ -144,7 +149,7 @@ func assertImageFile(assert *require.Assertions, fs afero.Fs, filename string, w
 }
 
 func assertFileCache(assert *require.Assertions, fs afero.Fs, filename string, width, height int) {
-	assertImageFile(assert, fs, filepath.Join("_gen/images", filename), width, height)
+	assertImageFile(assert, fs, filepath.Clean(filename), width, height)
 }
 
 func writeSource(t testing.TB, fs *hugofs.Fs, filename, content string) {