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, 14 insertions, 2 deletions

diff --git a/deps/deps.go b/deps/deps.go
index db59ad212..a1b54a862 100644
--- a/deps/deps.go
+++ b/deps/deps.go
@@ -4,6 +4,9 @@ import (
 	"sync"
 	"time"
 
+	"github.com/pkg/errors"
+
+	"github.com/gohugoio/hugo/cache/filecache"
 	"github.com/gohugoio/hugo/common/loggers"
 	"github.com/gohugoio/hugo/config"
 	"github.com/gohugoio/hugo/helpers"
@@ -53,6 +56,9 @@ type Deps struct {
 	// The configuration to use
 	Cfg config.Provider `json:"-"`
 
+	// The file cache to use.
+	FileCaches filecache.Caches
+
 	// The translation func to use
 	Translate func(translationID string, args ...interface{}) string `json:"-"`
 
@@ -187,7 +193,12 @@ func New(cfg DepsCfg) (*Deps, error) {
 		return nil, err
 	}
 
-	resourceSpec, err := resource.NewSpec(ps, logger, cfg.OutputFormats, cfg.MediaTypes)
+	fileCaches, err := filecache.NewCachesFromPaths(ps.Paths)
+	if err != nil {
+		return nil, errors.WithMessage(err, "failed to create file caches from configuration")
+	}
+
+	resourceSpec, err := resource.NewSpec(ps, fileCaches, logger, cfg.OutputFormats, cfg.MediaTypes)
 	if err != nil {
 		return nil, err
 	}
@@ -219,6 +230,7 @@ func New(cfg DepsCfg) (*Deps, error) {
 		ResourceSpec:        resourceSpec,
 		Cfg:                 cfg.Language,
 		Language:            cfg.Language,
+		FileCaches:          fileCaches,
 		BuildStartListeners: &Listeners{},
 		Timeout:             time.Duration(timeoutms) * time.Millisecond,
 		globalErrHandler:    &globalErrHandler{},
@@ -250,7 +262,7 @@ func (d Deps) ForLanguage(cfg DepsCfg) (*Deps, error) {
 	// The resource cache is global so reuse.
 	// TODO(bep) clean up these inits.
 	resourceCache := d.ResourceSpec.ResourceCache
-	d.ResourceSpec, err = resource.NewSpec(d.PathSpec, d.Log, cfg.OutputFormats, cfg.MediaTypes)
+	d.ResourceSpec, err = resource.NewSpec(d.PathSpec, d.ResourceSpec.FileCaches, d.Log, cfg.OutputFormats, cfg.MediaTypes)
 	if err != nil {
 		return nil, err
 	}