5 files changed, 31 insertions, 19 deletions
diff --git a/cache/filecache/filecache.go b/cache/filecache/filecache.go
index c6ea02681..da0a90d57 100644
--- a/cache/filecache/filecache.go
+++ b/cache/filecache/filecache.go
@@ -36,8 +36,9 @@ import (
 type Cache struct {
 	Fs afero.Fs
 
-	// Max age in seconds.
-	maxAge int
+	// Max age for items in this cache. Negative duration means forever,
+	// 0 is effectively turning this cache off.
+	maxAge time.Duration
 
 	nlocker *locker.Locker
 }
@@ -49,7 +50,7 @@ type ItemInfo struct {
 }
 
 // NewCache creates a new file cache with the given filesystem and max age.
-func NewCache(fs afero.Fs, maxAge int) *Cache {
+func NewCache(fs afero.Fs, maxAge time.Duration) *Cache {
 	return &Cache{
 		Fs:      fs,
 		nlocker: locker.NewLocker(),
@@ -227,9 +228,7 @@ func (c *Cache) getOrRemove(id string) hugio.ReadSeekCloser {
 			return nil
 		}
 
-		expiry := time.Now().Add(-time.Duration(c.maxAge) * time.Second)
-		expired := fi.ModTime().Before(expiry)
-		if expired {
+		if time.Now().Sub(fi.ModTime()) > c.maxAge {
 			c.Fs.Remove(id)
 			return nil
 		}
diff --git a/cache/filecache/filecache_config.go b/cache/filecache/filecache_config.go
index f83e19e0e..9913fd7e2 100644
--- a/cache/filecache/filecache_config.go
+++ b/cache/filecache/filecache_config.go
@@ -17,6 +17,7 @@ import (
 	"path"
 	"path/filepath"
 	"strings"
+	"time"
 
 	"github.com/gohugoio/hugo/helpers"
 	"github.com/gohugoio/hugo/hugolib/paths"
@@ -62,8 +63,8 @@ type cachesConfig map[string]cacheConfig
 type cacheConfig struct {
 	// Max age of cache entries in this cache. Any items older than this will
 	// be removed and not returned from the cache.
-	// -1 means forever, 0 means cache is disabled.
-	MaxAge int
+	// a negative value means forever, 0 means cache is disabled.
+	MaxAge time.Duration
 
 	// The directory where files are stored.
 	Dir string
@@ -107,7 +108,18 @@ func decodeConfig(p *paths.Paths) (cachesConfig, error) {
 	for k, v := range m {
 		cc := defaultCacheConfig
 
-		if err := mapstructure.WeakDecode(v, &cc); err != nil {
+		dc := &mapstructure.DecoderConfig{
+			Result:           &cc,
+			DecodeHook:       mapstructure.StringToTimeDurationHookFunc(),
+			WeaklyTypedInput: true,
+		}
+
+		decoder, err := mapstructure.NewDecoder(dc)
+		if err != nil {
+			return c, err
+		}
+
+		if err := decoder.Decode(v); err != nil {
 			return nil, err
 		}
 
diff --git a/cache/filecache/filecache_config_test.go b/cache/filecache/filecache_config_test.go
index 209be823d..22fb1b56b 100644
--- a/cache/filecache/filecache_config_test.go
+++ b/cache/filecache/filecache_config_test.go
@@ -17,6 +17,7 @@ import (
 	"path/filepath"
 	"runtime"
 	"testing"
+	"time"
 
 	"github.com/gohugoio/hugo/config"
 	"github.com/gohugoio/hugo/hugofs"
@@ -34,10 +35,10 @@ func TestDecodeConfig(t *testing.T) {
 	configStr := `
 [caches]
 [caches.getJSON]
-maxAge = 1234
+maxAge = "10m"
 dir = "/path/to/c1"
 [caches.getCSV]
-maxAge = 3456
+maxAge = "11h"
 dir = "/path/to/c2"
 [caches.images]
 dir = "/path/to/c3"
@@ -56,11 +57,11 @@ dir = "/path/to/c3"
 	assert.Equal(4, len(decoded))
 
 	c2 := decoded["getcsv"]
-	assert.Equal(3456, c2.MaxAge)
+	assert.Equal("11h0m0s", c2.MaxAge.String())
 	assert.Equal(filepath.FromSlash("/path/to/c2"), c2.Dir)
 
 	c3 := decoded["images"]
-	assert.Equal(-1, c3.MaxAge)
+	assert.Equal(time.Duration(-1), c3.MaxAge)
 	assert.Equal(filepath.FromSlash("/path/to/c3"), c3.Dir)
 
 }
@@ -96,7 +97,7 @@ dir = "/path/to/c3"
 	assert.Equal(4, len(decoded))
 
 	for _, v := range decoded {
-		assert.Equal(0, v.MaxAge)
+		assert.Equal(time.Duration(0), v.MaxAge)
 	}
 
 }
diff --git a/cache/filecache/filecache_test.go b/cache/filecache/filecache_test.go
index 4f5336be5..b3b8376ed 100644
--- a/cache/filecache/filecache_test.go
+++ b/cache/filecache/filecache_test.go
@@ -44,7 +44,7 @@ func TestFileCache(t *testing.T) {
 cacheDir = "CACHEDIR"
 [caches]
 [caches.getJSON]
-maxAge = 111
+maxAge = "10h"
 dir = ":cacheDir/c"
 
 `
@@ -62,7 +62,7 @@ dir = ":cacheDir/c"
 
 		c := caches.Get("GetJSON")
 		assert.NotNil(c)
-		assert.Equal(111, c.maxAge)
+		assert.Equal("10h0m0s", c.maxAge.String())
 
 		bfs, ok := c.Fs.(*afero.BasePathFs)
 		assert.True(ok)
@@ -151,7 +151,7 @@ func TestFileCacheConcurrent(t *testing.T) {
 	configStr := `
 [caches]
 [caches.getjson]
-maxAge = 1
+maxAge = "1s"
 dir = "/cache/c"
 
 `
diff --git a/docs/content/en/getting-started/configuration.md b/docs/content/en/getting-started/configuration.md
index de978f510..cb2eed4cd 100644
--- a/docs/content/en/getting-started/configuration.md
+++ b/docs/content/en/getting-started/configuration.md
@@ -439,8 +439,8 @@ You can override any of these cache setting in your own `config.toml`.
 : This is the value of the `resourceDir` config option.
 
 maxAge
-: This is the time in seconds before a cache entry will be evicted, -1 means forever and 0 effectively turns that particular cache off.
-
+: This is the duration before a cache entry will be evicted, -1 means forever and 0 effectively turns that particular cache off. Uses Go's `time.Duration`, so valid values are `"10s"` (10 seconds), `"10m"` (10 minutes) and `"10m"` (10 hours).
+ 
 dir
 : The absolute path to where the files for this cache will be stored. Allowed starting placeholders are `:cacheDir` and `:resourceDir` (see above).