Make IPFS feature opt-in

Signed-off-by: Kohei Tokunaga <[email protected]>

Author: ktock

docs/ipfs.md

@@ -2,6 +2,13 @@
 
 You can run OCI-compatible container images on IPFS with lazy pulling.
 
+Add the following configuration to `config.toml` of Stargz Snapsohtter (typically located at `/etc/containerd-stargz-grpc/config.toml`).
+
+```toml
+[blob]
+ipfs = true
+```
+
 ## IPFS-enabled OCI Image
 
 For obtaining IPFS-enabled OCI Image, each descriptor in an OCI image must contain the following URL in `urls` field.

fs/config/config.go

@@ -74,6 +74,9 @@ type BlobConfig struct {
 	MaxRetries  int `toml:"max_retries"`
 	MinWaitMSec int `toml:"min_wait_msec"`
 	MaxWaitMSec int `toml:"max_wait_msec"`
+
+	// IPFS is an option to allow snapshotter mounting layers from IPFS.
+	IPFS bool `toml:"ipfs"`
 }
 
 type DirectoryCacheConfig struct {

fs/remote/resolver.go

@@ -116,7 +116,7 @@ func (r *Resolver) Resolve(ctx context.Context, hosts source.RegistryHosts, refs
 
 	var f fetcher
 	var size int64
-	if ipfs.Supported(desc) {
+	if r.blobConfig.IPFS && ipfs.Supported(desc) {
 		r, s, err := ipfs.NewReader(ctx, desc)
 		if err != nil {
 			return nil, err

script/integration/containerd/config.stargz.toml

@@ -2,6 +2,7 @@ metadata_store = "memory"
 
 [blob]
 check_always = true
+ipfs = true
 
 [[resolver.host."registry-integration.test".mirrors]]
 host = "registry-alt.test:5000"