adaptation: implement wrapper for old plugins.

Add a backward compatibility wrapper for old plugins which do not
support the full set of dedicated lifecycle events yet. Fall back
to relaying StateChange events to them.

Record deprecation warnings for each unimplemented new plugin
interface where we need to fall back and funnel calls through
the old StateChange RPC call.

Signed-off-by: Krisztian Litkey <krisztian.litkey@intel.com>

Author: klihub

pkg/adaptation/adaptation.go

@@ -76,6 +76,7 @@ type Adaptation struct {
 	syncLock    sync.RWMutex
 	wasmService *api.PluginPlugin
 	metrics     Metrics
+	deprecation DeprecationRecorder
 }
 
 var (
@@ -158,6 +159,15 @@ func WithDefaultValidator(cfg *validator.DefaultValidatorConfig) Option {
 	}
 }
 
+// WithDeprecationRecorder sets up functions to record usage of deprecated
+// NRI interfaces or features.
+func WithDeprecationRecorder(d DeprecationRecorder) Option {
+	return func(r *Adaptation) error {
+		r.deprecation = d
+		return nil
+	}
+}
+
 // New creates a new NRI Runtime.
 func New(name, version string, syncFn SyncFn, updateFn UpdateFn, opts ...Option) (*Adaptation, error) {
 	var err error

pkg/adaptation/api.go

@@ -109,6 +109,7 @@ type (
 	SecurityProfile          = api.SecurityProfile
 	User                     = api.User
 
+	Event     = api.Event
 	EventMask = api.EventMask
 )
 

pkg/adaptation/deprecations.go

@@ -0,0 +1,46 @@
+/*
+   Copyright The containerd Authors.
+
+   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 adaptation
+
+import (
+	"context"
+	"fmt"
+)
+
+// DeprecationRecorder is the interface for recording NRI deprecation warnings.
+type DeprecationRecorder interface {
+	// PluginWarning records a warning for a plugin.
+	PluginWarning(ctx context.Context, d Deprecation, plugin, details string)
+}
+
+// Deprecation is the type for NRI deprecations.
+type Deprecation int
+
+const (
+	// DeprecatedStateChange indicates that a plugin does not implement per
+	// request RPC calls, using the deprecated StateChange instead.
+	DeprecatedStateChange Deprecation = iota + 1
+)
+
+func (d Deprecation) String() string {
+	switch d {
+	case DeprecatedStateChange:
+		return "deprecated StateChange"
+	default:
+		return fmt.Sprintf("unknown deprecation (%d)", d)
+	}
+}

pkg/adaptation/plugin.go

@@ -629,6 +629,7 @@ func (p *plugin) runPodSandbox(ctx context.Context, req *RunPodSandboxRequest) (
 		}
 		return nil, err
 	}
+	p.warnDeprecatedEvent(ctx, event)
 
 	return rpl, nil
 }
@@ -681,6 +682,7 @@ func (p *plugin) postUpdatePodSandbox(ctx context.Context, req *PostUpdatePodSan
 		}
 		return nil, err
 	}
+	p.warnDeprecatedEvent(ctx, event)
 
 	return &PostUpdatePodSandboxResponse{}, nil
 }
@@ -707,6 +709,7 @@ func (p *plugin) stopPodSandbox(ctx context.Context, req *StopPodSandboxRequest)
 		}
 		return nil, err
 	}
+	p.warnDeprecatedEvent(ctx, event)
 
 	return &StopPodSandboxResponse{}, nil
 }
@@ -733,6 +736,7 @@ func (p *plugin) removePodSandbox(ctx context.Context, req *RemovePodSandboxRequ
 		}
 		return nil, err
 	}
+	p.warnDeprecatedEvent(ctx, event)
 
 	return &RemovePodSandboxResponse{}, nil
 }
@@ -788,6 +792,7 @@ func (p *plugin) postCreateContainer(ctx context.Context, req *PostCreateContain
 		}
 		return nil, err
 	}
+	p.warnDeprecatedEvent(ctx, event)
 
 	return &PostCreateContainerResponse{}, nil
 }
@@ -814,6 +819,7 @@ func (p *plugin) startContainer(ctx context.Context, req *StartContainerRequest)
 		}
 		return nil, err
 	}
+	p.warnDeprecatedEvent(ctx, event)
 
 	return &StartContainerResponse{}, nil
 }
@@ -840,6 +846,7 @@ func (p *plugin) postStartContainer(ctx context.Context, req *PostStartContainer
 		}
 		return nil, err
 	}
+	p.warnDeprecatedEvent(ctx, event)
 
 	return &PostStartContainerResponse{}, nil
 }
@@ -895,6 +902,7 @@ func (p *plugin) postUpdateContainer(ctx context.Context, req *PostUpdateContain
 		}
 		return nil, err
 	}
+	p.warnDeprecatedEvent(ctx, event)
 
 	return &PostUpdateContainerResponse{}, nil
 }
@@ -950,6 +958,7 @@ func (p *plugin) removeContainer(ctx context.Context, req *RemoveContainerReques
 		}
 		return nil, err
 	}
+	p.warnDeprecatedEvent(ctx, event)
 
 	return &RemoveContainerResponse{}, nil
 }
@@ -990,6 +999,25 @@ func (p *plugin) recordAdjustments(op string, adjust *ContainerAdjustment, updat
 	p.r.metrics.RecordPluginAdjustments(p.name(), op, adjust, updates, evicts)
 }
 
+// Warn about a plugins using deprecated StateChange for event handling.
+func (p *plugin) warnDeprecatedEvent(ctx context.Context, event Event) {
+	if !p.impl.deprecated[event] || p.impl.warned[event] {
+		return
+	}
+
+	if p.r.deprecation != nil {
+		p.r.deprecation.PluginWarning(ctx, DeprecatedStateChange, p.name(),
+			fmt.Sprintf("does not implement a dedicated %s RPC call", event.PrettyName()))
+	} else {
+		log.Warnf(ctx, "plugin %s uses deprecated StateChange instead of a dedicated %s RPC call",
+			p.name(), event.PrettyName())
+		log.Warnf(ctx, "please update %s with a newer version of NRI for future compatibility",
+			p.name())
+	}
+
+	p.impl.warned[event] = true
+}
+
 // isFatalError returns true if the error is fatal and the plugin connection should be closed.
 func isFatalError(err error) bool {
 	switch {
@@ -1001,8 +1029,6 @@ func isFatalError(err error) bool {
 		return true
 	case errors.Is(err, context.DeadlineExceeded):
 		return true
-	case status.Code(err) == codes.Unimplemented:
-		return true
 	}
 	return false
 }