dynamo/deploy/operator/internal/checkpoint/hash.go

99 lines
3.4 KiB
Go

/*
* SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
* SPDX-License-Identifier: Apache-2.0
*
* 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 checkpoint
import (
"crypto/sha256"
"encoding/hex"
"encoding/json"
"fmt"
nvidiacomv1alpha1 "github.com/ai-dynamo/dynamo/deploy/operator/api/v1alpha1"
)
// normalizedIdentity is the canonical form used for hash computation
// Only fields that affect checkpoint equivalence are included
type normalizedIdentity struct {
Model string `json:"model"`
BackendFramework string `json:"backendFramework"`
DynamoVersion string `json:"dynamoVersion,omitempty"`
TensorParallelSize int32 `json:"tensorParallelSize"`
PipelineParallelSize int32 `json:"pipelineParallelSize"`
Dtype string `json:"dtype,omitempty"`
MaxModelLen int32 `json:"maxModelLen,omitempty"`
ExtraParameters map[string]string `json:"extraParameters,omitempty"`
}
// ComputeIdentityHash computes a deterministic hash from a DynamoCheckpointIdentity
// The hash is computed by:
// 1. Normalizing all fields
// 2. Serializing to JSON (with sorted keys)
// 3. Computing SHA256 hash
// 4. Returning first 16 characters of hex encoding (64 bits)
//
// 16 hex characters (64 bits) provides excellent collision resistance:
// - 1% collision probability at ~500 million configs
// - 50% collision probability at ~4 billion configs
// This is a perfect balance between readability and safety.
func ComputeIdentityHash(identity nvidiacomv1alpha1.DynamoCheckpointIdentity) (string, error) {
normalized := normalizeIdentity(identity)
// Serialize to JSON (Go's json.Marshal sorts map keys)
data, err := json.Marshal(normalized)
if err != nil {
// This should never happen with our controlled types, but bubble up error if it does
return "", fmt.Errorf("failed to marshal identity for hashing: %w", err)
}
// Compute SHA256 hash
hash := sha256.Sum256(data)
// Return first 16 characters of hex encoding (64 bits)
// Provides excellent collision resistance while remaining readable
return hex.EncodeToString(hash[:])[:16], nil
}
func normalizeIdentity(identity nvidiacomv1alpha1.DynamoCheckpointIdentity) normalizedIdentity {
// Apply defaults for TP/PP if not set
tp := identity.TensorParallelSize
if tp == 0 {
tp = 1
}
pp := identity.PipelineParallelSize
if pp == 0 {
pp = 1
}
// ExtraParameters - ensure non-nil for consistent JSON
extraParams := identity.ExtraParameters
if extraParams == nil {
extraParams = make(map[string]string)
}
return normalizedIdentity{
Model: identity.Model,
BackendFramework: identity.BackendFramework,
DynamoVersion: identity.DynamoVersion,
TensorParallelSize: tp,
PipelineParallelSize: pp,
Dtype: identity.Dtype,
MaxModelLen: identity.MaxModelLen,
ExtraParameters: extraParams,
}
}