go-blockchain, v1.3.1

The library that implements models and algorithms of blockchain.

Add the memory loader; restrict the cache size in the memoizing loader; optimize the memory storage; replace the blockchain.Hasher interface to the fmt.Stringer interface; return the errors from the proofers; split the code to the additional packages.

Change Log

models:
- block group loaders:
  - wrappers:
    - memoizing loader:
      - restricts the quantity of the remembered block groups:
        
        stores the loaded block groups in the LRU cache;
  - kinds:
    - memory loader:
      - loading blocks from the block group;
additionally:
- replace the blockchain.Hasher interface to the fmt.Stringer interface;
- return the error instead of a boolean flag from the blockchain.Proofer.Validate() method;
- add the packages:
  - storing;
  - loading;
- optimize the storages.MemoryStorage structure:
  - revert the use of the container/heap package;
  - optimize the detection of the last block;
  - optimize the sorting of the stored blocks;
- examples:
  - fix the examples in the README.md file;
  - improve the example with the loading of the blocks.

Features

models:
- block:
  - storing:
    - timestamp;
    - custom data;
    - hash;
    - previous hash;
  - operations:
    - creation (using a proofer);
    - getting merged data;
    - self-validation (using a proofer);
- genesis block:
  - based on a usual block without a previous hash;
- block group:
  - storing:
    - group of blocks;
  - operations:
    - self-validation (using a proofer):
      - modes:
        
        as a full blockchain;
        
        as a blockchain chunk;
      - takes into account a prepended chunk;
      - allows empty block groups;
    - validation of the last block (using a proofer):
      - modes:
        
        as a full blockchain;
        
        as a blockchain chunk;
- block group loaders:
  - loading block groups via the external interface;
  - automatically saving the loaded block groups to a storage;
  - wrappers:
    - chunk validating loader:
      - automatically validates the loaded block group as a blockchain chunk;
    - last block validating loader:
      - automatically validates the last block from the loaded block group;
      - automatically preloads the next block group to perform the above validation;
    - memoizing loader:
      - remembers loaded block groups;
      - restricts the quantity of the remembered block groups:
        
        stores the loaded block groups in the LRU cache;
  - kinds:
    - memory loader:
      - loading blocks from the block group;
- blockchain:
  - storing:
    - storage;
    - last block;
  - operations:
    - creation:
      - loading the last block from the storage;
      - when the storage is empty:
        
        creation a genesis block using a proofer;
        
        storing the genesis block to the storage;
    - adding a block:
      - creation a block using a proofer;
      - storing the block to the storage;
proofers:
- operations:
  - block hashing;
  - block validation;
- kinds:
  - simple:
    - based on once hashing by the SHA-256 algorithm;
  - proof of work:
    - based on the Hashcash algorithm;
    - additional storing in a block (in a hash actually):
      - nonce;
      - target bit;
storages:
- operations:
  - loading the last block;
  - storing a block;
  - storing a block group (optional);
- wrappers:
  - wrapper that adds support for saving a block group to those storages that cannot do this;
- kinds:
  - memory storage:
    - storing blocks in memory;
    - additional operations:
      - getting the stored blocks.

Examples

loading.LoadStorage:

package main

import (
    "encoding/json"
    "fmt"
    "log"
    "time"

    "github.com/thewizardplusplus/go-blockchain"
    "github.com/thewizardplusplus/go-blockchain/loading"
    "github.com/thewizardplusplus/go-blockchain/loading/loaders"
    "github.com/thewizardplusplus/go-blockchain/proofers"
    "github.com/thewizardplusplus/go-blockchain/storing"
    "github.com/thewizardplusplus/go-blockchain/storing/storages"
)

type StringData string

func (data StringData) String() string {
    return string(data)
}

type LoggingLoader struct {
    Loader blockchain.Loader
}

func (loader LoggingLoader) LoadBlocks(cursor interface{}, count int) (
    blocks blockchain.BlockGroup,
    nextCursor interface{},
    err error,
) {
    fmt.Printf("[DEBUG] load the blocks corresponding to cursor %v\n", cursor)

    return loader.Loader.LoadBlocks(cursor, count)
}

func main() {
    timestamp := time.Date(2006, time.January, 2, 15, 4, 5, 0, time.UTC)
    blocks := blockchain.BlockGroup{
        {
            Timestamp: timestamp.Add(6 * time.Hour),
            Data:      StringData("block #4"),
            Hash: "248:" +
                "173:" +
                "00b6863763acd6ec77ca3521589d8e68c118efe855657d702783e8e6aee169a9",
            PrevHash: "248:" +
                "65:" +
                "00d5800e119abe44d89469c2161be7f9645d7237697c6d14b4a72717893582fa",
        },
        {
            Timestamp: timestamp.Add(5 * time.Hour),
            Data:      StringData("block #3"),
            Hash: "248:" +
                "65:" +
                "00d5800e119abe44d89469c2161be7f9645d7237697c6d14b4a72717893582fa",
            PrevHash: "248:" +
                "136:" +
                "003c7def3d467a759fad481c03cadbd62e62b2c5dbc10e4bbb6e1944c158a8be",
        },
        {
            Timestamp: timestamp.Add(4 * time.Hour),
            Data:      StringData("block #2"),
            Hash: "248:" +
                "136:" +
                "003c7def3d467a759fad481c03cadbd62e62b2c5dbc10e4bbb6e1944c158a8be",
            PrevHash: "248:" +
                "15:" +
                "002fc891ad012c4a89f7b267a2ec1767415c627ff69b88b90a93be938b026efa",
        },
        {
            Timestamp: timestamp.Add(3 * time.Hour),
            Data:      StringData("block #1"),
            Hash: "248:" +
                "15:" +
                "002fc891ad012c4a89f7b267a2ec1767415c627ff69b88b90a93be938b026efa",
            PrevHash: "248:" +
                "198:" +
                "0058f5dae6ca3451801a276c94862c7cce085e6f9371e50d80ddbb87c1438faf",
        },
        {
            Timestamp: timestamp.Add(2 * time.Hour),
            Data:      StringData("block #0"),
            Hash: "248:" +
                "198:" +
                "0058f5dae6ca3451801a276c94862c7cce085e6f9371e50d80ddbb87c1438faf",
            PrevHash: "248:" +
                "225:" +
                "00e26abd9974fcdea4b32eca43c9dc5c67fffa8efd53cebffa9b049fd6c2bb36",
        },
        {
            Timestamp: timestamp.Add(time.Hour),
            Data:      StringData("genesis block"),
            Hash: "248:" +
                "225:" +
                "00e26abd9974fcdea4b32eca43c9dc5c67fffa8efd53cebffa9b049fd6c2bb36",
            PrevHash: "",
        },
    }

    blockDependencies := blockchain.BlockDependencies{
        Proofer: proofers.ProofOfWork{TargetBit: 248},
    }

    var storage storages.MemoryStorage
    if _, err := loading.LoadStorage(
        storing.NewGroupStorage(&storage),
        loading.LastBlockValidatingLoader{
            Loader: loading.NewMemoizingLoader(1, loading.ChunkValidatingLoader{
                Loader: LoggingLoader{
                    Loader: loaders.MemoryLoader(blocks),
                },
                Dependencies: blockDependencies,
            }),
            Dependencies: blockDependencies,
        },
        nil,
        2,
    ); err != nil {
        log.Fatalf("unable to load the blocks: %v", err)
    }

    blocksBytes, _ := json.MarshalIndent(storage.Blocks(), "", "  ")
    fmt.Println(string(blocksBytes))

    // Output:
    // [DEBUG] load the blocks corresponding to cursor <nil>
    // [DEBUG] load the blocks corresponding to cursor 2
    // [DEBUG] load the blocks corresponding to cursor 4
    // [DEBUG] load the blocks corresponding to cursor 6
    // [
    //   {
    //     "Timestamp": "2006-01-02T16:04:05Z",
    //     "Data": "genesis block",
    //     "Hash": "248:225:00e26abd9974fcdea4b32eca43c9dc5c67fffa8efd53cebffa9b049fd6c2bb36",
    //     "PrevHash": ""
    //   },
    //   {
    //     "Timestamp": "2006-01-02T17:04:05Z",
    //     "Data": "block #0",
    //     "Hash": "248:198:0058f5dae6ca3451801a276c94862c7cce085e6f9371e50d80ddbb87c1438faf",
    //     "PrevHash": "248:225:00e26abd9974fcdea4b32eca43c9dc5c67fffa8efd53cebffa9b049fd6c2bb36"
    //   },
    //   {
    //     "Timestamp": "2006-01-02T18:04:05Z",
    //     "Data": "block #1",
    //     "Hash": "248:15:002fc891ad012c4a89f7b267a2ec1767415c627ff69b88b90a93be938b026efa",
    //     "PrevHash": "248:198:0058f5dae6ca3451801a276c94862c7cce085e6f9371e50d80ddbb87c1438faf"
    //   },
    //   {
    //     "Timestamp": "2006-01-02T19:04:05Z",
    //     "Data": "block #2",
    //     "Hash": "248:136:003c7def3d467a759fad481c03cadbd62e62b2c5dbc10e4bbb6e1944c158a8be",
    //     "PrevHash": "248:15:002fc891ad012c4a89f7b267a2ec1767415c627ff69b88b90a93be938b026efa"
    //   },
    //   {
    //     "Timestamp": "2006-01-02T20:04:05Z",
    //     "Data": "block #3",
    //     "Hash": "248:65:00d5800e119abe44d89469c2161be7f9645d7237697c6d14b4a72717893582fa",
    //     "PrevHash": "248:136:003c7def3d467a759fad481c03cadbd62e62b2c5dbc10e4bbb6e1944c158a8be"
    //   },
    //   {
    //     "Timestamp": "2006-01-02T21:04:05Z",
    //     "Data": "block #4",
    //     "Hash": "248:173:00b6863763acd6ec77ca3521589d8e68c118efe855657d702783e8e6aee169a9",
    //     "PrevHash": "248:65:00d5800e119abe44d89469c2161be7f9645d7237697c6d14b4a72717893582fa"
    //   }
    // ]
}

Repository

Link: https://github.com/thewizardplusplus/go-blockchain/tree/v1.3.1.

Content: code.

License: MIT.