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yuuichi fujioka
yuuichi fujioka

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I thought LevelDB is a good one, so I made client command with Go.

Suddenly, I looked for KVS that can be used as a library like SQLite and found it in LevelDB.

GitHub logo google / leveldb

LevelDB is a fast key-value storage library written at Google that provides an ordered mapping from string keys to string values.

LevelDB is a fast key-value storage library written at Google that provides an ordered mapping from string keys to string values.

Build Status Build status

Authors: Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)

Features

  • Keys and values are arbitrary byte arrays.
  • Data is stored sorted by key.
  • Callers can provide a custom comparison function to override the sort order.
  • The basic operations are Put(key,value), Get(key), Delete(key).
  • Multiple changes can be made in one atomic batch.
  • Users can create a transient snapshot to get a consistent view of data.
  • Forward and backward iteration is supported over the data.
  • Data is automatically compressed using the Snappy compression library.
  • External activity (file system operations etc.) is relayed through a virtual interface so users can customize the operating system interactions.

Documentation

LevelDB library documentation is online and bundled with the source code.

Limitations

  • This is not a SQL database. It…

It was a pleasure to use plyvel of Python's LevelDB library, but I decided to create a client command because I don't want to not write Python every time to retrieve a list or list of keys or to delete unnecessary keys.

And here is the one.

GitHub logo yuuichi-fujioka / go-leveldbctl

LevelDB control command

leveldbctl

Build Status Coverage Status

LevelDB control command.

This command provides easy way to CRUD operation on LevelDB.

$ leveldbctl put foo bar
put foo: bar into ./
$ leveldbctl get foo
bar
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Features

  • Initialize LevelDB
  • Put key/value into LevelDB
  • Get value with key
  • Delete key
  • Dump all key/values in LevelDB
  • Print all keys

Install

$ export GO111MODULE=on
$ go get github.com/yuuichi-fujioka/go-leveldbctl/cmd/leveldbctl
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Usage

NAME
   leveldbctl - A new cli application
USAGE
   leveldbctl [global options] command [command options] [arguments...]

VERSION:
   0.0.0

COMMANDS:
     init, i    Initialize a LevelDB
     walk, w    Walk in a LevelDB
     keys, k    Search all keys in a LevelDB
     put, p     Put a value into a LevelDB
     get, g     Gut a value from a LevelDB
     delete, d  Delete a value from a LevelDB
     help, h    Shows a list of commands or help for one command

GLOBAL OPTIONS:
   --dbdir value, -d value  LevelDB Directory (default: "./") [$LEVELDB_DIR]
   --hexkey, --xk
…
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It can be used by installing with go get.

$ go get github.com/yuuichi-fujioka/go-leveldbctl/cmd/leveldbctl
$ leveldbctl -h
NAME:
   leveldbctl - A new cli application

USAGE:
   leveldbctl [global options] command [command options] [arguments...]

VERSION:
   0.0.0

COMMANDS:
     init, i    Initialize a LevelDB
     walk, w    Walk in a LevelDB
     keys, k    Search all keys in a LevelDB
     put, p     Put a value into a LevelDB
     get, g     Gut a value from a LevelDB
     delete, d  Delete a value from a LevelDB
     help, h    Shows a list of commands or help for one command

GLOBAL OPTIONS:
   --dbdir value, -d value  LevelDB Directory (default: "./") [$LEVELDB_DIR]
   --help, -h               show help
   --version, -v            print the version
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How to Use

It can initialize and CRUD operation, assuming that the current directory is a directory of LevelDB. (Specific directories may be set as LevelDB with the options --dbdir or -d)

Initialize with init, make it with put, get it with get, delete it with delete.

$ leveldbctl init   #  Initialize. Several files are created.
./ is initialized as LevelDB
$ leveldbctl get aaa  # When a key is not exist in db, it is displayed that it cannot be found.
aaa is not found.
$ leveldbctl put aaa bbb  # Put bbb into aaa.
put aaa: bbb into ./.
$ leveldbctl get aaa  # Got bbb
bbb
$ leveldbctl delete aaa  # Delete it.
aaa is deleted
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walk can output all key values,keys can output all keys.

$ leveldbctl keys
egg
foo
hoge
$ leveldbctl walk
egg: spam
foo: bar
hoge: fuga
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Misc

  • I tested it On Mac OS High Sierra and Ubuntu 16.04.4 LTS.。
  • CLI is implemented using github.com/urfave/cli.
  • LevelDB operation uses github.com/syndtr/goleveldb/leveldb.

Top comments (2)

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tschellenbach profile image
Thierry

Did you try RocksDB? It's been working wonders for us.

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yuuichifujioka profile image
yuuichi fujioka

Thank you! I will try it.

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