Awesome
lev2
A CLI and a REPL for managing LevelDB
instances.
This repo is a fork of lev
, originally to make those changes available from NPM
Features
- CLI
- providing many basic tools to read and write on a leveldb from the command line
- import / export, and delete by range
- REPL
- with colorized tab-completion and zsh/fish style key suggestions
- automatically saves and reloads REPL history
Summary
<!-- START doctoc generated TOC please keep comment here to allow auto update --> <!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE --> <!-- END doctoc generated TOC please keep comment here to allow auto update -->Installation
$ npm install -g lev2
CLI
These all match the parameters used with levelup
. The default encoding for the database is set to json
.
--get <key>
Get a value
lev --get foo
--put <key>
Put a value
lev --put foo --value bar
--del <key>
Delete a value
lev --del foo
Can be used in combination with --keys
, or --all
, or implicit --all
, to generate a stream of delete operations to be passed to the lev --batch
command
lev --keys --del | lev --batch
lev --all --del | lev --batch
lev --gte abc --lte abd --del | lev --batch
--batch <operations>
Put or delete several values, using levelup
batch syntax
lev --batch '[
{"type":"del","key":"a"},
{"type":"put","key":"b","value":"123"},
{"type":"put","key":"c","value":"456"}
]'
or from a file
# there should be one entry per line
# either as valid JSON
echo '[
{"type":"del","key":"a"},
{"type":"put","key":"b","value":"123"},
{"type":"put","key":"c","value":"456"}
]' > ops.json
# or as newline-delimited JSON
echo '
{"type":"del","key":"a"}
{"type":"put","key":"b","value":"123"}
{"type":"put","key":"c","value":"456"}
' > ops.json
lev --batch ./operations.json
Import / Export
If the type is omitted, defaults to put
, which allows to use the command to do imports/exports, in combination with --all
:
# export
lev --all > leveldb.export
# import
lev /tmp/my-new-db --batch leveldb.export
If it's a large export, you can use compress it on the fly
# export
lev --all | gzip -9 > leveldb.export.gz
# import
gzip -d < leveldb.export.gz | lev /tmp/my-new-db --batch
Bulk delete
The --batch
option can also be used to delete key/values by range in 2 steps:
# 1 - collect all the key to delete
lev --prefix 'foo' --del > ./deletion_operations
# 2 - pass the file as argument to the --batch option
lev --batch ./deletion_operations
The same can be done with --match
lev --match '*foo*' --del > ./deletion_operations
--keys
List all the keys in the current range
lev --keys
Can be used in combination with --del
to generate a stream of delete operations
lev --keys --del | lev --batch
--values
List all the values in the current range. Emit as a new-line delimited stream of json.
lev --values
--all
List all the keys and values in the current range. Emit as a new-line delimited stream of json.
lev --all
It can be used to create an export of the database, to be imported with --batch
lev --all > leveldb.export
lev /tmp/my-new-db --batch leveldb.export
It can be used in combinaision with other options, but can then also be omitted as its the default stream mode
lev --all --prefix 'foo'
# is equivalent to
lev --prefix 'foo'
--gte <key-pattern>
Start the range at keys greater than or equal to <key-pattern>
. For strictly greater than, use --gt
.
# output all keys and values after 'foo' (implicit --all)
lev --gte 'foo'
# output all keys after 'foo'
lev --keys --gte 'foo'
# the same for values
lev --values --gte 'foo'
For keys and values strictly greater tha
--lte <key-pattern>
End the range at keys lower than or equal to <key-pattern>
. For strictly lower than, use --
.
# output all keys and values before 'fooz' (implicit --all)
lev --lte 'fooz'
# output all keys before 'fooz'
lev --keys --lte 'fooz'
# the same for values
lev --values --lte 'fooz'
# output all keys between 'foo' and 'fooz'
lev --keys --gte 'foo' --lte 'fooz'
# which is equivalent to
--prefix <key-pattern>
Get all entries for which the key starts by a given prefix
# get all the keys starting by foo
lev --keys --prefix 'foo'
# which is equivalent to
lev --keys --gte 'foo' --lte 'foo\uffff'
--match <key-pattern>
Filter results by a pattern applied on the keys
lev --keys --match 'f*'
lev --values --match 'f*'
lev --all --match 'f*'
# Equivalent to
lev --match 'f*'
See minimatch
doc for patterns
--limit <number>
Limit the number of records emitted in the current range.
lev --keys --limit 10
lev --values --prefix 'foo' --limit 100
lev --match 'f*' --limit 10
--reverse
Reverse the stream.
lev --keys --reverse
lev --keys --prefix 'foo' --limit 100 --reverse
--count
Output the count of results in the selected range
# Count all the key/value pairs in the database
lev --count
# Counts the keys and values between 'foo' and 'fooz'
lev --prefix 'foo' --count
--valueEncoding <string>
Specify the encoding for the values (Defaults to 'json').
lev --values --valueEncoding buffer
--location <string>
Specify the path to the LevelDB to use. Defaults to the current directory.
lev --location /tmp/test-db --keys
# Equivalent to
lev /tmp/test-db --keys
--map <JS function string or path>
Pass results in a map function
- either inline
lev --keys --map 'key => key.split(":")[1]'
lev --all --map 'data => data.value.replace(data.key, "")'
- or from a JS file that exports a function
# in ./map_fn.js
module.exports = key => key.split(":")[1]
lev --keys --map ./map_fn.js
If the function, returns null or undefined, the result is filtered-out
This can be used to update the whole database:
# Create a map function that returns an object with the key and an updated value
echo 'module.exports = ({ key, value }) => ({
key,
value: value.replace('foo', 'bar')
})' > ./update_values.js
# Create an updated export of the database
lev --map ./update_values.js > ./updated_db
# And re-import
lev --batch ./updated_db
REPL
Start the REPL
# in the current directory
$ lev .
# somewhere else
$ lev path/to/db
Use upper or lower case for the following commands.
GET <key>
Get a key from the database.
PUT <key> <value>
Put a value into the database. If you have keyEncoding
or valueEncoding
set to json
, these values will be parsed from strings into json
.
DEL <key>
Delete a key from the database.
LS
Get all the keys in the current range.
START <key-pattern>
Defines the start of the current range. You can also use GT
or GTE
.
END <key-pattern>
Defines the end of the current range. You can also use LT
or LTE
.
LIMIT <number>
Limit the number of records in the current range (defaults to 5000).
REVERSE
Reverse the records in the current range.