https://github.com/hackergrrl/append-only-log

:train: :train: :train: Test suite & interface for append-only log modules.
https://github.com/hackergrrl/append-only-log

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:train: :train: :train: Test suite & interface for append-only log modules.

• Host: GitHub
• URL: https://github.com/hackergrrl/append-only-log
• Owner: hackergrrl
• Created: 2016-06-18T07:55:55.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2016-06-18T08:01:56.000Z (over 8 years ago)
• Last Synced: 2024-09-29T09:22:33.923Z (4 days ago)
• Language: JavaScript
• Homepage:
• Size: 3.91 KB
• Stars: 3
• Watchers: 2
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

        
# append-only-log

> Abstract interface for an append-only log.

Like [abstract-blob-store](https://github.com/maxogden/abstract-blob-store), but

for append-only logs.

## STATUS

Mad science work-in-progress! :dragon_face:

## Usage

To use the test suite from this module, use `require('append-only-log/tests')`.

You'll have to implement a setup and teardown function:

```js

var common = {

  setup: function(t, cb) {

    // setup takes a tap/tape compatible test instance in and a callback

    // this method should construct a new blob store instance and pass it to the callback:

    var log = createMyLog()

    cb(null, log)

  },

  teardown: function(t, log, blob, cb) {

    // teardown takes in the test instance, as well as the log instance

    // you can use the log to clean up its data, e.g.

    if (log) {

      var stream = log.createReadStream()

      stream.on('data', function (entry) {

        entry.cleanup()

      })

      stream.on('end', cb)

    } else cb()

    // be sure to call cb() when you are done with teardown

  }

}

```

To run the tests simply pass your test module (tap or tape or any other

compatible modules are supported) and your common methods in:

```js

var appendOnlyLogTests = require('append-only-log/tests')

appendOnlyLogTests(test, common)

```

## API

A valid append-only log should implement the following APIs. There is a

reference in-memory implementation available at `index.js` in this repo.

### log.append(value, cb)

Appends `value` to the end of the log. If a function `cb` is given, it will be

called asynchronously as `function (err, seq)`. `seq` is the sequence number of

the appended entry.

### log.get(seq, cb)

Gets the value with sequence number `seq` from the log asynchronously. `cb` has

the signature `function (err, value)`.

### log.createReadStream(opts)

Returns a Readable stream of values in the append-only log, starting from the

most recently appended. Some implementations may accept `opts.reverse` for

reversed entries, but this is not guaranteed.

## Install

With [npm](https://npmjs.org/) installed, run

```

$ npm install append-only-log

```

## Acknowledgments

`append-only-log` was inspired by

[abstract-blob-store](https://github.com/maxogden/abstract-blob-store).

## See Also

- [`noffle/common-readme`](https://github.com/noffle/common-readme)

## License

ISC