Luntic

A lightweight REST in-memory discovery service.

Features:

periodical task for removing expired records;
simple dashboard in web browser.

The service was inspired by Eureka web service and it uses for registration and locating services in your environment.

It uses REST JSON-based API for simple integration.

Getting Started

Start the Luntic discovery server:

$> luntic

    __                  __   _
   / /   __  __ ____   / /_ (_)_____
  / /   / / / // __ \ / __// // ___/
 / /___/ /_/ // / / // /_ / // /__
/_____/\__,_//_/ /_/ \__//_/ \___/

I was born!

v1.1.0
Copyright (c) by Artem Labazin

REST requests are serviced on: http://0.0.0.0:8080/

If you need to launch Luntic on different port, with specific path prefix, debug access logs or public net address, you are able to set it:

$> luntic --debug --port=9999 --path-prefix=/register localhost

    __                  __   _
   / /   __  __ ____   / /_ (_)_____
  / /   / / / // __ \ / __// // ___/
 / /___/ /_/ // / / // /_ / // /__
/_____/\__,_//_/ /_/ \__//_/ \___/

I was born!

v1.1.0
Copyright (c) by Artem Labazin

REST requests are serviced on: http://localhost:9999/register

2017-07-22T03:20:45+03:00 -- POST   /register/popa
2017-07-22T03:21:12+03:00 -- GET    /register
2017-07-22T03:21:28+03:00 -- DELETE /register/popa/59729a5d8b7df47200000001

We could also start a simple web browser dashboard on separate port:

$> luntic --dashboard:9876

    __                  __   _
   / /   __  __ ____   / /_ (_)_____
  / /   / / / // __ \ / __// // ___/
 / /___/ /_/ // / / // /_ / // /__
/_____/\__,_//_/ /_/ \__//_/ \___/

I was born!

v1.1.0
Copyright (c) by Artem Labazin

REST requests are serviced on: http://0.0.0.0:8080/
Dashboard is available on: http://0.0.0.0:9876/

Open the link http://localhost:9876 in your web browser and you could see something like this:

And see group info:

Also there is a API page:

To see all available switches and keys, type the following:

$> luntic --help

Usage:  luntic [OPTIONS] [LISTENING_ADDRESS]

A lightweight REST in-memory discovery service

Options:
    -p:PORT --port=PORT   sets listening port
                          default: 8080
    --path-prefix=PATH    sets server's endpoints path prefix
                          default: '/'
    --heartbeat=SECONDS   sets heartbeat service cleaner in seconds,
                          if it set to 0 - turn off heartbeat scheduler
                          default: 0s
    --dashboard=PORT      setups a simple web browser-oriented dashboard
                          for services monitoring
                          default: turned off
    -d --debug            turn on debug mode
    -v --version          prints program's version
    -h --help             prints this help menu

After starting Luntic server you could register your first app via REST API. I am using HTTPie for request calls, but you can do it with cURL or Postman.

Registering a new app, which has popa group name:

$> http -v POST :8080/popa
POST /popa HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 0
Host: localhost:8080
User-Agent: HTTPie/0.9.9


HTTP/1.1 201 Created
Content-Length: 124
content-type: application/json
location: /popa/597298af0937867200000001
x-expired-time: 0

{
    "created": "2017-07-22T03:13:35+03:00",
    "group": "popa",
    "id": "597298af0937867200000001",
    "modified": "2017-07-22T03:13:35+03:00"
}

As we can see, we have created a new record in popa application group. The server have generated the instance id 597298af0937867200000001, creation time and last modified time fields.

We are also able to attach our own JSON object to a record in meta field during its creation:

$> http -v POST :8080/popa one=1 two=2
POST /popa HTTP/1.1
Accept: application/json, */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 24
Content-Type: application/json
Host: localhost:8080
User-Agent: HTTPie/0.9.9

{
    "one": "1",
    "two": "2"
}

HTTP/1.1 201 Created
Content-Length: 154
content-type: application/json
location: /popa/5972a20d5b31ed7400000001
x-expired-time: 0

{
    "created": "2017-07-22T03:53:33+03:00",
    "group": "popa",
    "id": "5972a20d5b31ed7400000001",
    "meta": {
        "one": "1",
        "two": "2"
    },
    "modified": "2017-07-22T03:53:33+03:00"
}

To get a just created record - we need to use a path from Location header in creation reponse:

$> http -v :8080/popa/5972a2e54396247500000001
GET /popa/5972a2e54396247500000001 HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Host: localhost:8080
User-Agent: HTTPie/0.9.9


HTTP/1.1 200 OK
Content-Length: 154
content-type: application/json

{
    "created": "2017-07-22T03:53:33+03:00",
    "group": "popa",
    "id": "5972a20d5b31ed7400000001",
    "meta": {
        "one": "1",
        "two": "2"
    },
    "modified": "2017-07-22T03:53:33+03:00"
}

Also, we could get all available records within one group name:

$> http -v :8080/popa
GET /popa HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Host: localhost:8080
User-Agent: HTTPie/0.9.9


HTTP/1.1 200 OK
Content-Length: 282
content-type: application/json

[
    {
        "created": "2017-07-22T03:13:35+03:00",
        "group": "popa",
        "id": "597298af0937867200000001",
        "modified": "2017-07-22T03:13:35+03:00"
    },
    {
        "created": "2017-07-22T03:53:33+03:00",
        "group": "popa",
        "id": "5972a20d5b31ed7400000001",
        "meta": {
            "one": "1",
            "two": "2"
        },
        "modified": "2017-07-22T03:53:33+03:00"
    }
]

Or, we can get all data in one object - group -> instances:

$> http -v :8080/
GET / HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Host: localhost:8080
User-Agent: HTTPie/0.9.9


HTTP/1.1 200 OK
Content-Length: 426
content-type: application/json

{
    "popa": [
        {
            "created": "2017-07-22T03:13:35+03:00",
            "group": "popa",
            "id": "597298af0937867200000001",
            "modified": "2017-07-22T03:13:35+03:00"
        },
        {
            "created": "2017-07-22T03:53:33+03:00",
            "group": "popa",
            "id": "5972a20d5b31ed7400000001",
            "meta": {
                "one": "1",
                "two": "2"
            },
            "modified": "2017-07-22T03:53:33+03:00"
        }
    ],
    "zuul": [
        {
            "created": "2017-07-22T04:03:26+03:00",
            "group": "zuul",
            "id": "5972a45e4396247500000003",
            "modified": "2017-07-22T04:03:26+03:00"
        }
    ]
}

To update last modified time you could type this:

$> http -v PUT :8080/popa/5972a20d5b31ed7400000001
PUT /popa/5972a20d5b31ed7400000001 HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 0
Host: localhost:8080
User-Agent: HTTPie/0.9.9


HTTP/1.1 200 OK
Content-Length: 154
content-type: application/json

{
    "created": "2017-07-22T03:53:33+03:00",
    "group": "popa",
    "id": "5972a20d5b31ed7400000001",
    "meta": {
        "one": "1",
        "two": "2"
    },
    "modified": "2017-07-22T04:10:42+03:00"
}

Why do we want to update last modified time? Luntic can be started with --heartbeat=SECONDS switch, which enables scheduled task for periodical removing expired instances in groups. So, with this switch you need to update modified time, otherwise it removes. By default this scheduled task is disabled.

With PUT method you could also change meta field:

$> http -v PUT :8080/popa/5972a20d5b31ed7400000001 greeting="Hello world" one=1 two=2
PUT /popa/5972a20d5b31ed7400000001 HTTP/1.1
Accept: application/json, */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 51
Content-Type: application/json
Host: localhost:8080
User-Agent: HTTPie/0.9.9

{
    "greeting": "Hello world",
    "one": "1",
    "two": "2"
}

HTTP/1.1 200 OK
Content-Length: 179
content-type: application/json

{
    "created": "2017-07-22T03:53:33+03:00",
    "group": "popa",
    "id": "5972a20d5b31ed7400000001",
    "meta": {
        "greeting": "Hello world",
        "one": "1",
        "two": "2"
    },
    "modified": "2017-07-22T04:12:16+03:00"
}

And at last, we want to remove the record:

$> http -v DELETE :8080/popa/5972a20d5b31ed7400000001
DELETE /popa/5972a20d5b31ed7400000001 HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 0
Host: localhost:8080
User-Agent: HTTPie/0.9.9


HTTP/1.1 204 No Content
Content-Length: 0

Docker

You also are able to use already prepared Docker image:

$> docker run \
    -p 8080:8080 -p 9876:9876 \
    xxlabaza/luntic:1.1.0 \
    --debug --dashboard:9876

API

Registering new service

Creates new record.

Request

POST [/pathPrefix]/{group}

pathPrefix - common path prefix, which was set (default value - /) at the start of Luntic program;

group - name of the registering application group.

Examples:
- POST /popa - we didn't set pathPrefix (it is optional) at start time and set group in this request as popa;
- POST /api/popa - we set pathPrefix at start time and use it in the request (api), also we set group (popa).
Also, you could send a JSON object with a request. It will be attached to server generated instance in meta field.

Success Response:

As a result of the request we get a response:

Code: 201

Headers:

Location: [/pathPrefix]/{group}/{instanceId}
X-Expired-Time: <int_seconds_or_zero_if_disabled>

Content type: application/json

JSON fields:

Field name	Optional	Description
id	no	generated record id
group	no	the group name you set
created	no	the time you registered
modified	no	the time you last accessed the record
meta	yes	if you send `JSON` in request, we get it back in that field

IMPORTANT: Take a look at X-Expired-Time header - if it is not 0 value, your record expires after that amount of second. To prevent removing your instance record - make a PUT request within this timeout.

Error Response:

400 - in case of incorrect group set (absent or contains / sign)

Examples:

$> http -v POST :8080/popa

POST /popa HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 0
Host: localhost:8080


HTTP/1.1 201 Created
Content-Length: 124
Content-Type: application/json
Location: /popa/597298af0937867200000001

{
    "created": "2017-07-22T03:13:35+03:00",
    "group": "popa",
    "id": "597298af0937867200000001",
    "modified": "2017-07-22T03:13:35+03:00"
}

$> http -v POST :8080/popa one=1 two=2

POST /popa HTTP/1.1
Accept: application/json, */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 24
Content-Type: application/json
Host: localhost:8080

{
    "one": "1",
    "two": "2"
}


HTTP/1.1 201 Created
Content-Length: 154
Content-Type: application/json
Location: /popa/5972a20d5b31ed7400000001

{
    "created": "2017-07-22T03:53:33+03:00",
    "group": "popa",
    "id": "5972a20d5b31ed7400000001",
    "meta": {
        "one": "1",
        "two": "2"
    },
    "modified": "2017-07-22T03:53:33+03:00"
}

Retrieve services

Returns all or specific records on the server.

Request

Get all groups and records:

GET [/pathPrefix]/

Get all group's records:

GET [/pathPrefix]/{group}

Get only specific record:

GET [/pathPrefix]/{group}/{instanceId}

pathPrefix - common path prefix, which was set (default value - /) at the start of Luntic program;

group - name of the registered application group.

instanceId - service instance id.

Success Response:

As a result of the request we get a response:

Code: 200

Content type: application/json

Content fields:

Field name	Optional	Description
id	no	generated record id
group	no	the group name you set
created	no	the time you registered time
modified	no	the time you last accessed the record
meta	yes	if you send `JSON` in request, we get it back in that field

Error Response:

404 - in case of nonexistent group or instanceId.

Examples:

Get all records in the services:

$> http -v :8080/
/ HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Host: localhost:8080
User-Agent: HTTPie/0.9.9


HTTP/1.1 200 OK
Content-Length: 397
content-type: application/json

{
    "popa": [
        {
            "created": "2017-07-23T03:41:51+03:00",
            "group": "popa",
            "id": "5973f0cfead3c64a00000001",
            "modified": "2017-07-23T03:41:51+03:00"
        },
        {
            "created": "2017-07-23T03:41:52+03:00",
            "group": "popa",
            "id": "5973f0d0ead3c64a00000002",
            "modified": "2017-07-23T03:41:52+03:00"
        }
    ],
    "zuul": [
        {
            "created": "2017-07-23T03:41:57+03:00",
            "group": "zuul",
            "id": "5973f0d5ead3c64a00000003",
            "modified": "2017-07-23T03:41:57+03:00"
        }
    ]
}

Get all records by group name:

$> http -v :8080/popa
GET /popa HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Host: localhost:8080
User-Agent: HTTPie/0.9.9


HTTP/1.1 200 OK
Content-Length: 253
content-type: application/json

[
    {
        "created": "2017-07-23T03:41:51+03:00",
        "group": "popa",
        "id": "5973f0cfead3c64a00000001",
        "modified": "2017-07-23T03:41:51+03:00"
    },
    {
        "created": "2017-07-23T03:41:52+03:00",
        "group": "popa",
        "id": "5973f0d0ead3c64a00000002",
        "modified": "2017-07-23T03:41:52+03:00"
    }
]

Get record by its group and instanceId:

$> http -v :8080/popa/5973f0cfead3c64a00000001
GET /popa/5973f0cfead3c64a00000001 HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Host: localhost:8080
User-Agent: HTTPie/0.9.9


HTTP/1.1 200 OK
Content-Length: 125
content-type: application/json

{
    "created": "2017-07-23T03:41:51+03:00",
    "group": "popa",
    "id": "5973f0cfead3c64a00000001",
    "modified": "2017-07-23T03:41:51+03:00"
}

Update service

This request, first of all, updates modified time field of the updating record.

Request

PUT [/pathPrefix]/{group}/{instanceId}

pathPrefix - common path prefix, which was set (default value - /) at the start of Luntic program;

group - name of the registered application group.

instanceId - service instance id for updating.

Also, you could send a JSON object with a request. It will be attached to server generated instance in meta field.

Success Response:

As a result of the request we get a response:

Code: 200

Content type: JSON

Content fields:

Field name	Optional	Description
id	no	generated record id
group	no	the group name you set
created	no	the time you registered time
modified	no	the time you last accessed the record
meta	yes	if you send `JSON` in request, we get it back in that field

Error Response:

400 - if not group or instanceId are present;

404 - in case of nonexistent group or instanceId.

Examples:

Regular modified time update:

http -v PUT :8080/popa/5973f0cfead3c64a00000001
PUT /popa/5973f0cfead3c64a00000001 HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 0
Host: localhost:8080
User-Agent: HTTPie/0.9.9


HTTP/1.1 200 OK
Content-Length: 125
content-type: application/json

{
    "created": "2017-07-23T03:41:51+03:00",
    "group": "popa",
    "id": "5973f0cfead3c64a00000001",
    "modified": "2017-07-23T03:46:22+03:00"
}

Update with attaching new meta field value:

http -v PUT :8080/popa/5973f0cfead3c64a00000001 name=Artem
PUT /popa/5973f0cfead3c64a00000001 HTTP/1.1
Accept: application/json, */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 17
Content-Type: application/json
Host: localhost:8080
User-Agent: HTTPie/0.9.9

{
    "name": "Artem"
}

HTTP/1.1 200 OK
Content-Length: 149
content-type: application/json

{
    "created": "2017-07-23T03:41:51+03:00",
    "group": "popa",
    "id": "5973f0cfead3c64a00000001",
    "meta": {
        "name": "Artem"
    },
    "modified": "2017-07-23T03:47:28+03:00"
}

Remove service

Deletes the service from the services.

Request

DELETE [/pathPrefix]/{group}/{instanceId}

pathPrefix - common path prefix, which was set (default value - /) at the start of Luntic program;

group - name of the registered application group.

instanceId - service instance id for removing.
Success Response:

As a result of the request we get a response:

Code: 204

No Content
Error Response:

400 - if not group or instanceId are present;

404 - in case of nonexistent group or instanceId.

Examples:

$> http -v DELETE :8080/popa/5972a20d5b31ed7400000001
DELETE /app/popa/5973e2c95d89804600000007 HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 0
Host: localhost:8080


HTTP/1.1 204 No Content
Content-Length: 0

Development

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.

Prerequisites

For building the project you need only a Nim compiler (Windows or OSX/Unix).

IMPORTANT: Luntic requires Nim version 0.17.0

And, of course, you need to clone Luntic from GitHub:

$> git clone https://github.com/xxlabaza/luntic
$> cd luntic

Building

For building routine automation, I am using config.nims file. It contains all needed tasks described in Nim language.

To build the Luntic project, do the following:

$> nim build
...
Hint: operation successful (52249 lines compiled; 4.124 sec total; 106.934MiB peakmem; Debug Build) [SuccessX]

If you need to build a release (less output binnary file size):

$> nim build release

To check, what everything is fine, type the nex command:

$> build/target/luntic -v
v1.1.0

To build a docker image:

$> nim docker

Running the tests

To run the project's test, do the following:

$> nim test
...
[OK] Parsing request parts

Also, if you build a release, the tests launch automatically.

Built With

Nim - is a systems and applications programming language

Changelog

To see what has changed in recent versions of Luntic, see the changelog file.

Contributing

Please read contributing file for details on my code of conduct, and the process for submitting pull requests to me.

Versioning

We use SemVer for versioning. For the versions available, see the tags on this repository.

Authors

Artem Labazin - the main creator and developer

License

This project is licensed under the Apache License 2.0 License - see the license file for details

Name		Name	Last commit message	Last commit date
Latest commit History 5 Commits
images		images
src		src
.gitignore		.gitignore
CHANGELOG.md		CHANGELOG.md
CONTRIBUTING.md		CONTRIBUTING.md
Dockerfile		Dockerfile
LICENSE		LICENSE
README.md		README.md
config.nims		config.nims

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Luntic

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Getting Started

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Registering new service

Retrieve services

Update service

Remove service

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Luntic

Contents

Getting Started

Docker

API

Registering new service

Retrieve services

Update service

Remove service

Development

Prerequisites

Building

Running the tests

Built With

Changelog

Contributing

Versioning

Authors

License

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