[training#1] add catalog ls task into node discovery graph

[iceiilin]

Background

Training#1: Design a Linux catalog task which parse the ls -l /var and store the result into source ls.

Related PR:

iceiilin/on-taskgraph#2

Implementation:

add task definition and command parser for catalog ls task

Result:

After node discovery, a "ls" catalog source is shown as below:

onrack@lyne-env:~$ http :8080/api/2.0/nodes/59acfc42fb8955313565944b/catalogs/ls
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Connection: keep-alive
Content-Length: 2256
Content-Type: application/json; charset=utf-8
Date: Mon, 04 Sep 2017 07:14:58 GMT
ETag: W/"8d0-o2+9cR5kqs5430MBQB2PN97lCdY"
X-Powered-By: Express

{
    "createdAt": "2017-09-04T07:12:20.813Z",
    "data": [
        {
            "file_type": "directory",
            "group": "root",
            "link_count": "2",
            "modifiedtime": "Apr 10 2014",
            "name": "backups",
            "owner": "root",
            "permission": {
                "group": "r-x",
                "others": "r-x",
                "user": "rwx"
            },
            "size": "3"
        },
        {
            "file_type": "directory",
            "group": "root",
            "link_count": "1",
            "modifiedtime": "Sep 4 07:11",
            "name": "cache",
            "owner": "root",
            "permission": {
                "group": "r-x",
                "others": "r-x",
                "user": "rwx"
            },
            "size": "100"
        },
...
        {
            "file_type": "directory",
            "group": "root",
            "link_count": "2",
            "modifiedtime": "Jun 21 00:23",
            "name": "tmp",
            "owner": "root",
            "permission": {
                "group": "rwx",
                "others": "rwt",
                "user": "rwx"
            },
            "size": "3"
        }
    ],
    "id": "734f37ac-34bc-4b77-9d1e-35df396944a1",
    "node": "59acfc42fb8955313565944b",
    "source": "ls",
    "updatedAt": "2017-09-04T07:12:20.813Z"
}