Hulypulse

Hulypulse is a service that enables clients to share information on a “whiteboard”. Clients connected to the same “whiteboard” see data provided by other clients to the whiteboard.

The service is exposed as REST and WebSocket API.

Usage scenarios:

• user presence in a document
• user is “typing” event
• user cursor position in editor or drawing board
• service posts a process status

Key

Key is a string that consists of one or multiple segments separated by ‘/’. Example: foo/bar/baz. Key may not end with ‘/’ Segment may not contain special characters (‘*’, ‘?’, ‘[’, ‘]’,‘\’,‘\x00..\xF1’,‘\x7F’,‘"’,‘'’) Segment may not be empty Key segment may be private (prefixed with ‘$’)

Query

May not contain special characters (‘*’, ‘?’, ‘[’, ‘]’,‘\’,‘\x00..\xF1’,‘\x7F’,‘"’,‘'’) It is possible to use prefix, for listings / subscriptions (prefix ends with segment separator ‘/’)

• GET/SUBSCRIBE/.. a/b → single key

• GET/SUBSCRIBE/.. a/b/c/ → multiple

  If multiple

select all keys starting with prefix skip keys, containing private segments to the right from the prefix

example

• 1. /a/b/$c/$d, 2. /a/b/c, 3. /a/b/$c, 4. /a/b/$c/$d/e
• / → [2]
• /a/b/ → [2]
• /a/b/$c/ → [3]
• /a/b/$c/$d/ → [4]
• /a/b/$c/$d → [1]

Data

“Data” is an arbitrary JSON document. Size of data is limited to some reasonable size

HTTP API

GET /status - server status and websockets count

• Answer: {"status":"OK","websockets":2}

PUT /{workspace}/{key} - Save key

• Input
  • Body - data
  • Content-Type: application/json
  • Content-Length: optional
  • Headers: TTL or absolute expiration time
  • HULY-TTL — autodelete in N seconds
  • or HULY-EXPIRE-AT — autodelete in UnixTime
  • default max_ttl = 3600 (settings in config/default.toml)
  • Conditional Headers:
  • If-Match: * — update only if the key exists
  • If-Match: <md5> — update only if current value's MD5 matches
  • If-None-Match: * — insert only if the key does not exist
• Output
  • Status:
  • 201 if inserted with If-None-Match: *
  • 204 on successful insert or update
  • 412 if the condition is not met
  • 400 if headers are invalid
  • Body: DONE

DELETE /{workspace}/{key} - Delete key

• Output
  • Status: 204 No content, no body
  • 404 Not Found if nothing to do

GET /{workspace}/{key} - Read one key

• Output
  • Status 200
  • Content-type: application/json
  • Header: Etag: <md5>
  • Body:
    • workspace (copy of input)
  • key (copy of input)
    • data (copy of input)
    • expiresAt / TTL (copy of input, optional)
  • etag

GET /{workspace}/{key}/ - Read array of keys

• Output
  • Status 200
  • Content-type: application/json
  • Body (array):
  • [{"key","data","expires_at","etag"}, ...]

WebSocket API

Client to Server

PUT - type: "put" - correlation id (optional) - key: - “workspace/foo/bar“ - shared key - “workspace/foo/bar/$/secret“ - secret key - data ** time control (optional) ** - TTL — autodelete in N seconds - ExpireAt — autodelete in UnixTime - or default max_ttl = 3600 (settings in config/default.toml) ** Conditional (optional) ** - ifMatch: * — update only if the key exists - ifMatch: <md5> — update only if current value's MD5 matches - ifNoneMatch: * — insert only if the key does not exist

• Answer: {"action":"put","correlation":"abc123","result":"OK"}

GET - type: "get" - correlation id (optional) - key: - “workspace/foo/bar“ - one shared key - “workspace/foo/bar/$/secret“ - one secret key

• Answer: {"action":"get","result":{"data":"hello","etag":"5d41402abc4b2a76b9719d911017c592","expires_at":3599,"key":"00000000-0000-0000-0000-000000000001/foo/bar"}}

LIST - type: "list" - correlation id (optional) - key: - “workspace/foo/bar/“ - keys from public space - “workspace/foo/bar/$/secret/“ - keys from secret space

• Answer: {"action":"list","result":[{"data":"hello 1","etag":"df0649bc4f1be901c85b6183091c1d83","expires_at":3570,"key":"00000000-0000-0000-0000-000000000001/foo/bar1"},{"data":"hello 2","etag":"bb21ec8394b75795622f61613a777a8b","expires_at":3555,"key":"00000000-0000-0000-0000-000000000001/foo/bar2"}]}

DELETE - type: "delete" - correlation id (optional) - key: “workspace/foo/bar“ ** Conditional (optional) ** - ifMatch: <md5> — delete only if current value's MD5 matches - ifMatch: * — return error if key does not exist

• Answer: {"action":"delete","result":"OK"}

SUBSCRIBE type: "sub" key: - “workspace/foo/bar“ - subscribe one shared key - “workspace/foo/bar/“ - subscribe all keys started with - “workspace/foo/bar/$/my_secret“ - subscribe one secret key - “workspace/foo/bar/$/my_secret/“ - subscribe all keys started with secret

• Answer: {"action":"sub","result":"OK"}

UNSUBSCRIBE - type: "unsub" - key: - “workspace/foo/bar“ - unsubscribe subscribed key - “*“ - unsubscribe all

• Answer: {"action":"unsub","result":"OK"}

MY SUBSCRIBES - type: "sublist"

• Answer: {"action":"list","result":["00000000-0000-0000-0000-000000000001/foo/bar1","00000000-0000-0000-0000-000000000001/foo/bar2"]}

INFO - type: "info"

• Answer: {"db_mode":"memory","memory_info":"1231 keys, 80345 bytes","status":"OK","websockets":164}

** Server to Client ** subscribed events:

- `{"message":"Set","key":"00000000-0000-0000-0000-000000000001/foo/bar","value":"hello"}`

- `{"message":"Expired","key":"00000000-0000-0000-0000-000000000001/foo/bar"}`

- `{"message":"Del","key":"00000000-0000-0000-0000-000000000001/foo/bar"}`

Special options in config/default.toml

- ```memory_mode = true``` Use native memory storage instead Redis
- ```no_authorization = true``` Don't check authorization
- ```max_size = 100``` Max value size in bytes

Running

Pre-build docker images is available at: hardcoreeng/service_hulypulse:{tag}.

You can use the following command to run the image locally:

docker run -p 8095:8095 -it --rm hardcoreeng/service_hulypulse:{tag}"

If you want to run the service as a part of local huly development environment use the following command:

 export HULY_REDIS_URLS="redis://huly.local:6379"
 docker run --rm -it --network dev_default -p 8095:8095 hardcoreeng/service_hulypulse:{tag}

This will run Hulypulse in the same network as the rest of huly services, and set the redis connection string to the one matching the local dev redis instance.

You can then access hulypulse at http://localhost:8095.

Authetication

Hulypulse uses bearer JWT token authetication. At the moment, it will accept any token signed by the hulypulse secret. The secret is set in the environment variable HULY_TOKEN_SECRET variable.

Configuration

The following environment variables are used to configure hulypulse:

• HULY_BIND_HOST: host to bind the server to (default: 0.0.0.0)
• HULY_BIND_PORT: port to bind the server to (default: 8094)
• HULY_TOKEN_SECRET: secret used to sign JWT tokens (default: secret)
• HULY_REDIS_URLS: redis connection string (default: redis://huly.local:6379)
• HULY_REDIS_PASSWORD: redis password (default: "<invalid>")
• HULY_REDIS_MODE: redis mode "direct" or "sentinel" (default: "direct")
• HULY_REDIS_SERVICE: redis service (default: "mymaster")
• HULY_MAX_TTL: maximum storage time (default: 3600)
• TODO: HULY_PAYLOAD_SIZE_LIMIT: maximum size of the payload (default: 2Mb)

Todo (in no particular order)

• Optional value encryption
• Support for open telemetry
• Concurrency control for database migration (several instances of hulypulse are updated at the same time)
• TLS support
• Liveness/readiness probe endpoint

Contributing

Contributions are welcome! Please open an issue or a pull request if you have any suggestions or improvements.

License

This project is licensed under EPL-2.0