A small example application to showcase the basic features of the nacelle service framework.
This example application is organized as an HTTP and gRPC API (with equivalent functionality) that publish a message via Redis Pub/Sub to a worker process. This message contains a URL, and the worker performs an HTTP GET on the given URL. The response and/or error produced by this action is stored into a unique key in Redis, which can be fetched by a subsequent request to either API.
The application entrypoints (the HTTP API, the gRPC API, and the worker) are located in the cmd directory.
The main function for each API boots nacelle with a initializer that dials Redis and a server initializer for the process provided by this library. The connection created by the former is injected into the later.
The main function for the worker boots with an initializer for a Redis Pub/Sub client, which adds additional subscription/unsubscription logic to the Redis connection.
It is suggested that you build and run with Docker. Simply run docker-compose up. This will compile the three commands via multi-stage builds and start containers for the two APIs, a container for the worker, and a container for the Redis dependency.
The following shows an example of a successful request to the GitHub API user's list. The following output has been trimmed to pretty-print the first two results.
$ curl -i http://localhost:5000/ -X POST -d 'http://github.com/api/users'
HTTP/1.1 202 Accepted
Date: Fri, 21 Jun 2019 02:58:14 GMT
Content-Length: 45
Content-Type: text/plain; charset=utf-8
{"id":"b70d1b06-4f8d-4d07-bbd3-fa753bee7474"}$ curl -s http://localhost:5000/2166ac52-e1aa-423f-a573-3e881b881bd1 | jq -r '.body' | jq '.[:2]'
[
{
"login": "mojombo",
"id": 1,
"node_id": "MDQ6VXNlcjE=",
"avatar_url": "https://avatars0.githubusercontent.com/u/1?v=4",
"gravatar_id": "",
"url": "https://api.github.com/users/mojombo",
"html_url": "https://github.com/mojombo",
"followers_url": "https://api.github.com/users/mojombo/followers",
"following_url": "https://api.github.com/users/mojombo/following{/other_user}",
"gists_url": "https://api.github.com/users/mojombo/gists{/gist_id}",
"starred_url": "https://api.github.com/users/mojombo/starred{/owner}{/repo}",
"subscriptions_url": "https://api.github.com/users/mojombo/subscriptions",
"organizations_url": "https://api.github.com/users/mojombo/orgs",
"repos_url": "https://api.github.com/users/mojombo/repos",
"events_url": "https://api.github.com/users/mojombo/events{/privacy}",
"received_events_url": "https://api.github.com/users/mojombo/received_events",
"type": "User",
"site_admin": false
},
{
"login": "defunkt",
"id": 2,
"node_id": "MDQ6VXNlcjI=",
"avatar_url": "https://avatars0.githubusercontent.com/u/2?v=4",
"gravatar_id": "",
"url": "https://api.github.com/users/defunkt",
"html_url": "https://github.com/defunkt",
"followers_url": "https://api.github.com/users/defunkt/followers",
"following_url": "https://api.github.com/users/defunkt/following{/other_user}",
"gists_url": "https://api.github.com/users/defunkt/gists{/gist_id}",
"starred_url": "https://api.github.com/users/defunkt/starred{/owner}{/repo}",
"subscriptions_url": "https://api.github.com/users/defunkt/subscriptions",
"organizations_url": "https://api.github.com/users/defunkt/orgs",
"repos_url": "https://api.github.com/users/defunkt/repos",
"events_url": "https://api.github.com/users/defunkt/events{/privacy}",
"received_events_url": "https://api.github.com/users/defunkt/received_events",
"type": "User",
"site_admin": false
}
]The following shows an example of a failed request.
curl -i http://localhost:5000/ -X POST -d 'not even a url'
HTTP/1.1 202 Accepted
Date: Fri, 21 Jun 2019 03:04:22 GMT
Content-Length: 45
Content-Type: text/plain; charset=utf-8
{"id":"cde60fec-1ec5-4945-83fd-bcfd86040f44"}curl -s http://localhost:5000/47c99f6b-000b-4ac9-8d98-120186f105f6 | jq
{
"body": "",
"error": "Get not%20even%20a%20url: unsupported protocol scheme \"\""
}