werehamster / google-cloud Goto Github PK

The library is incomplete. I only implemented the functions which I need in my own projects. But the basic infrastructure is there so that adding new API endpoints is relatively easy.

To interact with the Google Cloud API you need an access token. The easiest way to obtain one is through the metadata service. That only works on instances which run in the Google Cloud and have a service account attached to them.

All actions which interact with the Google Cloud API run in the Cloud monad. The monad wraps IO, Except and Reader. You get convenience functions to send out HTTP requests and parse responses. The monad also acts as a cache for some frequently used values (such as the access token). All synchronous exceptions are caught and transformed into an Error.

To run a Cloud action you need a Handle. Because it is relatively expensive to create a handle, you should create one for your whole application. You can either use a convenience function which creates a new Handle with sensible defaults (createHandle), or you can use one which gives you more options to customize the handle (mkHandle).

This code uploads a ByteString into a Google Cloud Storage bucket.

{-# LANGUAGE OverloadedStrings #-}

import Google.Cloud         (newHandle, evalCloud)
import Google.Cloud.Storage (Bucket(..), Name(..), uploadMedia)

main :: IO ()
main = do
    let bucket = Bucket "test-bucket-123"
        name   = Name "file/name.txt"

    h <- createHandle
    evalCloud h $ do
        uploadMedia bucket name "file body" "application/octet-stream"