Add a remote/server/cluster feature

[neilotoole]

You should be able to have the sq query execute remotely on a server/cluster. For example:

> sq remote create aws myaws1 ...
Created cluster and added remote "myaws1"
> sq --remote=myaws1 '@mysql1.tbluser, @pg1.tbladdress | join(.uid)'
# Add a pre-existing cluster, e.g. one set up by an admin
> sq remote add myazure1 http://my_sq_lb.azure.com --username=ETC
> sq --remote=myazure1 '@mysql1.tbluser, @pg1.tbladdress | join(.uid)'

There's two pieces here: the first is creating (or adding) the remote cluster, the second is executing the query remotely.

The service consists of a load balancer that directs requests to a bunch of sq server instances (just web servers wrapping libsq deployed in Docker containers). The sq --remote=myaws1 QUERY command posts the query and the local config to the server. If the query refers to a local data source, the server will send a response with upload URLs for the local files (e.g. http://myaws1.aws.amazon.com/upload/GUID). sq will upload those files, and the server will run the query, occasionally sending status updates to the client, while the client waits for the job to complete.

[neilotoole]

Out of scope.