Add an example of a simple storage server

[johningve]

This PR adds an example storage server with a nice CLI to play with RPCs, quorum calls and configurations.

Currently depends on #81

[meling]

We don’t want to refer to GOPATH. Suggest we just remove this, unless we actually depend on paths; if we do we could explain that we use GOBIN as a reference for where our go binaries are saved.

[johningve]

I think it's still relevant to use GOPATH here though. That way you can simply run go get github.com/relab/gorums/examples/storage. And then the storage binary will be available. I've always thought of GOPATH/bin as the "default", and GOBIN as an override.

[meling]

ok. Maybe we can just link to the official instructions, to avoid being specific about GOPATH. They also use this:

$ go get golang.org/x/tour
This will place the tour binary in your workspace's bin directory.

[johningve]

Looks like they mean GOPATH when they say "workspace"
https://web.archive.org/web/20190806061015/https://golang.org/doc/code.html#Workspaces

[johningve]

"the GOPATH environment variable specifies the location of your workspace"

[johningve]

@meling I found two alternatives for implementing a readline-style CLI:

1. github.com/chzyer/readline
2. golang.org/x/crypto/ssh/terminal

The first one has a much larger feature set, but the project seems to be abandoned. It is still, however, used by google/pprof. It also has some minor issues on windows

The second one has the basic features we need, but struggles with arrow keys on windows for some reason. This package is used by the pprof tool shipped by Go. Additionally, it looks like this package is moving to golang.org/x/term in the future.

We could also try using the github.com/containerd/console package as suggested on stackoverflow

For now option 2 is implemented, and it works on windows except for arrow keys.

[meling]

@meling I found two alternatives for implementing a readline-style CLI:

1. github.com/chzyer/readline
2. golang.org/x/crypto/ssh/terminal

The first one has a much larger feature set, but the project seems to be abandoned. It is still, however, used by google/pprof. It also has some minor issues on windows

The second one has the basic features we need, but struggles with arrow keys on windows for some reason. This package is used by the pprof tool shipped by Go. Additionally, it looks like this package is moving to golang.org/x/term in the future.

We could also try using the github.com/containerd/console package as suggested on stackoverflow

For now option 2 is implemented, and it works on windows except for arrow keys.

I don't have a strong preference, but it seems like going with the x/term version (to be) is a good option.

[johningve]

Also, how do you feel about using a separate go.mod for the examples? VSCode still has a problem with it, but it can be worked around by creating a multi-root workspace.

The reason I wanted to have a separate module for the examples, was to try to make them separate from the gorums module, and preventing them from showing up in godoc, etc.

[meling]

I actually prefer to use multiple modules for these things. But there are problems with VSCode; I find that with multi-root workspaces if you (accidentally) navigate into another module (from the top-level workspace) I get errors in files... Hopefully VSCode gets better at handling multi-root workspaces.