Connection write mode option

[fabscav]

This PR adds a new option to connections: write mode, It can have one of three values:

• Enabled (default): Current behavior, full write access.
• Confirm: All queries that change data or structure have to be confirmed.
• Read-only: Queries that change data or structure are not allowed.

[rathboma]

My concern is that there could be select statements containing some of these words legitimately. We already have a dependency on sql-query-identifier, we should probably rely on that.

I think I'd also be uncomfortable (right now) saying that beekeeper can prevent write operations, I think warning is fine, but sql-query-identifier would probably need some new features.

read-only mode should probably be implemented database-by-database, for example in postgres - brianc/node-postgres#569

To do that we'd need to run a statement before each query is executed.

[fabscav]

I updated the component to utilize the sql-query-identifier instead of the verb array. However I did notice it doesn't mark alter table queries as modifications.

Implementing write-protection on a connection-level should be possible. SQLite and SQL Server support this as a connection param afaik. Others such as MySQL would probably require the query to be wrapped in a read only transaction.

I could look into implementing it, but if you're reluctant with implementing a read-only mode in general I'd be fine with dropping this PR as well. Tbh I only need this functionality to be present in my fork in order to start using beekeeper in production environments.

[rathboma]

I'm 100% open to this feature. I think it would be a great feature.

Yes, if we can do read-only mode at the connection-level that would be fantastic, although I know that's a lot of work.

We could use the following:

• user selects read-only
• if connection support it, works as expected
• If not, we provide a warning that it might not be 100%, and implement at the app level

For 'warn me' mode:

• provide a warning on the connection screen that the feature is in beta and might not be 100%.

If we do those things, I'm good with it.

With alter table -- ideally we can add basic detection to sql-query-identifier

[rathboma]

Hey! I think this is a good draft, but it's been a while since you've been working on it. I think it best I close it for now, eventually we'll come back to this as part of a real permissions system.