Is there a way to hook into an "afterMigrate" event?

[mpalmerlee]

I'm trying to figure out a way to always run code after a migration happens, in my case I'm using mysql and I'd like to ensure a set of views is up to date so that we don't have to manually re-create our views after the underlying schema of the table changes.
I noticed there is an endMigration event in the driver, maybe there is a way to hook into this?

Or perhaps if I put an index.js file in the migrations directory I can monkey patch the up function to call my recreate views methods after migrations are done?

Thanks for your help.

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[wzrdtales]

So you want to execute something after every migration? Or after all mgrations have been done?

endMigration is actually intended for transactions, currently there is no such hook though. Could you please specify what your use case is, so that I can better understand what exactly you need?

Thank you

[mpalmerlee]

No problem, here is what I'm trying to do:
I have some views in MySql, one unfortunate thing about MySql views is if you create them as SELECT * FROM tbl_name; it will expand the select to give you all of the columns at create time. The problem is, that if we then want to add or remove a column from the underlying table through a migration, the view needs to be re-created so that it sees the new or removed column.

We could manually do this in all migrations that change the underlying table, however then we have to remember to do this every time we change a table referenced by a view. I was hoping we could simple re-create all of our views anytime a migration is run. We could do this ourselves anytime we run db-migrate, but I was hoping there might be a built-in way to hook into the library.

[wzrdtales]

hum, okay. While I think that putting this after every migration would be really heavy and would really slow down your migrations I don't heave a big problem with that, I would just not suggest to do it. To say I'm not a big fan of: Doing something always to not be able to forget to do it, b/c this most often also means: I don't heave an idea what actually is happening. And as soon as you add more stuff to those hooks, everything gets worse. I would prefer control and clean migrations over your approach, but finally this is your decision ;)

So generally I don't have a problem with adding such kind of hooks to db-migrate, currently db-migrate does not have any hooks to intercept such steps like you just explained, so this would be a new feature. If you really need this now, you can go ahead and create a PR for this, that feature wouldn't be that big though.

[mpalmerlee]

Ok, thanks. I agree this approach wouldn't be super clean and the efficiency of the migrations would suffer, but I wanted to explore my options. I'll let you know if I end up wanting to go this route and I'll submit a PR if I do.

[wzrdtales]

To also mention, db-migrate from 0.10.x on does have a programable api, so you would be at least able to do stuff like the following:

https://github.com/db-migrate/api-examples/blob/master/promise.js

Maybe this already helps you, as if you do everytime the same thing after a single migration, it shouldn't make a difference for you if you do this same thing just once after all migrations have been executed.

[mpalmerlee]

Thanks for that, I did see that and thought about using it, although we are currently calling the db-migrate command instead of using the APIs on our webservers, we could switch to this method and leverage that feature like you mentioned.

Thanks for the help!