I'm wondering if Flyway allows the use a master file to re-enforce the execution orders of procedures, functions, views and triggers in repeatable migrations? Currently I have an in-house tool that generates master files for these objects so that they can be installed without errors (resolves the inter-dependency between them).
Has anyone had similar experience and how did you handle this?
Thanks!
When Flyway finds multiple repeatable migrations that need to run (because they are new or have been modified), Flyway executes them in the alphabetical order of their descriptions.
This should easily allow you to achieve something similar to what your in-house tool did with its master file.
Related
We have not used Flyway from the beginning of our project. We are at an advanced state of development. An expert review has suggested to use Flyway in our project.
The problem is that we have moved part of our services (microservices) into another testing environment as well.
What is the best way to properly implement Flyway? The requirements are:
In Development environment, no need to alter the schema which is already existing. But all new scripts should be done using Flyway.
In Testing environment, no need to alter the schema which is already existing. But what is not available in testing environment should be created automatically using Flyway when we do migrate project from Dev to test.
When we do migration to a totally new envrionment (UAT, Production etc) the entire schema should be created automatically using Flyway.
From the documentation, what I understood is:
Take a backup of the development schema (both DDL and DML) as SQL script files, give a file name like V1_0_1__initial.sql.
Clean the development database using "flyway clean".
Baseline the Development database "flyway baseline -baselineversion=1.0.0"
Now, execute "flyway migrate" which will apply the SQL script file V1_0_1__initial.sql.
Any new scripts should be written with higher version numbers (like V2_0_1__account_table.sql)
Is this the correct way or is there any better way to do this?
The problem is that I have a test database where we have different set of data (Data in Dev and test are different and I would like to keep the data as it is in both the environments). If so, is it good to separate the DDL and DML in different script files when we take it from the Dev environment and apply them separately in each environment? The DML can be added manually as required; but bit confused if I am doing the right thing.
Thanks in advance.
So, there are actually two questions here. Data management and Flyway management.
In terms of data management, yes, that should be a separate thing. Data grows and grows. Trying to manage data, beyond simple lookup tables, from source control quickly becomes very problematic. Not to mention that you want different data in different environments. This also makes automating deployments much more difficult (branching would be your friend if you insist on going this route, one branch for each data set, then deploy appropriately).
You can implement Flyway on an existing project, yes. The key is establishing the baseline. You don't have to do all the steps you outlined above. Let's say you have an existing database. You have to get the script that defines that database. That single script should include all appropriate DDL (and, if you want, DML). Name it following the Flyway standards. Something like V1.0__Baseline.sql.
With that in place, all you must do is run:
flyway baseline
That will establish your existing code base as the start point. From there, you just have to create scripts following the naming standard: V1.1xxx V2.0xxx V53000.1xxx. And run
flyway migrate
To deploy appropriate changes.
The only caveat to this is that, as the documentation states, you must ensure that all your databases match this V1.0 that you're creating and marking as the baseline. Any deviation will cause errors as you introduce new changes and migrate them into place. As long as you've got matching baseline points, you should be able to proceed with different data in different environments with no issues.
This is my how-to instruction on integration flyway with prod DB: https://delicious-snipe-938.notion.site/How-to-integrate-Flyway-with-existing-MySQL-DB-in-Prod-PostgreSQL-is-similar-1eabafa8a0e844e88205c2f32513bbbe.
The normal way of dealing with Doctrine Migrations is via the standard Commands - during development one runs the commands manually to e.g. run diffs and apply the migrations, and deployment typically involves applying them the by the same approach but automatically. Occasionally when working in a team on a local instance there are new migrations, but I've updated my source from version control rather than done a deployment, so I need to apply the new migrations manually, and I need to know that I need to do that! An improvement could be to display a warning on a rendered webpage that migrations are out of sync and action needs to be taken.
Is there a way to access the Migrations API directly in PHP/Symfony code, so that I could detect a mismatch between committed and applied migrations? I haven't found any documentation about that. I've had an initial poke around the code and it seems heavily skewed towards Commands (reasonably enough).
Firstly, updating your source code from version control, is a deployment too, and applying Doctrine Migrations should be part of that. You should create a check list of all the steps you need to do during a deployment, including rollbacks. Depending on the complexity of the application, many things could go wrong.
To answer you question, you can execute, in your code, a diff migration with the Process component and parse the output to determine if there're migrations to be applied.
I am currently using the Flyway Command Line tool to manage our scripts which will be invoked via our release process triggered from our CI Build server.
The issue is I have 274 repeatable migrations covering package specs, package bodies, functions, procedures, views and materialised views.
When I run migrate everything works as expected with migrations executing followed by any changed repeatable migrations but lets say in the next release we want to delete a object which one of the repeatable migrations maintains. For example, we want to remove the repeatable script that defined ProcedureOne (ie R__ProcedureOne.sql).
To do this I would have a new migration script (V3.1.5.1.01__DropProcedureOne.sql) but I would also remove the repeatable migration script so the object isn't created again and maintained.
However, executing flyway info shows the R__ProcedureOne.sql script with the status of MISSING.
While I agree it is missing it is a deliberate action to have it deleted as it is no longer required opposed to being misplaced.
I am aware of the migrate option ignoreMissingMigrations but i think using this introduces risk and could mask genuine missing files.
What is the general guidance on how best to remove a repeatable scripts?
I suggest that you simply keep the file but make it empty (ie zero bytes). Alternatively have a comment in the file that explains that the object it represents has been removed.
As for actually removing it, another option from what you suggested could be to update the repeatable migration to remove itself then update again to zero length. This has the advantage of being able to be replayed into an empty database; since repeatable migrations are applied after versioned the procedure in your example won't exist to be dropped. The disadvantage is running two migrations.
We have a customer with a IT-department that insist on getting database updates as scripts prior to upgrades (they want to "read" the updates before implementing them).
Being an avid user of flyway it made me think about a way of generating a script from flyway based on updates and send this script to IT. This script would at the very least need to create version table if non-existant, check version and apply needed updates. It would of course be proprietary to database vendor (in my case Oracle).
This would allow us to run updates with flyway automatically in development environments and create manual scripts for test and production.
Are anyone aware of something like that having been contemplated or endeavored before? Would it be trivial or a momentous task?
We had this exact problem when I worked at a consultancy (Intelliware) so the devs there put together some code and pushed it up to GitHub.
We tried unsuccessfully to get it included into the Flyway core repo.
https://github.com/Intelliware/flyway-script-generator
db-maintain has the notion of repeatable scripts, such as stored procedures/triggers. When there is a change to such a script it needs to be rolled out again. Flyway seemingly always checks for the filename convention. So to have a repeatable script we might need to rename the file. Is there a more efficient way of doing this?
Flyway started to support repeatable migrations in version 4.0. Repeatable migrations are reapplied every time their checksum changes and can be maintained as single files in version control.
It is your responsibility to ensure the same repeatable migration can
be applied multiple times. This usually involves making use of CREATE
OR REPLACE clauses in your DDL statements.
More details here.
This issue has come up in the Issue Tracker and in this other question.
There is currently no out of the box support for this.
Personally I would
package the repeatable actions in a stored procedure or trigger and add it to the DB as part of a regular migration
make sure this procedure/trigger gets invoked once per migration after that (could be as little a one-line statement)
ensure changes to the procedure/trigger necessary after that also happen as part of regular migrations
If that doesn't do it, feel free to star the Issue and comment with details about your use case.
Update: Repeatable scripts are now fully supported as of Flyway 4.0. See https://flywaydb.org/documentation/migration/repeatable