Re: [pgadmin4][patch] Initial patch to decouple from ACI Tree

Hello Khushboo

On Mon, Apr 9, 2018 at 1:59 AM Khushboo Vashi <
khushboo(dot)vashi(at)enterprisedb(dot)com> wrote:

> Hi Joao,
>
> I have reviewed your patch and have some suggestions.
>
> On Sat, Apr 7, 2018 at 12:43 AM, Joao De Almeida Pereira <
> jdealmeidapereira(at)pivotal(dot)io> wrote:
>
>> Hello Murtuza/Dave,
>> Yes now the extracted functions are spread into different files. The
>> intent would be to make the files as small as possible, and also to group
>> and name them in a way that would be easy to understand what each file is
>> doing without the need of opening it.
>> As a example:
>> static/js/backup will contain all the backup related functionality
>> inside of this folder we can see the file:
>>
> menu_utils.js At this moment in time we decided to group all the
>> functions that are related to the menu, but we can split that also if we
>> believe it is easier to see.
>>
> It's really very good to see the separated code for backup module. As we
> have done for backup, we would like do it for other PG utilities like
> restore, maintenance etc.
> Considering this, we should separate the code in a way that some of the
> common functionalities can be used for other modules like menu (as you
> have mentioned above), dialogue factory etc.
> Also, I think these functionalities should be in their respective static
> folder instead of pgadmin/static.
>

About the location of the files. The move of the files to pgadmin/static/js
was made on purpose in order to clearly separate Javascript from python
code.
The rational behind it was
- Create a clear separation between the backend and frontend
- Having Javascript code concentrated in a single place, hopefully, will
encourage to developers to look for a functionality, that is already
implemented in another modules, because they are right there. (When we
started this journey we realized that the 'nodes' have a big groups of code
that could be shared, but because the Javascript is spread everywhere it is
much harder to look for it)

There are some drawbacks of this separation:
- When creating a new module we will need to put the javascript in a
separate location from the backend code

>
>
>> static/js/datagrid folder contains all the datagrid related functionality
>>
> Same as backup module, this should be in it's respective static/js folder.
>
>> Inside of the folder we can see the files:
>> get_panel_title.js is responsible for retrieving the name of the panel
>> show_data.js is responsible for showing the datagrid
>> show_query_tool.js is responsible for showing the query tool
>>
>> Does this structure make sense?
>> Can you give an example of a comment that you think is missing and that
>> could help?
>>
>> As a personal note, unless the algorithm is very obscure or very
>> complicated, I believe that if the code needs comments it is a signal that
>> something needs to change in terms of naming, structure of the part in
>> question. This being said, I am open to add some comments that might help
>> people.
>>
> You are right, with the help of naming convention and structure of the
> code, any one can get the idea about the code. But it is very useful to
> understand the code
> very easily with the proper comments especially when there are multiple
> developers working on a single project.
>
> I found some of the places where it would be great to have comments.
>
> - treeMenu: new tree.Tree() in a browser.js
> - tree.js (especially Tree class)
>
About the comment point I need a more clear understanding on what kind of
comments you are looking for. Because when you read the function names you
understand the intent, what they are doing. The parameters also explain
what you need to pass into them.

If what you are looking for in these comments is the reasoning being the
change itself, then that should be present in the commit message. Specially
because this is going to be a very big patch with a very big number of
changes.

>
> Thanks
>> Joao
>> ​
>>
>> Thanks,
> Khushboo
>
>>
>> On Fri, Apr 6, 2018 at 4:48 AM Murtuza Zabuawala <
>> murtuza(dot)zabuawala(at)enterprisedb(dot)com> wrote:
>>
>>> Hi Joao,
>>>
>>> Patch looks good and working as expected.
>>>
>>> I also agree with Dave, Can we please add some comments in each file
>>> which can help us to understand the flow, I'm saying because now the code
>>> is segregated in so many separate files it will be hard to keep track of
>>> the flow from one file to another when debugging.
>>>
>>>
>>> --
>>> Regards,
>>> Murtuza Zabuawala
>>> EnterpriseDB: http://www.enterprisedb.com
>>> The Enterprise PostgreSQL Company
>>>
>>>
>>> On Thu, Apr 5, 2018 at 7:08 PM, Joao De Almeida Pereira <
>>> jdealmeidapereira(at)pivotal(dot)io> wrote:
>>>
>>>> Hi Khushboo,
>>>> Attached you can find both patches rebased
>>>>
>>>> Thanks
>>>>
>>>>
>>>> On Thu, Apr 5, 2018 at 6:31 AM Khushboo Vashi <
>>>> khushboo(dot)vashi(at)enterprisedb(dot)com> wrote:
>>>>
>>>>> Hi Joao,
>>>>>
>>>>> Can you please rebase the second patch?
>>>>>
>>>>> Thanks,
>>>>> Khushboo
>>>>>
>>>>>
>>>>> On Tue, Apr 3, 2018 at 12:15 AM, Joao De Almeida Pereira <
>>>>> jdealmeidapereira(at)pivotal(dot)io> wrote:
>>>>>
>>>>>> Hi Hackers,
>>>>>>
>>>>>> Attached you can find the patch that will start to decouple pgAdmin
>>>>>> from ACITree library.
>>>>>> This patch is intended to be merged after 3.0, because we do not want
>>>>>> to cause any entropy or delay the release, but we want to start the
>>>>>> discussion and show some code.
>>>>>>
>>>>>> This job that we started is a massive tech debt chore that will take
>>>>>> some time to finalize and we would love the help of the community to do it.
>>>>>>
>>>>>> *Summary of the patch:*
>>>>>> 0001 patch:
>>>>>> - Creates a new tree that will allow us to create a separation
>>>>>> between the application and ACI Tree
>>>>>> - Creates a Fake Tree (Test double, for reference on the available
>>>>>> test doubles: https://martinfowler.com/bliki/TestDouble.html) that
>>>>>> can be used to inplace to replace the ACITree and also encapsulate the new
>>>>>> tree behavior on our tests
>>>>>> - Adds tests for all the tree functionalities
>>>>>>
>>>>>> 0002 patch:
>>>>>> - Extracts, refactors, adds tests and remove dependency from ACI
>>>>>> Tree on:
>>>>>> - getTreeNodeHierarchy
>>>>>> - on backup.js: menu_enabled, menu_enabled_server,
>>>>>> start_backup_global_server, backup_objects
>>>>>> - on datagrid.js: show_data_grid, get_panel_title, show_query_tool
>>>>>> - Start using sprintf-js as Underscore.String is deprecating sprintf
>>>>>> function
>>>>>>
>>>>>> This patch represents only 10 calls to ACITree.itemData out of 176
>>>>>> that are spread around our code
>>>>>>
>>>>>>
>>>>>> *In Depth look on the process behind the patch:*
>>>>>>
>>>>>> We started writing this patch with the idea that we need to decouple
>>>>>> pgAdmin4 from ACITree, because ACITree is no longer supported, the
>>>>>> documentation is non existent and ACITree is no longer being actively
>>>>>> developed.
>>>>>>
>>>>>> Our process:
>>>>>> 1. We "randomly" selected a function that is part of the ACITree.
>>>>>> From this point we decided to replace that function with our own version.
>>>>>> The function that we choose was "itemData".
>>>>>> The function gives us all the "data" that a specific node of the tree
>>>>>> find.
>>>>>> Given in order to replace the tree we would need to have a function
>>>>>> that would give us the same information. We had 2 options:
>>>>>> a) Create a tree with a function called itemData
>>>>>> Pros:
>>>>>> - At first view this was the simpler solution
>>>>>> - Would keep the status quo
>>>>>> Cons:
>>>>>> - Not a OOP approach
>>>>>> - Not very flexible
>>>>>> b) Create a tree that would return a node given an ID and then the
>>>>>> node would be responsible for giving it's data.
>>>>>> Pros:
>>>>>> - OOP Approach
>>>>>> - More flexible and we do not need to bring the tree around, just a
>>>>>> node
>>>>>> Cons:
>>>>>> - Break the current status quo
>>>>>>
>>>>>> Given these 2 options we decided to go for a more OOP approach
>>>>>> creating a Tree and a TreeNode classes, that in the future will be renamed
>>>>>> to ACITreeWrapper and TreeNode.
>>>>>>
>>>>>> 2. After we decided on the starting point we searched for occurrences
>>>>>> of the function "itemData" and we found out that there were 303 occurrences
>>>>>> of "itemData" in the code and roughly 176 calls to the function itself
>>>>>> (some of the hits were variable names).
>>>>>>
>>>>>> 3. We selected the first file on the search and found the function
>>>>>> that was responsible for calling the itemData function.
>>>>>>
>>>>>> 4. Extracted the function to a separate file
>>>>>>
>>>>>> 5. Wrap this function with tests
>>>>>>
>>>>>> 6. Refactor the function to ES6, give more declarative names to
>>>>>> variables and break the functions into smaller chunks
>>>>>>
>>>>>> 7. When all the tests were passing we replaced ACITree with our Tree
>>>>>>
>>>>>> 8. We ensured that all tests were passing
>>>>>>
>>>>>> 9. Remove function from the original file and use the new function
>>>>>>
>>>>>> 10. Ensure everything still works
>>>>>>
>>>>>> 11. Find the next function and execute from step 4 until all the
>>>>>> functions are replaced, refactored and tested.
>>>>>>
>>>>>> As you can see by the process this is a pretty huge undertake,
>>>>>> because of the number of calls to the function. This is just the first step
>>>>>> on the direction of completely isolating the ACITree so that we can solve
>>>>>> the problem with a large number of elements on the tree.
>>>>>>
>>>>>> *What is on our radar that we need to address:*
>>>>>> - Finish the complete decoupling of the ACITree
>>>>>> - Performance of the current tree implementation
>>>>>> - Tweak the naming of the Tree class to explicitly tell us this is
>>>>>> to use only with ACITree.
>>>>>>
>>>>>>
>>>>>> Thanks
>>>>>> Joao
>>>>>>
>>>>>>
>>>>>
>>>