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From Antonio Fornié Casarrubios <antonio.for...@gmail.com>
Subject Re: [PROPOSAL][QUESTION] Map parameters in API Commands
Date Mon, 03 Mar 2014 00:31:51 GMT
Hi Alena,

The reasons for this strange format? I don't know. There doesn't seem to be
one. After asking on my team and in the dev list I thought perhaps you
could know. It seems we all see it strange and nobody knows why. But of
course, if it is for reasons I will stop the change.



And about the DB, you are right, in the DB is not like I said. But you can
have this in a table row field:
{0={value=Toronto,key=City}}
for some tables. I think there are two cases:

1- params in wich the get method fixes the params on the fly. In these of
course the strange format is not propagated anymore. But this is still
wrong: the format itself before the get is invoked, the time spent on
fixing something that should be a normal Map from the begining (each time
the get method is invoked) and mainly the fact that these get methods that
fix the map on the fly are copies of each other: instead of fixing the
structure in one method, the are plenty of methods almost identical copying
and pasting the same lines. Some times the same method twice in the same
cmd class for two Map params (look CreateNetworkOfferingCmd
#getServiceCapabilities and #getServiceProviders).

2- params in which the get method returns the map as it is. With the
strange format. For example,
Cloudmonkey command
create networkoffering ... tags[0].key="City" tags[0].value="Toronto"

You store in the table network_offeringstags, field tags, the String:
{0={value=Toronto,key=City}}
(including brackets and all)

So knowing all this I guess you agree this should be refactored... unless
at some point the strange format is needed. But after looking for it
everywhere I didn't find any place where it was. I already did the change
and tested most of the cases and it all seems to work.


It would be great if once I upload the patch somebody could help me double
check that it doesn't brake anything, not only reviewing to code. I did
plenty of tests of many kinds, but I cannot be sure that I am covering
enough. Further, there seem to be several places where the code expects the
strange format.
->ConfigurationManagerImpl line 1545


Thanks. Cheers
Antonio


2014-02-28 18:44 GMT+01:00 Alena Prokharchyk <Alena.Prokharchyk@citrix.com>:

>
>
>   From: Antonio Fornié Casarrubios <antonio.fornie@gmail.com>
> Date: Friday, February 28, 2014 at 2:09 AM
> To: Rohit Yadav <rohityadav89@gmail.com>, cloudstack <
> dev@cloudstack.apache.org>, Alena Prokharchyk <
> alena.prokharchyk@citrix.com>
> Subject: Re: [PROPOSAL][QUESTION] Map parameters in API Commands
>
>   Hi Alena,
>
>  I would like to know your opinion on this change. Mainly consists on:
> 1- Change the way we store the Map params after unpackParams in order to
> have, for each Map param, a Map<String, String> instead of Map<String,
> Map<String, Object>>.
>
>
>  -Antonio, what was the reason for storing the parameter in the old
> format to begin with? Where there any case where we actually needed a map
> of map parameters?
>
>

>
>  2- There are many commands that fix this strange format on demand on
> their getters, so they do the conversion there. Since I already have the
> final format I replace these getters with just
> getTags(){ return this.tags;}
>
>  3- Persistence of these Map params. This last change is more tricky and
> error-prone but the previous two would brake the functionality without it.
> Actually it doesn't seem that I should change this for all the cases, given
> that for some commands the current behavior is storing in the DB the Map as
> it comes, so after the change it will just do the same and thus retrieve it
> with the right format. So, although in the tables we move from
> ------
> key | City
> ------
> value | The Hague
> ------
>
>  to
> ------
> City | The Hague
> ------
>
>  then in memory, after DB read, we will just have the proper format again
> (Map<String, String>). Is that right?
>
>
>
>    - in what table do you see key name being a field name? I've looked at
>    various *_details tables, as well as resource_tag table, everywhere we have
>    key/value fields where we store key and the value respectfully:
>
>  mysql> desc user_Vm_details;
> +---------+---------------------+------+-----+---------+----------------+
> | Field   | Type                | Null | Key | Default | Extra          |
> +---------+---------------------+------+-----+---------+----------------+
> | id      | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
> | vm_id   | bigint(20) unsigned | NO   | MUL | NULL    |                |
> | name    | varchar(255)        | NO   |     | NULL    |                |
> | value   | varchar(1024)       | NO   |     | NULL    |                |
> | display | tinyint(1)          | NO   |     | 1       |                |
> +---------+---------------------+------+-----+---------+----------------+
> 5 rows in set (0.01 sec)
>
>  mysql> desc resource_tags;
>
> +---------------+---------------------+------+-----+---------+----------------+
> | Field         | Type                | Null | Key | Default | Extra
>    |
>
> +---------------+---------------------+------+-----+---------+----------------+
> | id            | bigint(20) unsigned | NO   | PRI | NULL    |
> auto_increment |
> | uuid          | varchar(40)         | YES  | UNI | NULL    |
>    |
> | key           | varchar(255)        | YES  |     | NULL    |
>    |
> | value         | varchar(255)        | YES  |     | NULL    |
>    |
> | resource_id   | bigint(20) unsigned | NO   | MUL | NULL    |
>    |
> | resource_uuid | varchar(40)         | YES  |     | NULL    |
>    |
> | resource_type | varchar(255)        | YES  |     | NULL    |
>    |
> | customer      | varchar(255)        | YES  |     | NULL    |
>    |
> | domain_id     | bigint(20) unsigned | NO   | MUL | NULL    |
>    |
> | account_id    | bigint(20) unsigned | NO   | MUL | NULL    |
>    |
>
> +---------------+---------------------+------+-----+---------+----------------+
>
>
>  4- The last change should be related to any code expecting the old
> format, that will fail with the new one. I guess UI will be an example of
> that, but I didn't check yet. If the JS code receives the new Map
> serialized, then chances are this will break it, right? Can you tell your
> thoughts on this? Can you tell me places I should check first to confirm
> this guess?
>
>
>   - Its not just about the uI> You should never break the API backwards
> compatibility. Remember that lots of third party vendors use our APIs, not
> the UI. As long as we support the old format, introducing the new one
> shouldn't be a problem.
>
>
>
>  Considering it all, do you think this change is worth it? For me this
> seems to be something that was wrong from the beginning and it should have
> been changed before the mess got spread. But know, although I want to fix
> it, I'm afraid this involves touching too many things in order to fix
> something that looks horrible but seems to be actually working and I don't
> want to break.
>
>  Thanks. Cheers
> Antonio
>
>
>
> 2014-02-12 23:32 GMT+01:00 Rohit Yadav <rohityadav89@gmail.com>:
>
>> On Wed, Feb 12, 2014 at 9:52 PM, Antonio Fornié Casarrubios
>> <antonio.fornie@gmail.com> wrote:
>> > Hi Rohit,
>> >
>> > I didn't mean changing the format of the HTTP request, but only
>> changing the
>> > intermediate format in which we keep it in the property of the Command
>> > class. I mentioned the format in the request just to explain what I
>> meant.
>> >
>> > My proposal is to leave the request format as it is, but then when the
>> > method "apiDispatcher#setFieldValue" parses the map and assign it to the
>> > property, do it in a normal way: which is a Map<String, String> instead
>> of a
>> > Map<String, Map<String, Object>> as it is now. And then, our getter
>> methods
>> > (like CreateTagsCommand#GetTag) will be just a normal getter that
>> doesn't
>> > need to transform the structure on the fly.
>>
>>  Cool, let's request the present API layer maintainer(s) and other
>> folks in the community to comment.
>>
>> Regards.
>>
>> >
>> > Thanks, cheers
>> > antonio
>> >
>> >
>> > 2014-02-11 17:38 GMT+01:00 Rohit Yadav <rohityadav89@gmail.com>:
>> >
>> >> Hi Antonio,
>> >>
>> >> On Tue, Feb 11, 2014 at 9:57 PM, Antonio Fornié Casarrubios
>> >> <antonio.fornie@gmail.com> wrote:
>> >> > Hi all,
>> >> >
>> >> > When invoking a CS API command that has parameters of type Map, the
>> >> > request
>> >> > will be something like this:
>> >> >
>> >> >
>> URL/api?command=createTags&tags[0].key=region&tags[0].value=canada&tags[1].key=name&tags[1].value=bob
>> >> >
>> >> > in order to send a Map with the pairs:
>> >> >
>> >> > tags{
>> >> >    region : "canada",
>> >> >    name : "bob"
>> >> > }
>> >> >
>> >> > Then in the server side the parameters go through several stages
>> (IMHO
>> >> > too
>> >> > many), and have different formats. At some point
>> >> >
>> >> > apiDispatcher#setFieldValue
>> >> >
>> >> > will assign the value to the command property (CreateTagsCmd#tag in
>> the
>> >> > example) in a VERY strange way:
>> >> >
>> >> > CreateTagsCmd#tag = {
>> >> >    0 : {
>> >> >       "key" : "region",
>> >> >       "value" : "canada"
>> >> >    },
>> >> >    1 : {
>> >> >       "key" : "name",
>> >> >       "value" : "bob"
>> >> >    }
>> >> > }
>> >> >
>> >> > This is true for several Cmd classes. And the funny thing is they
>> >> > usually
>> >> > provide a public getter method to get the Map in an already
>> "normalized"
>> >> > structure. The problem is we have this method again a again in each
>> of
>> >> > these commands, only with different name depending on what property
>> the
>> >> > get, and the body is almost copy and pasted. so my next refactoring
>> >> > would
>> >> > be to have a generic method only once in BaseCmd so that all
>> subclasses
>> >> > can
>> >> > reuse it for their Map getters. Pretty obvious, but...
>> >>
>> >> This is a well know issue and is such a pain, both for the users of
>> >> the API to create this API and the programmer who have to put hack at
>> >> the backend to extract the map.
>> >>
>> >> > Is it really necessary to have this strange format? Wouldn't it be
>> much
>> >> > better to just store it in a more normal way from the beginning, and
>> >> > have
>> >> > the getters just standard getters? Does it have any use to have those
>> >> > Maps
>> >> > of Maps?
>> >>
>> >> Changing the API will break many client so no one attempted it for
>> >> keeping backward-compatibility I think.
>> >>
>> >> The HTTP RFC states that if same keys are sent in param they must be
>> >> received as an array. For example, /api?q=1&q=2&q=3 should received
q
>> >> = [1,2,3] which is what we're not doing.
>> >>
>> >> We should do that and this way we can capture maps using keys and
>> >> values in order, so for example,
>> >> /api?q.key1=value1&q.key2=value2&q.key1=value3&q.key2=value4
should be
>> >> received as as array of maps: [{key1: value1, key2: value2},
>> >> {key3:value3, key4: value4}] etc.
>> >>
>> >> I think it does not have to be maps of maps, but since our API is
>> >> query based these ugly hacks were invented. We should definitely get
>> >> rid of them, and perhaps work on the RESTful API layer, cloud-engine
>> >> and other good stuff we were talking about more than a year ago and
>> >> deprecate the present query API over next few years. Thoughts, flames?
>> >>
>> >> Regards.
>> >>
>> >> >
>> >> > Thanks. Cheers
>> >> > Antonio Fornie
>> >> > Schuberg Philis - MCE
>> >
>> >
>>
>
>

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