Hi Thierry + @all,
I'd like to play with the new lib389 and try to split DirSrv in two layers:
- the "old approach" DSAdmin for TCP communication
- DirSrv implementing your interface
essentially I would put
class DirSrv(DSAdmin):
# ...new stuff go here ...
class DSAdmin(SimpleLDAPObject):
# TCP stuff goes here
Can you please tell me:
1- how to run tests
2- which tests should work
3- which is the test environment.
Thx+Peace,
R.
On Thursday 09 January 2014 10:29:10 thierry bordaz wrote:
> On 01/08/2014 12:54 PM, Roberto Polli wrote:
> > Hi Thierry,
> >
> > before all sorry if in the rest of the answer I may seem too direct. All I
> > say is obviously imh(opinion|experience) Time is a tyrant :(
> >
> > On Friday 03 January 2014 16:36:17 thierry bordaz wrote:
> >> Thanks, I also wish you an happy new year and you recover well. It
> >> is great to talk to you again :-) .
> >
> > Thx++!
> >
> >> I am quite novice with python and my first approach was to use it as
> >> a real object oriented language,
> >
> > It *is* a real OOL ;)
> >
> >> it is a
> >>
> >> common use to wrap methods of class and rather use python as a
> >> functional language (e.g. self.backend.setProperties(...) rather
> >> than 'backend=Backend(); backend.setProperties(..) ')
> >
> > I'm not indepth with functional programming. Why do you think that's a
> > functional approach?
> >
> >> ...the 'object'...are... the configuration object stored in
> >> 'cn=config'. So it prevents the problem of synchronizing the python
> >> object with the 'cn=config' object.
> >
> > To me that's mostly an ORM approach: in any case that's ok
>
> Hi Roberto,
>
> I will try to answer your concerns but as all of them are valid I
> will only give some reasons for the approach I choose.
>
> About OOL vs. functional programing this is not IMH that important.
> For example for an instance with N replicas, we can imagine DSAdmin
> having N Replica/Backend/Suffix/MappingTree... objects. Instead we
> have only one, let's say Replica object, allocated in
> __add_brookers__ but this object is not a real object but just gives
> access all methods of Replica class.
> As I said, having N Replica objects brings a big drawback to
> synchronize the objects with what is in the server config. So I
> think the __add_brookers__ approach is better.
>
> >> So the only remaining object is
> >> the DS instance (dirsrv/dsadmin) and methods to access its config.
> >>
> >> Does it prevent to use fake directory ? I am not enough familiar
> >> with fakeldap, would you give me an example of why the current
> >> implement would not work with fakeldap ?
> >
> > Let's see how do we setup the client now:
> > args = {SER_HOST: LOCALHOST,
> >
> > SER_PORT: INSTANCE_PORT,
> > SER_DEPLOYED_DIR: INSTANCE_PREFIX,
> > SER_SERVERID_PROP: INSTANCE_SERVERID
> > }
> >
> > 1- instance = DirSrv(verbose=False)
> > 2- instance.allocate(args)
> > 3- if instance.exists(): instance.delete()
> > 4- instance.create()
> > 5- instance.open()
> >
> > That's quite different from the (imho cleaner) old approach - similar to
> > the>
> > SimpleLDAPObject superclass:
> > args = {'host': LOCALHOST, 'sslport': 10636}
> > 1- instance = DSAdmin(**args)
>
> I agree with you DSAdmin approach looks definitely simpler. Now
> there is some magic behind DSAdmin().
> It actually checks if the instance exists, if not it creates it,
> then it opens a connection to it.
> What I wanted to do in a lib is to give an interface to each
> individual action. We may want to create an instance without
> establishing a connection to it, or (re)create an instance even if
> one already exists.
> Your point is valid, we need something simple. So what about adding
> a new interface to DirSrv (e.g. NewAndConnect) that would do all the
> steps 1-5 ?
>
> > Obviously there are plenty of functionalities DSAdmin didn't implement: I
> > would have put those functionalities (eg. filesystem related, instance
> > creation & removal) in the DSAdminTool class.
> >
> > You may ask: why having two class DSAdminTool and DSAdmin instead of just
> > one? 1- clear design: as DSAdmin extends SimpleLDAPObject, it should
> > require just a tcp connection (like SimpleLDAPObject). In this way I can
> > use a mock ldap implementation to test the LDAP behavior of DSAdmin.
>
> DirSrv also extends SimpleLDAPObject and wrap all its methods
> (search/add...) what would prevent it to be use as mock ldap ?
>
> > 2- all the functionalities requiring filesystem access and instance
> > management (eg. outside LDAP scope) couldn't be tested by a mock ldap
> > implementation, so we can just extend the mock for those functionalities.
>
> ok
>
> > 3- As extending classes (or using mix-ins) in python is really smooth,
> > this
> > approach would lead to the same usage patterns we have now, but with a
> > separate, tcp oriented DSAdmin class.
>
> Yes that looks very smart. Couldn't it been done with DirSrv that in
> my understanding is similar to DSAdmin ? (except specific interface
> to create/open).
>
> >> About the shift of parameters to dictionary I think both approaches
> >> are valid.
> >> ... I used a dictionary to pass
> >> the properties (rather than functions arguments) mainly because some
> >> resource may have many properties, also because all the
> >> set-<resource>-prop function have a similar interface.
> >
> > I understand your choice in the view of the CLI. I just think it shouldn't
> > influence the layout of a class which extends SimpleLDAPObject (see §3 of
> > the previous statement).
>
> Is your concern (parameters vs dictionary) specific to
> DirSrv/DSAdmin class ? Have you the same concern for others classes
> (Replica, Backend, MT, Agreement..) ?
>
> > Here's my rationale of why I stand for the parameter-based (choice made
> > after>
> > a discussion on #python):
> > 1- parameter-based approach is self-documenting;
> > 2- interactive python self-completes parameters, so you can use it
> >
> > without knowing the whole interface;
> >
> > 3- a parameter-based function can take a **dict input, converse is not
> >
> > true;
> >
> > 4- parameter-based saves you from managing default values;
> > 5- parameter-based makes clear which are the default values;
>
> I agree with all your points. Now the status is not that bad with
> dictionary when you are using an IDE.
> It shows the header comment of the function you keyed and that
> header can contain the args list and explanation.
>
> Note that an benefit of dictionaries (to provide the
> properties/attribute) is that it standardizes the interface for all
> classes. Any create/set-prop methods of any class takes a set of of
> properties through a dictionary.
> With args the interface will vary a lot from let's say MT that have
> few attributes to RA/DirSrv that have a lot of attributes.
>
> About the default value, yes parameters brings an advantage. Now
> this is an advantage for lib389 implementation not for lib389 user.
>
> > The parameter approach can easily be wrapped elsewhere:
> >
> > class DSAdmin(..):
> > def __init__(host='localhost', port=389, furtherargs={}):
> > # doit
> >
> > class DirSrv():
> > def allocate(allargs):
> > # put the following code in an utility function
> > proxy_params = DSAdmin.__init__.func_code.co_varnames
> > params = {k:v for k,v in allargs.items() if k in
> > proxy_parameters}
> > params['furtherargs'] = {k:v for k,v in allargs.items() if k
> > not in
> >
> > proxy_parameters}
> >
> > self.instance = DSAdmin(**params)
>
> Yes 'allocate' is then similar to 'NewAndConnect' I said before.
>
> Let me know.
> Regards
> thierry
>
> > Moreover the utility function could even be used for mapping the human-
> > readable values to the internal ones.
> >
> > Let me know + Peace,
> > R.
> >
> >> Just let me explain why I choose dictionary, it comes
> >>
> >> from what could be future CLI.
> >> for example we may have a CLI pattern like:
> >>
> >> <admin_cmd> <verb-resource> [parameters] [options]
> >>
> >> admin_cmd::= "dsadmin"
> >> verb-resource::= <verb-suffix> | <verb-replication> | <verb-backend>
> >>
> >> |...
> >>
> >> <verb-suffix> ::= list-suffix | create-suffix | delete-suffix...
> >> parameter::= <parameters to connect to the DS instance (port,
> >> credential..)>
> >> options::= <option to process the command and also some properties>
> >>
> >> Then we have specific <verb-resource> to define the resource
> >> properties (entry cache size, directory path, type of replica...)
> >>
> >> They are set-suffix-prop, set-backend-prop...
> >> Basically once the resource has been created (with some properties),
> >> any 'properties' of the resource can be read/write by
> >> set/get-<resource>-prop.
> >>
> >> So for the CLI (or other admin application) we need to send
> >> prop:value to an instance. prop are then available in an include
> >> file, but in a human-readable way (like 'suffix') rather than in an
> >> attribute way (like 'nsds5replicaroot')
> >>
> >> I do not know if I answer correctly your concerns. Just let me know
> >> if I missed your questions.
> >>
> >> regards
> >> thierry
> >>
> >> On 01/03/2014 01:10 PM, Roberto Polli wrote:
> >>> Hi Everybody!
> >>>
> >>> First of all Happy New Year, hope it will be filled of fun!
> >>>
> >>> I am really sorry for not supporting you for so long, but as I told you
> >>> I
> >>> can't still spend too much extra-work time coding :(.
> >>>
> >>> I saw the evolution of the library and I'm glad of the new
> >>> functionalities
> >>> and the split-up of the brooker in various files.
> >>>
> >>> On the other hand I think that the new interface changes don't go on the
> >>> simplicity/usability path, so I'd like to understand your targets and
> >>> give
> >>> some suggestions.
> >>>
> >>> On Thursday 12 December 2013 21:58:12 thierry bordaz wrote:
> >>>> Ticket https://fedorahosted.org/389/ticket/47625 changes the interface
> >>>> of DirSrv.
> >>>> This ticket is the porting side of the test cases to the new interface
> >>>
> >>> 1- The new interface initialization is substantially different from a
> >>> standard>
> >>>
> >>> client-server interface. A user expects to instantiate objects like
this:
> >>> # client = Telnet(host, port, credential)
> >>>
> >>> 2- This is quite the behavior of the LDAPObject superclass, which I
> >>> would
> >>> like to retain so that we can use fakeldaps for unittest
> >>>
> >>> 3- The standard DirSrv.__init__ (and the same is valid for other
> >>> methods),
> >>> containing a set of parameters is intrinsically documented. Shifting
> >>> core
> >>>
> >>> parameters in dictionaries:
> >>> a- de-documents parameters and default values outside the method
> >>> signature;
> >>> b- requires parsing and setting of default values;
> >>> Python allows to retain the dict-style stuff using the **magic, which
> >>> I
> >>> would>
> >>>
> >>> embrace in this case.
> >>>
> >>> The new Interface Layer would be easily implemented in a subclass.
> >>>
> >>> Let me know + Peace (and sorry again for my absence),
> >>> R.
> >>>
> >>>> https://fedorahosted.org/389/attachment/ticket/47628/0001-Ticket-47628-> >>>> po
> >>>> rt-> testcases-to-new-DirSrv-interface.patch
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Roberto Polli
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