On 2014-12-09 16:23, Anders Blomdell wrote: > On 2014-12-09 13:18, Krishnan Parthasarathi wrote: >> All, >> >> I would like to propose refactoring of the code managing >> various daemons in glusterd. Unlike other high(er) level proposals >> about feature design, this one is at the implementation >> level. Please go through the details of the proposal below >> and share your thoughts/suggestions on the approach. >> >> ### Introduction >> >> Glusterd manages GlusterFS daemons providing services like NFS, Proactive >> self-heal, Quota, User servicable snapshots etc. Following are some of the >> aspects that come under daemon management. >> >> - Connection Management >> - unix domain sockets based channel for internal communication >> - Methods - connect, disconnect, notify >> >> - Process Management >> - pidfile to detect if the daemon is running >> - Environment; run-dir, svc-dir, log-dir etc. >> - Methods - start, stop, status, kill >> >> - Daemon-specific Management >> >> Currently, the daemon management code is fragmented and doesn't elicit the >> structure described above. This results in further fragmentation since new >> developers may not identify common patterns, worse even, they won't be able to >> do anything about it. >> >> This proposal aims to do the following, >> >> - Provide an abstract data type that encapsulates what is common among daemons >> that are managed by glusterd. >> >> - 'Port' existing code to make use of the abstract type. This would help in >> making this change self-documented to an extent. >> >> - Prescribe a way to maintain per-feature daemon code separate to glusterd's >> common code. >> >> ### Abstract data types >> >> struct conn_mgmt { >> struct rpc_clnt *rpc; >> int (*connect) (struct conn_mgmt *self); >> int (*disconnect) (struct conn_mgmt self); >> int (*notify) (struct conn_mgmt *self, rpc_clnt_event_t *rpc_event); >> } > Great, one place to fix IPv6/IPv4 coexistence :-) Just for cross referencing: https://bugzilla.redhat.com/show_bug.cgi?id=1117886 > >> >> struct proc_mgmt { >> char svcdir[PATH_MAX]; >> char rundir[PATH_MAX]; >> char logdir[PATH_MAX]; >> char pidfile[PATH_MAX]; >> char logfile[PATH_MAX]; >> >> char volid[UUID_CANONICAL_FORM_LEN]; >> >> int (*start) (struct proc_mgmt *self, int flags); >> int (*stop) (struct proc_mgmt *self, int flags); >> int (*is_running) (struct proc_mgmt *self); >> int (*kill) (struct proc_mgmt *self, int flags); >> >> } >> >> Feature authors can define data type representing their service by implementing >> the above 'abstract' class. For e.g, >> >> struct my_service { >> char name[PATH_MAX]; >> /* my_service specific data members and methods */ >> >> /* The methods in the following structures should be implemented by >> respective feature authors */ >> >> struct conn_mgmt conn; >> struct proc_mgmt proc; >> } >> >> ### Code structure guidelines >> >> Each feature that introduces a daemon would implement the abstract data type. >> The implementations should be in separate files named appropriately. The intent >> is to avoid feature specific code to leak into common glusterd codebase. >> glusterd-utils.c is testament to such practices in the past. >> >> For e.g, >> [kp@trantor glusterd]$ tree >> . >> └── src >> ├── glusterd-conn-mgmt.c >> ├── glusterd-conn-mgmt.h >> ├── glusterd-proc-mgmt.c >> ├── glusterd-proc-mgmt.h >> ├── my-feature-service.c >> └── my-feature-service.h >> >> [kp@trantor glusterd]$ cat src/my-feature-service.h >> #include "glusterd-conn-mgmt.h" >> #include "glusterd-proc-mgmt.h" >> >> ... >> [rest of the code elided] >> >> ### Bibliography >> >> - Object-oriented design patterns in the kernel, part 1 - http://lwn.net/Articles/444910/ >> - Object-oriented design patterns in the kernel, part 2 - http://lwn.net/Articles/446317/ >> >> >> thanks, >> kp >> _______________________________________________ >> Gluster-devel mailing list >> Gluster-devel@xxxxxxxxxxx >> http://supercolony.gluster.org/mailman/listinfo/gluster-devel >> > > /Anders > -- Anders Blomdell Email: anders.blomdell@xxxxxxxxxxxxxx Department of Automatic Control Lund University Phone: +46 46 222 4625 P.O. Box 118 Fax: +46 46 138118 SE-221 00 Lund, Sweden _______________________________________________ Gluster-devel mailing list Gluster-devel@xxxxxxxxxxx http://supercolony.gluster.org/mailman/listinfo/gluster-devel