There is requirement connecting to RADOS cluster by Golang, and the sub-project
go-ceph(https://github.com/ceph/go-ceph) is the first solution. It uses cgo linking the
librados library and works OK. I used go-ceph in one project, there are some problems
annoying me:
The connection created to the RADOS cluster must be closed explicitly, because golang
runtime GC does not care about it. If your application holds a global connection and does
not close, it will be a waste of resource of the RADOS cluster. Otherwise, you need to
implement a connection pool for management, which increases complexity and needs a strong
testing.
librados is implemented with C/C++ and pthread thread model, and it heavily depends on the
low-level messenger implementation. What I used in my project is the luminous version, and
it will create 14 new threads when creating a connection to the RADOS cluster(use pstack
on centos7). So the mixed threads used by the golang runtime and librados causes the
problem
here(https://stackoverflow.com/questions/47466139/there-are-many-threads-re…
).
The golang program must depend on the librados when compiling and running, it decreases
the maintainability compared with common static-built golang program.
There are also some problems if you use go-ceph in your golang project, such as the
messenger layer is not efficient as golang. There is every reason to implement the gorados
- pure go client to connect RADOS cluster - to make ceph as a backend storage in
production-level golang project directly. I make this idea as a fact, and provide the
draft startup on github:
https://github.com/oshynsong/gorados. It implements the cephx
protocol to connect the monitor, and needs more development. Welcome to join me and I hope
gorados as a sub-project of ceph!