go

Go bindings for Motr - go/mio

go/mio Go package implements Reader / Writer interface over Motr client I/O API. This allows writing Motr client applications quickly and efficiently in the Go language.

go/mio automatically determines the optimal unit (stripe) size for the newly created object (based on the object size provided by user in the mio.Create(obj, sz) call), as well as the optimal block size for Motr I/O based on the cluster configuration. So users don't have to bother about tuning these Motr-specific parameters for each specific object to reach maximum I/O performance on it and yet don't waste space (in case of a small objects).

go/mio allows to read/write the blocks to Motr in parallel threads (see -threads option) provided there is enough buffer size to accomodate several of such blocks in one Read()/Write() request. (For example, see the source code of mcp utility and its -bsz option.)

To use go/mio in your app 1) install motr-devel pkg and 2):

import github.com/Seagate/cortx-motr/bindings/go/mio

mcp

mcp (Motr cp) utility is a client application example written in pure Go which uses go/mio package and has only 97 lines of code (as of 30 Oct 2020). It allows to copy Motr objects to/from a file or between themselves:

Usage: mcp [options] src dst

 At least one of src and dst arguments must be object id.
 The other can be file path or '-' for stdin/stdout.

  -bsz size
    	i/o buffer size (in MiB) (default 32)
  -ep endpoint
    	my endpoint address
  -hax endpoint
    	local hax endpoint address
  -off offset
    	start object i/o at offset (in KiB)
  -osz size
    	object size (in KiB)
  -pool fid
    	pool fid to create object at
  -proc fid
    	my process fid
  -prof fid
    	cluster profile fid
  -threads number
    	number of threads to use (default 1)
  -trace
    	generate m0trace.pid file
  -v	be more verbose

In order to build:

1. Build Motr first (or install pre-built motr-devel package).
2. Install Go: sudo yum install go.

Then run:

cd motr/bindings/go/mcp && go build && go install

The binary will be installed to your GOBIN directory (check with go env GOBIN or echo $(go env GOPATH)/bin).

See the usage example at this discussion thread - #285.

mkv

mkv is a trivial reference utility which can do two basic operations over Motr distributed Key-Value Store (aka Index): PUT and GET.

Usage: mkv [options] index_id key [value]

 With value present it will be PUT operation.
 Without value it will be GET operation.

  -c	create index if not present
  -d	delete the record by the key
  -ep endpoint
    	my endpoint address
  -hax endpoint
    	local hax endpoint address
  -proc fid
    	my process fid
  -prof fid
    	cluster profile fid
  -threads number
    	number of threads to use (default 1)
  -trace
    	generate m0trace.pid file
  -u	update value at the existing key
  -v	be more verbose

The steps to build and install are similar to mcp (see above).