coinstac-computation 0.62

Generic computation implementation on COINSTAC.

COINSTAC computations development made easy.

A very intuitive wrapper for writing coinstac based computations:

• Break down your computations into simple phases with automatic transition between phases.
• Add as many phases as you want.
• Even run phases that needs to be run multiple local-remote trips(iterations). See advanced use case example below.
• Installation: pip install coinstac-computation
• Add entry coinstac-computation to the requirements.txt.

---

Example: Gather max even numbers from each site

A full working use case is in the examples/basic directory where:

• Local sites filters out even numbers and sends to the remote.
• Remote finds the max across sites and returns the final result to each of the sites.
• Sites save final result.

inputspec.json data:

[
  {
    "data": {
      "value": [10, 3, 5, 6, 7, 8, 12, 38, 32, 789, 776, 441]
    }
  },
  {
    "data": {
      "value": [12, 33, 88, 61, 37, 58, 103, 3386, 312, 9, 77, 41]
    }
  }
]

Local node pipeline:

import os
from coinstac_computation import COINSTACPyNode, ComputationPhase


class PhaseLoadData(ComputationPhase):
    def compute(self):
        data = []
        for d in self.input['data']:
            if d % 2 == 0:
                data.append(d)
        return {'filtered_data': data}


class PhaseSaveResult(ComputationPhase):
    def compute(self):
        with open(f"{self.state['outputDirectory'] + os.sep + 'results.txt'}", 'w') as out:
            out.write(f"{self.input['aggregated_data']}")


local = COINSTACPyNode(mode='local', debug=True)
local.add_phase(PhaseLoadData)
local.add_phase(PhaseSaveResult)

Remote node pipeline:

from coinstac_computation import COINSTACPyNode, ComputationPhase, PhaseEndWithSuccess


class PhaseCollectMaxEvenData(ComputationPhase):
    def compute(self):
        data = []
        for site, site_vars in self.input.items():
            site_max = max(site_vars['filtered_data'])
            data.append(site_max)
        return {'aggregated_data': data}


remote = COINSTACPyNode(mode='remote', debug=True)
remote.add_phase(PhaseCollectMaxEvenData)
remote.add_phase(PhaseEndWithSuccess)

Entry point:

import coinstac

from local_pipeline import local
from remote_pipeline import remote

coinstac.start(local, remote)

Run:

cd examples/basic/
~/coinstac-computation/examples/basic/$ docker build -t base . && coinstac-simulator

---

Advanced use case example with multiple iterations where:

• Each sites cast a vote(positive vote if number is even) for multiple(default=51) times.
• Remote gathers the votes and returns the final voting result to all sites at the end.
• Sites save the final result.

Overview:

1. Specify when to end the iterative phase with a phase jump signal:

class PhaseSubmitVote(ComputationPhase):

    def _initialize(self):
        """This method runs only once"""
        self.cache['data_index'] = 0
        self.cache['data'] = []
        for line in open(self.state['baseDirectory'] + os.sep + self.input_args['data_source']).readlines():
            self.cache['data'].append(float(line.strip()))

    def compute(self):
        out = {
            'vote': self.cache['data'][self.cache['data_index']] % 2 == 0,
        }
        self.cache['data_index'] += 1
        
        """Send a jump to next phase signal"""
        out['jump_to_next'] = self.cache['data_index'] > len(self.cache['data']) - 1
        return out

2. Add the phase as multi-iterations:

local.add_phase(PhaseSubmitVote, multi_iterations=True)

---

Development notes:

• Make sure you have:
  • docker installed and running.
  • nodejs installed.
  • coinstac-simulator package installed. npm install --global coinstac-simulator
• Must set debug=False while deploying.
• Backward compatible to the older library(compspecVersion=1):
  • Add the following snippet at the end of local and remote pipeline scripts.

  if __name__ == "__main__":
      local.to_stdout()
  

  • Use version 1.0 compspec format.
  • Comment out line CMD ["python", "entry.py"] in the Dockerfile.
  • You can also use a remote debugger in pycharm as here.

Thanks!