IronSavior

Xen Dom0 on Debian Stretch

Version 2018-01-17: Erik Elmore erik@elmore.io

Install Dom0 System

Use the conventional Debian installer to install the base system. Disk layout:

• 256M boot ext4. Needs to be big enough for all kernel versions and modules for guests
• Rest of the disk to LVM2. Create logical volumes for:
  • root ext4 (8G-16G)
  • swap (optional, whatever size you like)

IronSavior

# Conway's Game of Life via Python coroutines
# Inspired by https://effectivepython.com/2015/03/10/consider-coroutines-to-run-many-functions-concurrently/

from enum import Enum
from collections import namedtuple
from itertools import islice, count, product, chain, repeat, accumulate, starmap
from functools import partial, lru_cache
from time import sleep
import operator as op

IronSavior

const {Readable, Writable} = require('stream');
const PRIVATE = Symbol('private state accessor');

// Writable stream that routes each chunk through one of its output streams as determined by a user-supplied fdunction.
//
// An output stream is dynamically created whenver the channel selector function returns a new channel ID. The channel
// IDs may be any value which can function as a Map's key. Listeners to the "channel" event will receive a new Readable
// channel output stream when a new channel is created.
//
// Please note that this stream respects backpressure signaled by its outputs. This means that the overall throughput

IronSavior

"use strict";
const {Transform} = require('readable-stream');
const PRIVATE = Symbol('ConcurrentTransform private state');
const NOOP_TRANSFORM = (chunk, _, done) => done(null, chunk);
const NOOP_FLUSH = done => done();

// Transform stream which processes chunks with limited (or unlimited) concurrency
class ConcurrentTransform extends Transform {
  // @param opts {Object} Stream options. Set concurrency limit with "concurrent" (default concurrency: 1)
  constructor( opts = {} ){

IronSavior

const error_policy = require('./error-policy');

// EventEmitter example
const {Readable} = require('stream');
class MyReadable extends Readable {
  constructor(){
    super(...arguments);
    this.policy = error_policy(e => this.emit('error', e));
  }

IronSavior

"use strict";
// Make predicate funtions more convenient.
// Works like Ruby's Symbol#to_proc, which is usually called with the unary & operator and a Symbol literal:
//   (ruby) %w[one two three].map(&:upcase)   # returns ["ONE", "TWO", "THREE"]
//   (js)   ['one', 'two', 'three'].map(toFn('toUpperCase'));  // returns ["ONE", "TWO", "THREE"]
//   (js)   ['one', 'two', 'three'].map(toFn`toUpperCase`);    // same as above, but called via tagged string literal
// @param name {String} Name of method
// @param ...bound_args Arguments to bind NOTE: Args cannot be bound when calling as a tagged-template
// @return {Function} Function to call named method with bound args on any object given at time of invocation
module.exports = function toFn( name, ...bound_args ){

IronSavior

const lambda_handler = require('lambda-handler');

exports.handler = lambda_handler(( event, ctx, done ) => {
  // This will log a handled error to CloudWatch and return the error to AWS Lambda
  throw 'BOOM!';
});

IronSavior

require 'set'

# Invokes the block, passing in all or some of the input. If the block throws, the block will be invoked
# repeatedly for a progressively smaller subset of the batch until all elements are either processed or
# failed. Elements contained in sub-batches which succeed are never re-tried. Returns two Arrays, the first
# contains all items which succeeded and the second contains all elements which failed.
#
# This can be useful when a batch API will throw when it receies one or more malformed items, but doesn't
# tell you which input items were at fault.
#

IronSavior

use std::io::{self, Read, BufRead};
use std::cmp;
use std::fmt::{self, Write};

const HR_BYTES_PER_LINE: usize = 16;

struct HexReader<T> {
    inner: T,
    buf: String,
    buf_pos: usize,

IronSavior

module Tracing
  def trace_message( msg = yield )
    level = String(__callee__).upcase
    puts ' ** [%s] %s: %s' % [level, self.class, msg]
  end
  %i[debug info warn error].each{ |m| alias_method m, :trace_message }
end