jlafon

An introduction to DynamoDB

DynamoDB is a powerful, fully managed, low latency, NoSQL database service provided by Amazon. DynamoDB allows you to pay for dedicated throughput, with predictable performance for "any level of request traffic". Scalability is handled for you, and data is replicated across multiple availability zones automatically. Amazon handles all of the pain points associated with managing a distributed datastore for you, including replication, load balancing, provisioning, and backups. All that is left is for you to take your data, and its access patterns, and make it work in the denormalized world of NoSQL.

Modeling your data

The single most important part of using DynamoDB begins before you ever put data into it: designing the table(s) and keys. Keys (Amazon calls them primary keys) can be composed of one attribute, called a hash key, or a compound key called the hash and range key. The key is used to uniquely identify an item in a table. The choice of the primary key is particularl

jlafon

import random
from pynamodb.models import Model
from pynamodb.attributes import UnicodeAttribute, NumberAttribute
from pynamodb.indexes import LocalSecondaryIndex, AllProjection


class ViewIndex(LocalSecondaryIndex):
    """
    This class represents a local secondary index
    """

jlafon

from pynamodb.models import Model
from pynamodb.attributes import UnicodeAttribute


def make_id():
    return somerandomid

class Thread(Model):
    table_name = 'Thread'
    forum_name = UnicodeAttribute(hash_key=True)

jlafon

from __future__ import print_function
import logging
from pynamodb.models import Model
from pynamodb.attributes import (UnicodeAttribute)

logging.basicConfig()
log = logging.getLogger("")
log.setLevel(logging.DEBUG)
log.propagate = True

jlafon

Keybase proof

I hereby claim:

• I am jlafon on github.
• I am jlafon (https://keybase.io/jlafon) on keybase.
• I have a public key whose fingerprint is 852D 73C3 9990 1540 B38C DE44 8D70 F113 3806 3D18

To claim this, I am signing this object:

jlafon

[alias]
  # View abbreviated SHA, description, and history graph of the latest 20 commits
  l = log --pretty=oneline -n 20 --graph --abbrev-commit
  
  # View the current working tree status using the short format
  s = status -s
  
  # Show the diff between the latest commit and the current state
  d = !"git diff-index --quiet HEAD -- || clear; git --no-pager diff --patch-with-stat"
  

jlafon

from pynamodb.models import Model
from pynamodb.attributes import (
    UnicodeAttribute, NumberAttribute
)


class Thread(Model):
    table_name = "Thread"
    forum_name = UnicodeAttribute(hash_key=True)
    subject = UnicodeAttribute(range_key=True)

jlafon

Sender Receiver Bytes
0 0 0
0 1 1416764092
0 2 4098253320
0 3 2106916386
0 4 1262617412
0 5 1059002706
0 6 891019678
0 7 719843912
0 8 794784178

jlafon

Here is an example .gitmodules that will cause a segmentation fault:

[submodule "foo-module"]
    path
    url = http://host/repo.git
$ git status
Segmentation fault (core dumped)

This occurs because in the function parse_submodule_config_option, the
variable 'value' is assumed not to be null, and when passed as an

jlafon

$ mkvirtualenv elasticluster
(elasticluster) $ pip install elasticluster
...
(elasticluster) $ elasticluster list
WARNING:gc3.elasticluster:Deploying default configuration file to /Users/jlafon/.elasticluster/config.
Traceback (most recent call last):
  File "/Users/jlafon/.virtualenv/elasticluster/bin/elasticluster", line 8, in <module>
    load_entry_point('elasticluster==1.0.0', 'console_scripts', 'elasticluster')()
  File "/Users/jlafon/.virtualenv/elasticluster/lib/python2.7/site-packages/elasticluster/main.py", line 152, in main
    app.run()