indyarocks

FROM rails:4.2.3

MAINTAINER Renato Filho <renatosousafilho@gmail.com>

ENV HOME /home/app
ENV RAILS_ENV development

RUN useradd -m -s /bin/bash app

RUN gem install -N bundler

indyarocks

Docker

Files and Folders.

|
|\_ app
|...
|\_ docker
| |

indyarocks

Credit: Based on asukakenji

Modified: To check for all version of Go in go[0-9].[0-9][0-9].[0-9] pattern

Go (Golang) Standard Library Interfaces (Selected)

This is not an exhaustive list of all interfaces in Go's standard library. I only list those I think are important. Interfaces defined in frequently used packages (like io, fmt) are included. Interfaces that have significant importance are also included.

indyarocks

%Q, %q, %W, %w, %x, %r, %s, %i

Perl-inspired notation to quote strings: by using % (percent character) and specifying a delimiting character.

Any single non-alpha-numeric character can be used as the delimiter, %[including these], %?or these?, %~or even these things~.

Strings

% or %Q

indyarocks

Streaming processing services:
1. https://medium.com/@chandanbaranwal/spark-streaming-vs-flink-vs-storm-vs-kafka-streams-vs-samza-choose-your-stream-processing-91ea3f04675b

Consistent Hashing:
Article - https://medium.com/@sent0hil/consistent-hashing-a-guide-go-implementation-fe3421ac3e8f
Golang - https://github.com/indyarocks/consistent

indyarocks

Rails 7 new features. Before and After

• Add ComparisonValidator
• PostgreSQL generated columns
• PostgreSQL custom enum types
• Add tracking of belongs_to association
• association_previously_changed? method
• Add invert_where method
• Add associated method
• Add missing method
• Active Record Encryption

indyarocks

# have_attr_reader matcher for attr_reader
RSpec::Matchers.define :have_attr_reader do |field|
  match do |object_instance|
    object_instance.respond_to?(field)
  end

  failure_message do |object_instance|
    "expected attr_reader for #{field} on #{object_instance}"
  end

indyarocks

1. Change your database RDS instance security group to allow your machine to access it.
   • Add your ip to the security group to acces the instance via Postgres.
2. Make a copy of the database using pg_dump
   • $ pg_dump -h <public dns> -U <my username> -f <name of dump file .sql> <name of my database>
   • you will be asked for postgressql password.
   • a dump file(.sql) will be created
3. Restore that dump file to your local database.
   • but you might need to drop the database and create it first
   • $ psql -U <postgresql username> -d <database name> -f <dump file that you want to restore>

• the database is restored

indyarocks

127.0.0.1:6379> ZADD class1:math 98 Tithi 50 Raju 80 Andrew # Create a new class 1 math score SET. 
(integer) 3                                                 # Add three members with their respective scores
127.0.0.1:6379> ZRANGEBYSCORE class1:math 0 10   # Fetch students scored between 0 to 10. No Student scored between 0 to 10
(empty list or set)
127.0.0.1:6379> ZRANGEBYSCORE class1:math 0 60  # Fetch students scored between 0 to 60. Raju
1) "Raju"
127.0.0.1:6379> ZRANGEBYSCORE class1:math 0 60  WITHSCORES # Fetch students with scores who scored between 0 to 60. Raju
1) "Raju"
2) "50"
127.0.0.1:6379> ZRANGE class1:math 0 10  WITHSCORES # Fetch students from ZSET class1:math with position 0 to 10. 

indyarocks

127.0.0.1:6379> HSET my_hash key1 1 # Initializes a HASH my_hash with key-value key1: 1
(integer) 1
127.0.0.1:6379> HSET my_hash key2 value2 # Sets another key-value pair key2: value2 in my_hash
(integer) 1
127.0.0.1:6379> HGET my_hash key1 # GET the data for key1 in my_hash
"1"
127.0.0.1:6379> HGET my_hash key2 # GET the data for key2 in my_hash
"value2"
127.0.0.1:6379> HGETALL my_hash # GET the complete data in my_hash
1) "key1"