Eric Avdey eiri

$ erl -noshell -eval 'erlang:display(erlang:system_info(system_version))' -eval 'init:stop()'
"Erlang/OTP 20 [erts-9.1.1] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]\n"

Vagrant setup for go dev

Overview

Linux: Debian Stretch
Provisioning: Ansible
Go: 1.9.1

Pre-requirements

VirtualBox: 5.1.28
Vagrant: 2.0.0

Edit CouchDB design document with curl

create new database

$ curl -X PUT http://localhost:5984/koi
{"ok":true}

create a single document

$ curl -X POST http://localhost:5984/koi -d '{"name":"alice","age":25}' -H'Content-Type:application/json'

Short primer on using attachment in CouchDB

In db "koi" create a doc named "tesla"

$ http put :5984/koi/tesla name=alice
{
    "id": "tesla", 
    "ok": true, 
    "rev": "1-2350796167caec1f6ba70e9145a9e102"

REST Cheatshit

REST to CRUD

POST - create
GET - read
PUT - update (replace)
PATCH - update (partial)
DELETE - delete
HEAD - verify

Working with local documents in CouchDB

Create

No such document

$ http :5984/koi/_local/020
{
    "error": "not_found", 
    "reason": "missing"
}

Start dev cluster:

$ ./dev/run --admin eiri:eiri
[ * ] Setup environment ... ok
[ * ] Ensure CouchDB is built ... ok
[ * ] Prepare configuration files ... ok
[ * ] Start node node1 ... ok
[ * ] Start node node2 ... ok
[ * ] Start node node3 ... ok
[ * ] Check node at http://127.0.0.1:15984/ ... ok

CouchDB view compaction

Sequence diagram of CouchDB 2.0 compaction

Diaglam of calls during view compaction in CouchDB 2.0. Some steps omitted to simplify things.

View: http://bl.ocks.org/eiri/c436914e4115651c78d1eef9de68c70e

Example of using js-sequence diagram in gist

How to share

Bl.ocks is a nice way for sharing code examples hosted on gitHub gist. All that needed is just to replace “gist.github.com” with “bl.ocks.org” in the URL, e.g. http://bl.ocks.org/eiri/073a9e12f8246927ef997bf6f3ab5561

Sequence file loading

Sequence is just a simple text file loaded with syncronious ajax call.

	- name: activate erlang 17.5 on login
	lineinfile:
	dest: /home/vagrant/.bashrc
	line: "{{item.line}}"
	insertafter: "{{item.insertafter}}"
	state: present
	with_items:
	- insertafter: "#alias l='ls -CF'"
	line: '# activate erlang 17.5'
	- insertafter: '# activate erlang 17.5'