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# Auger | ||
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The Auger library implements a ruby DSL for describing tests to be run | ||
against remote applications on multiple servers. The gem includes | ||
'aug', a multi-process command-line client. | ||
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The primary goal of Auger is test-driven operations: unit testing for | ||
application admins. The library can also be used as a framework for | ||
implmenting automated tests. | ||
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These are the sorts of questions auger can answer: | ||
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* is port :80 on my application webservers open? does /index.html | ||
contain a response tag that we know should be served from a given | ||
backend data source? | ||
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* is redis running? is it configured as a master? a slave? | ||
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* is elasticsearch responding on all my hosts it should be? what's | ||
the cluster state? do I have the number of data nodes responding | ||
that we're supposed to have? | ||
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Clearly a lot of this information includes things you should be | ||
graphing. What auger wants to do is give you a quick overview | ||
of current status: green == good, red == ruh roh! | ||
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## What's it look like? | ||
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![Auger Screenshot](https://raw.github.com/brewster/assets/master/img/auger/cmdline_screenshot.png "Auger Command Line") | ||
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## Plugins | ||
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Specific protocols are implemented using plugins, which are designed | ||
to be easy to write wrappers on existing gems. Auger currently includes | ||
the following plugins: | ||
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* socket - test whether a port is open | ||
* telnet - send arbitrary commands to a port using `net/telnet` | ||
* http - http and https requests using `net/http` | ||
* redis - query redis db info, keys, etc | ||
* dns - domain and query requests for testing a DNS server | ||
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## Installation | ||
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gem install auger | ||
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### If you want to run the latest source: | ||
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git clone git@github.com/brewster/auger | ||
cd auger; bundle install && rake install | ||
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## Command-line client usage | ||
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`aug -h` will print usage details. | ||
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Sample configs are included in `auger/cfg/examples` (if installed as a | ||
gem, look in `$GEM_HOME/gems/auger-x.x.x/cfg/examples`). Use them as a | ||
basis to write your own tests, which auger can find in one of three ways: | ||
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* in the directory `auger/cfg` | ||
* from the config load path defined in environment variable `AUGER_CFG`. | ||
e.g. `AUGER_CFG=~/aug_cfg/prod:~/aug_cfg/staging` | ||
* using a relative path | ||
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Reference config files using `aug foo`, to find `foo.rb` in | ||
`auger/cfg` or `AUGER_CFG` path, or `aug path/to/foo.rb` to find it directly. | ||
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`aug -l` will print available config files in `AUGER_CFG` path. | ||
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### Example 1 - testing a webserver response | ||
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```ruby | ||
project "Front-end Web Servers" do | ||
server "web-fe-[01-02]" | ||
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http 8000 do | ||
get '/' do | ||
test 'status code is 200' do |response| | ||
response.code == '200' | ||
end | ||
end | ||
end | ||
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end | ||
``` | ||
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The `project` command takes a project description, and a block containing multiple | ||
tests to be run together for that project. | ||
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`server` lists hosts that should be tested. It may be called multiple times, and | ||
also parses host range expressions using the HostRange gem. | ||
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`http` is an example of a connection, it takes an argument with the port to | ||
connect, and a block containing multiple requests to make. | ||
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`get` is a request, in this case an HTTP GET to the provided url, and takes a block | ||
with multiple tests to run on the response. Plugins can return any object from | ||
a request, in the case of `http` the response is an HTTP::Reponse object. | ||
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`test` describes a test to run on the provided response; it takes a description, | ||
and the response is passed to a block. The result of executing the block is | ||
presented as the result of this test (in this case true or false). | ||
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For better control over the result, it is possible to construct and | ||
return an Auger::Result object, with an outcome (string to be | ||
printed) and a boolean status (which aug client will use to print | ||
the result in green or red), for example: | ||
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```ruby | ||
test 'http status code' do |response| | ||
Result(response.code, response.code == '200') | ||
end | ||
``` | ||
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will always show the code, in green if 200, red otherwise. | ||
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Save the config to a file `fe_web` and run with the `aug` command: | ||
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$ aug ./fe_web | ||
[web-fe-01] | ||
status code is 200 ✓ | ||
[web-fe-02] | ||
status code is 200 ✓ | ||
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### Example 2 - adding more tests | ||
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Let's extend our example to be more interesting. | ||
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```ruby | ||
project "Front-end Web Servers" do | ||
server 'web-fe-[01-02]', :web | ||
server 'www.mydomain.com', :vip, :port => 80 | ||
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socket 8000 do | ||
roles :web | ||
open? do | ||
test "port 8000 is open?" | ||
end | ||
end | ||
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http 8000 do | ||
roles :web, :vip | ||
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get '/' do | ||
test 'status code is 200' do |response| | ||
response.code == '200' | ||
end | ||
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test 'document title' do |response| | ||
response.body.match /<title>([\w\s]+)<\/title>/ | ||
end | ||
end | ||
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get '/image.png' do | ||
header 'user-agent: Auger Test' | ||
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test 'image.png has correct content-type' do |respose| | ||
response['Content-Type'] == 'image/png' | ||
end | ||
end | ||
end | ||
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end | ||
``` | ||
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Servers can have roles attached to them, in this case `:web` and | ||
`:vip`. By default a connection will be run for all servers, but the | ||
`roles` command allows connections to be limited to the given roles. | ||
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Servers can also have a hash of options, which will override | ||
the matching connection options for just that server. In this case | ||
we want to connect to port 80 on the vip rather than 8000. | ||
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Server names may be given as strings (which will be parsed by HostRange), | ||
as arrays (or expressions returning arrays), or as a block returning | ||
an array. All arrays will be flattened. Hence the following are all | ||
equivalent: | ||
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```ruby | ||
server "foo1", "foo2", "foo3" | ||
server "foo[1-3]" | ||
server HostRange.parse("foo[1-3]") | ||
server [ "foo1", "foo2", "foo3" ] | ||
server do | ||
%w{ foo1 foo2 foo3 } | ||
end | ||
``` | ||
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The `header` command demonstrates setting options for a request, | ||
in this case setting an http request header. | ||
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The `socket` command creates a connection to the given port, and | ||
`open?` returns true if the port is open. We just apply this to | ||
the real web servers and not the vip. | ||
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The document title test demonstrates how to extract and return a regex | ||
match. Tests can return almost any object (including Exceptions), and | ||
auger will try to display the result using the `.to_s` method. Ruby's | ||
MatchData object, however, gets special treatment. If the MatchData | ||
has captures (captured using parentheses in the regex) they will be | ||
displayed, as in this case. If no captures, the MatchData will be | ||
treated as a boolean. The `aug` cmdline client displays booleans with | ||
a checkmark or an 'x'. | ||
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### Example 3 - testing ElasticSearch | ||
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```ruby | ||
require 'json' | ||
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project "Elasticsearch" do | ||
server 'prod-es-[01-04]' | ||
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http 9200 do | ||
get "/_cluster/health" do | ||
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# this runs after request returns, but before tests | ||
# use it to munge response body from json string into a hash | ||
before_tests do |r| | ||
r.body = JSON.parse(r.body) | ||
end | ||
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test "Status 200" do |r| | ||
r.code == '200' | ||
end | ||
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# Now we'll define an array called stats, which contains all the keys we | ||
# want to retrieve values from in our /_cluster/health output. In this | ||
# case, we'll just return the body of the response, as it's relatively | ||
# small. You can of course parse this however you'd like for this or | ||
# other cases. | ||
stats = %w[ | ||
cluster_name | ||
status | ||
timed_out | ||
number_of_nodes | ||
number_of_data_nodes | ||
active_primary_shards | ||
active_shards | ||
relocating_shards | ||
initializing_shards | ||
unassigned_shards | ||
] | ||
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stats.each do |stat| | ||
test "#{stat}" do |r| | ||
r.body[stat] | ||
end | ||
end | ||
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# I've discovered that a typical fail case with elasticsearch is | ||
# that on occassion, nodes will come up and not join the cluster | ||
# This is an easy way to see if the number of nodes that the host | ||
# actually sees (actual_data_nodes) matches what we're | ||
# expecting (expected_data_nodes). | ||
# TODO: dynamically update expected_data_nodes based on defined hosts: | ||
test "Expected vs Actual Nodes" do |r| | ||
r.body['number_of_data_nodes'] == 8 | ||
end | ||
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end | ||
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end | ||
``` | ||
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## Writing plugins | ||
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Let's look at a simplified http plugin. | ||
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```ruby | ||
require "net/http" | ||
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module Auger | ||
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class Project | ||
def http(port = 80, &block) | ||
@connections << Http.load(port, &block) | ||
end | ||
end | ||
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class Http < Auger::Connection | ||
def open(host, options) | ||
http = Net::HTTP.new(host, options[:port]) | ||
http.start | ||
http | ||
end | ||
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def close(http) | ||
http.finish | ||
end | ||
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def get(url, &block) | ||
@requests << Auger::HttpRequest.load(url, &block) | ||
end | ||
end | ||
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class HttpRequest < Auger::Request | ||
def run(http) | ||
get = Net::HTTP::Get.new(@arg) | ||
http.request(get) | ||
end | ||
end | ||
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end | ||
``` | ||
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First, we add the `http` method to the Project class. This simply causes | ||
the 'http' command to add a connection of class Http to the project's | ||
list of connections. | ||
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Next, we define the Http connection class by sub-classing `Auger::Connection`. | ||
A connection class needs to define `open` and `close` methods, which will | ||
create and destroy a connection object (in this case a Net::HTTP object). | ||
`open` takes a hostname and the connection @options hash, and returns an | ||
instance of the relevant request object. | ||
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## Command Line Auto-completion for aug tool | ||
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BASH completion (with file completion and a rolling cache, if you're incredibly impatient like me): | ||
```bash | ||
_augcomp() | ||
{ | ||
count=100 | ||
augcache="/tmp/.aug_cache" | ||
augcounter="/tmp/.aug_counter" | ||
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# if the cache or the counter don't exist, create | ||
if [ ! -f "$augcache" ] || [ ! -f "$augcounter" ] | ||
then | ||
aug -l >$augcache && echo 0 >$augcounter | ||
else | ||
# if the counter reaches $count, re-generate the complete list | ||
if [ $(cat "$augcounter") -eq "$count" ] | ||
then | ||
aug -l >$augcache && echo 0 >$augcounter | ||
# if the counter hasn't reached $count, increment it | ||
else | ||
expr $(cat $augcounter) + 1 >$augcounter | ||
fi | ||
fi | ||
augcfgs=$(cat "$augcache" | xargs) | ||
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word=${COMP_WORDS[COMP_CWORD]} | ||
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_compopt_o_filenames | ||
COMPREPLY=($(compgen -f -W "$augcfgs" -- "${word}")) | ||
} | ||
complete -F _augcomp aug | ||
``` | ||
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ZSH completion: | ||
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_augprojects () { _files; compadd $(aug -l) } | ||
compdef _augprojects aug | ||
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## Augweb | ||
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Auger now has a simple web interface, | ||
[augweb](http://github.com/brewster/augweb), showing tabulated test | ||
results and charts of response times. | ||
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## Ports | ||
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[Augen](https://github.com/simoneb/augen) is an ongoing attempt to | ||
port auger to .NET. | ||
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## Pull Requests | ||
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Yes please. | ||
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New plugins and general bug fixes, updates, etc are all welcome. | ||
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Generally, we'd prefer you do the following to submit a pull: | ||
* fork | ||
* create a local topic branch | ||
* make your changes and push | ||
* submit your pull request | ||
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## License | ||
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Auger is distributed under the MIT license. See the attached LICENSE | ||
file for all the sordid details. | ||
## This repository has moved! | ||
* The authoritative copy can be found at: [rlister/auger](https://github.com/rlister/auger) |