How to define SOA services?

• In this blog entry I try to collect my experience defining SOA services. (This blog entry will be under heavy changes). Feel free to post me any comments.

If you build a service, keep always in mind that you have a lot of stakeholders in mind:

(1) service consumers
- which are interested in only the functionality they have to provide
- focued on a specific programm language (e.g. Java)
(2) architecture, which is mainly focused on
- reusability
- continuity
- versioning
- accessibility of services (repository, registry)
(3) service providers
- which are focused in reducing complexitiy
- which are focued on a specific programm language (e.g. Cobol)
(4) Business, interested in
- bussiness value
- continuity


(1)The Service consumer View
Focused on their particular problem

(2)The architecture view:
- Lego approach, composable services
- Versioning
- Lifecycle

(3)The architecture view:
- Reducing complexity. Reducing input and building constraints to reduce complexity of programming and testing

(4) Business
- The business is mainly interested into shareholder value

The goals on a timeline looks like this
(1) Service Consumers (goals are within project time)
(2) Service Producers (Services should survive different projects)
(3) Business (mid term goals)
There are a lot of conflicts:
(1) and (3): How to find a naming
(4)Architecture (long term gols)

convention which fullfill different programming approaches
(1 - 4) How to fullfill the different time scopes? --> Versioning,


Distinguish between
(a) Bulk-Services (File-Import)
(b) Messaging Services (e.g. Webservices)

(a) Bulk Services (Func. and non func. req)
- Define Character Format
- Define Output Format (Fixed-Length, Comma-Separated, ....)
- Define all attributes precise (especially years, currency, ...) e.g. DDMMYYYY, XXXX.YYYY and Currency ISO 4217
- Specify timezones for dates
- Define Periodicity (Exportdates)
- Availability
- Security Classification
- Response Time
- Size of the Export (e.g. 10 GB)
- Destination/Protocol (e.g. ftp://myFileserver)
- Logging
- When should service go in to Integration Test, Production, ...
- Versioning

(b) Messaging Services (Func. and non func. req)
- Availability
- Response Time
- Invocation Frequency
- Specify timezones for dates
- Define all attributes precise (especially years, currency, ...) e.g. DDMMYYYY, XXXX.YYYY and Currency ISO 4217
- Peak
- Loggin
- Caller Auth.
- Security Classification
- When should service go in to Integration Test, Production, ...
- Versioning


Versioning of the servicedefinition is crucual. Important is that you write every change, ore even better also the reason (and responsible) for the change in the servicedefinition or a separate document.

Scale up vs. Scale Out

See http://weblogs.java.net/blog/malcolmdavis/archive/2006/07/scale_up_vs_sca.html

Reliability vs. Availability

Reliability: measured by time between system failures
o Distributed system should be more reliable than single system
o 5 machines with .95 probability of being up. 1 - .05*5 probability of
being up.

􀀂 Availability: fraction of time the system is usable.
o Redundancy improves it
o Need to maintain consistency
o Need to be secure
o Need to tolerate failures: mask failures, recover from errors.

http://www.cis.upenn.edu/~lee/07cis505/Lec/lec-ch7a-consistency-v3.pdf

Calculate in Google

Try the following search terms:

(120000+1500)*500 byte -> megabyte
(120 000 + 1 500) * 500 gram -> kilogram

Move Itunes-library to external drive

Move Itunes library to external drive (German)

Other helpful links:
Recreate your itunes library

sed / grep /awk and other useful commands

Here i'll post useful commands using sed grep & awk for OSX:

sed "s/SEARCHTERM/RESULTTERM/" result.txt

Convert Uppercase to lowercase
cat test.txt | tr [:upper:] [:lower:]

More information:SED onenliners

Delete your desired files:
find / -name "*\.eml" -exec rm -f {} \;

Guidelines for developing an application in Ruby on Rails

Here I collect some guidelines how to develop in Ruby on Rails. Please feel free to comment on these guidelines. I would love to discuss them since I am quite new in Ruby on Rails

- Use an IDE (e.g. NetBeans)
- Use version control (e.g. SubVersion)
- Use the model to implement business logic
- The controller should be lean
- Don’t put business logic in to the view
- DRY: Use partials and helper-classes, …
- Use CSS for rendering your page
- Use migrations sequentially
- Consolidate migrations

Java vs. Ruby

Java vs. Ruby
Compare Java, Ruby and PHP according to different criterias
The Ruby vs. Java Experiment

Rails cheat sheet

As follows I show you some rails commands, which are pretty useful. Read also the following document, which summarize the most useful Rails-commands:
byOnRails-Cheatsheet-BlaineKendall.pdf

Find first Order in the table
o = Order.find(1)

Find by SQL
Use o.findbySQL

Assume an order has n protocols:

order.rb
class Order < ActiveRecord::Base
has_many :protocols

end

class Protocol < ActiveRecord::Base
belongs_to :order
end

script/console
pp = Protocol.find(1)
oo = Order.find(1)
oo.protocols << pp
oo.protocols

Iterate trough oder-array

arrayorder = Order.find(:all)

arrayorder.each do |order|
p order
end

Access the session
session[:user_id]

In the view:
< %=h Protocol.find(order.id).orderinit_date % >

Access to params:
< %= params['controller'] % >

Ruby structures

If/then/else

order.order_date != nil ? order.order_date.strftime(" %d.%m.%Y %I:%M"):""

Ror: Redirecting

Redirect the form to a non default route:

# POST /customer_profiles.xml
def create
....
respond_to do |format|
if @customer_profile.save
flash[:notice] = 'CustomerProfile was successfully created.'
format.html { redirect_to new_customer_path }
format.xml { render :xml => @customer_profile, :status => :created, :location => @customer_profile }
else
...
end
end
end

1:n relations in ROR

1. Generate a customer_profile which belongs to a customer

./script/generate scaffold customer_profile name:string customer_id:integer

2. Make migration:

rake db:migrate

3. In the model customer_prfoile.rb

class CustomerProfile < ActiveRecord::Base
belongs_to :customer
end

4. In the console you can test the 1:n relation (script/console):

>> customer = Customer.create(:name => "Dominik")
=> #
>> cprofile = CustomerProfile.create(:name => "myprofile")
=> #
>> cprofile.customer = customer
=> #
>> p cprofile.customer.name
"Dominik"
=> nil
>> p cprofile.customer
#
=> nil
>>

Ruby routes howto

http://localhost:3000/customers/32/client_profiles/new


in routes.rb:

map.resources :customers do |c|
c.resources :client_profiles
end

in client_profiles_controler.rb:

in method new:


# GET /client_profiles/new
# GET /client_profiles/new.xml
def new
@client_profile = ClientProfile.new
@client_profile.customer_id = params[:customer_id]
respond_to do |format|
....
end
end

in method create:

# POST /client_profiles
# POST /client_profiles.xml
def create
@client_profile = ClientProfile.new(params[:client_profile])
@client_profile.customer_id = params[:customer_id]
respond_to do |format|
if @client_profile.save
.....
end

Scaffolding types

-binary
-boolean
-date
-datetime
-decimal
-float
-integer
-primary_key
-string
-text
-time
-timestamp


See also: http://www.packtpub.com/article/Working-with-Rails-ActiveRecord-Migrations-Models-Scaffolding-and-Database-Completion

Usefull ruby commands

Create project with mysql:
rails bla --database=mysql

Create database:
In the Projectdirectory: "rake db:create:all"

Update tables:
In the Projectdirectory: "rake db:migrate"

Start Server:
In the Projectdirectory: "script/server"

Start documentation:
gem server -p 3333

Start console:
In the Projectdirectory: "script/console"

Scaffolding:
./script/generate scaffold person_profile name:string company:string organisation:string unit:string function:string role:string

After using command "rake db:migrate" you'll find the generated code here:
http://localhost:3000/profiles

Show all routes:
rake routes

Partials:
Comming soon

Migrations in Ruby:
1. Create migration: script/generate migration alter_client_profile
2. Alter migration, see example below:
class AlterClientProfile <>

3. rake db:migrate

New consistent database from migrations:
- rake db:drop
- rake db:create
- rake db:migrate

MySQL using terminal with OSX

Precondition:
Install MySQL-Binary from http://dev.mysql.com/downloads/mysql/5.0.html#macosx-dmg

Start Server:
/usr/local/mysql/bin/mysqld_safe

Start DB-Client:
/usr/local/mysql/bin/mysql -u root
- Use Database: use langodem_development
- show tables;
- Delete Database: drop database langodem_development


Create DB langodem:
/usr/local/mysql/bin/mysqladmin -u root create langodem

Connect to DB langodem:
./mysql -u root langodem

Find all running mysql-server instances
ps -ef | grep mysqld

Kill all mysql-server instances
killall -TERM mysqld

Set Path in OSX / Linux

In bash_login

export PATH=/usr/local/mysql-max-5.0.27-osx10.4-powerpc/

Work with SVN from terminal

Work with a svn project:
svn chk https://my_svn_server

svn update: "Update from SVN-Server"
svn add

Install Ruby on Rail in 5 steps (Mac)

1. Install Xcode
2. Install MacPorts
3. Install MySql-DB using command line tool ports: ports install mysql5 +server
4. Update Rails using command line tool gem: "sudo gem update"
5. sudo gem install daemons gem_plugin mongrel mongrel_cluster --include-dependencies
6. sudo gem install mysql

Definitions

TCO (Total cost of ownership) Gesamtheit der Kosten einer Investition, die über ihren kompletten Lebenszyklus hinweg anfallen

Routing unter OSX

Routingtabelle anzeigen

netstat -rn -f inet

Bsp:
Routing tables
Internet:
Destination Gateway Flags Refs Use Netif Expire
default 172.16.0.1 UGSc 19 6 en1
10/24 10.0.0.2 UGSc 0 0 en1

Route hinzufügen:
wotruba@mac:~$ sudo route add -net 10.0.0.0 10.0.0.2 255.255.255.0
add net 10.0.0.0: gateway 10.0.0.2


Routen löschen

route delete -net 10.0.0.0 10.0.0.2 255.255.255.0