Flat file vs database

Flat file

• Easy to set up, only have to consider local file permissions
• Easy to implement in an ad-hoc way, ideal for a prototype
• Plain text for very simple things like a list
• JSON/YAML/Perl for complex data structures
• Doesn't work when the app is load balanced across multiple servers
• Not automatically backed up
• Amazon S3 is relatively expensive
• Have to make your own model

Database

• Requires up-front schema design - more work, but forces you to consider design of data 
• You can put business logic in the ResultSet models
• Requires an instance to be provisioned
• Easy cross-referencing of data
• Works when the app is load balanced across multiple servers
• Backup-as-a-service (i.e. replication)
• Amazon RDS is cheaper than S3
• Get the model for free with ORM

Conclusion

For production services that have redundancy (load balanced), always use a database unless the overhead of setting one up for the first time is considered too high for the business.

Use Data::Compare to compare data outside a test

Need to compare data outside of a test, without generating "ok" / "not ok" TAP output? Use Data::Compare.

Open source code review tools comparison

Options I'm familiar with for Subversion:

• ReviewBoard - good, but fiddly to install. Emails all your comments in a batch when you're ready.
• Atlassian Stash - okay but generates one email per comment. No, that's been fixed!
• Kallithea - looks good, not tried.

Perl modules for SOAP

Options/notes:

• W3C::Soap - not good
• SOAP::Lite - not as good as XML::Compile
• XML::Compile - recommended
• XML::Compile::SOAP
• XML::Compile::SOAP11
• XML::Compile::WSDL11

...but generally SOAP isn't much fun.
Expect the WSDL to be wrong, you may need to store a "fixed" copy locally.

How to install ruby, rake, rubygems

https://www.ruby-lang.org/en/documentation/installation/

For ruby, tried:

• https://rvm.io/ - wouldn't work on my Suse setup
• https://github.com/sstephenson/rbenv#readme - worked on Suse. Promising, I like.
• https://github.com/sstephenson/ruby-build#readme - doesn't work

For rubygems, tried:

• https://rubygems.org/pages/download - worked

For rake:

• It comes with ruby

Now learn Ruby:
https://github.com/neo/ruby_koans

Search engines

List:

• HP Autonomy IDOL
• Google search appliance
• Solr / Lucene
• Atlassian Jira/Wiki search
• Knowledge bases (untested):
• http://www.helpgizmo.com/
• https://www.zendesk.com/knowledge-base
• http://www.knowledgebase-script.com/
• http://www.spiceworks.com/free-it-knowledge-base-software/

Perl Tests: Better output when comparison fails

use Test::More;
use Test::Differences;

is_deeply($actual, $expected, 'foo') or eq_or_diff($actual, $expected, 'oof');

or

is_deeply($actual, $expected, 'foo') or diag explain $actual;

Case sensitive MySQL column

Make a case sensitive varchar column:

CREATE TABLE `page_dm` (
`url` varchar(500) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL,
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

http://dev.mysql.com/doc/refman/5.0/en/case-sensitivity.html
http://dev.mysql.com/doc/refman/5.0/en/create-table.html

Perl test comparison methods

Test::More

use Test::More tests => 23;
# or
use Test::More qw(no_plan); 

ok($got eq $expected, $test_name);

like ($got, qr/expected/, $test_name);

is_deeply($got_complex_structure, $expected_complex_structure, $test_name);

Test::Differences

Compare data structures

eq_or_diff $got, $expected, "description"

Test::Lazy

No descriptions required

# Will evaluate the code and check it:
try('qw/a/' => eq => 'a');

# Don't evaluate, but still compare:
check(1 => is => 1);

Bash variable comparisons

...bash logic...

Note that integer and string comparison use a different set of operators.

integer comparison

-eq

is equal to

if [ "$a" -eq "$b" ]

-ne

is not equal to

if [ "$a" -ne "$b" ]

-gt

is greater than

if [ "$a" -gt "$b" ]

-ge

is greater than or equal to

if [ "$a" -ge "$b" ]

-lt

is less than

if [ "$a" -lt "$b" ]

-le

is less than or equal to

if [ "$a" -le "$b" ]

<

is less than (within double parentheses)

(("$a" < "$b"))

<=

is less than or equal to (within double parentheses)

(("$a" <= "$b"))

>

is greater than (within double parentheses)

(("$a" > "$b"))

>=

is greater than or equal to (within double parentheses)

(("$a" >= "$b"))

string comparison

=

is equal to

if [ "$a" = "$b" ]

==

is equal to

if [ "$a" == "$b" ]

This is a synonym for =.

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