Debugging Perl scripts without interactive debugger

By -

I've been tasked with understanding and debugging some legacy code written in Perl 5. The comments aren't great, and I have almost zero experience with the language (I'm a Python guy; some shell scripting experience). Basically, I need to understand it to the point where I can decide if it will be worth it to rewrite it in Python to match the rest of our code base and be more readable to those who aren't familiar with Perl's less obvious syntax (at least, to the uninitated...) or just leave it as is and do our best to make small changes as necessary despite having an incomplete understanding of what's going on.

Perl is being invoked to process some data from within a script in our organization's internal scripting language (which is used to interact with our proprietary hardware). The part written in the in the proprietary scripting language is similar to a shellscript in that every line sent to the interpreter will be written in the log, so while not as easy as debugging something like Python in a modern IDE, it's possible to figure out what's going on by checking the logs. But perl, as a programming language, only prints/logs what you tell it to. So as of right now, it's kind of a black box.

I looked at the Perl docs and saw that there is a command line option to launch the debugger -d, along with -Dtls to configure debugger behavior (those are the recommend options to "watch how perl executes your program"). But when I tried running that in the script, i got the following...warning? error?

Recompile perl with -DDEBUGGING to use -D switch (did you mean -d ?)

Because it's being called inside a proprietary-scripting langauge script, if this debugger is just an interactive shell, I don't think it will suit this purpose (because I can't send things to stdin while the proprietary-scripting langauge script is running). But if it's not interactive, adding a 2nd perl installation to the server for debugging wouldn't be out of the question, so if anyone has experience with this debugger mode, and options, I would appreciate some feedback about that.

I'm quite familiar with Python, so I know alot of tricks to log everything or to set up a debug environment to use the VS code debugger, but with Perl, I'm out of my comfort zone.

My question is: is there some sort of easy way (a flag or something) to call Perl in such a way where every command sent to the interpreter is written to the console/stdout/ or a logfile in the same way as a shell script? Or is there another good way to debug perl scripts (other than using the interactive debug shell)? Or do I have no better option than to take the time to go through this rather massive script and put print statements everywhere?

Thanks for reading a lengthy question.



Comments

Post a Comment

Popular posts from this blog

Today Walkin 14th-Sept

By -
Image
14th Sept 2017 ( GO Through all List) Read Walkin details properly , Try to call company before attending if possible !!! ==================================== 1. Myntra through fresherworld (Call Based , Venue shared to shortlisted candidates) _____________________________ 2. Magna : Hiring for Client Harman : C++
Read more

Spring Elasticsearch Operations

By -
Elasticsearch Operations Spring Data Elasticsearch uses two interfaces to define the operations that can be called against an Elasticsearch index. These are ElasticsearchOperations and ReactiveElasticsearchOperations. Whereas the first is used with the classic synchronous implementations, the second one uses reactive infrastructure. The default implementations of the interfaces offer: Read/Write mapping support for domain types. A rich query and criteria api. Resource management and Exception translation. ElasticsearchTemplate The ElasticsearchTemplate is an implementation of the ElasticsearchOperations interface using the Transport Client. @Configuration public class TransportClientConfig extends ElasticsearchConfigurationSupport {   @Bean   public Client elasticsearchClient() throws UnknownHostException {                      Settings settings = Settings.builder().put("cluster.name", "elasticsearch")....
Read more

Hibernate Search - Elasticsearch with JSON manipulation

By -
Elasticsearch with JSON manipulation Elasticsearch ships with many features. It is possible that at some point, one feature you need will not be exposed by the Search DSL. To work around such limitations, Hibernate Search provides ways to: Transform the HTTP request sent to Elasticsearch for search queries. Read the raw JSON of the HTTP response received from Elasticsearch for search queries. Direct changes to the HTTP request may conflict with Hibernate Search features and be supported differently by different versions of Elasticsearch. Similarly, the content of the HTTP response may change depending on the version of Elasticsearch, depending on which Hibernate Search features are used, and even depending on how Hibernate Search features are implemented. Thus, features relying on direct access to HTTP requests or responses cannot be guaranteed to continue to work when upgrading Hibernate Search, even for micro upgrades (x.y.z to x.y.(z+1)). Use this at your own risk....
Read more