5 ms·

How I Start: Erlang

221 points by kungfooguru 12y ago

glesica 12y ago
This is a really great project that could really make going from zero to "productive" with a new language so much quicker and more fun. I can't wait for Rust and Elixir to happen :)
- krat0sprakhar 12y ago
  +1 Exactly what was required. It's hard to find opinionated guides on the web for this sort of thing and can be sometimes overwhelming for someone just starting out. Great project! Is there a way I can subscribe for updates via email? Thanks a ton!
  - kungfooguru 12y ago
    Not currently. I've setup a twitter account where I'll post updates https://twitter.com/how_i_start https://twitter.com/how_i_start and you'll see updates here https://github.com/howistart/howistart https://github.com/howistart/howistart before they go live. Depending on how much this picks up I may expand to having an update subscription list. Python and Elixir are next up. Those will hopefully be out by the second week of July.
    - arthurcolle 12y ago
      Just curious, what do you use Erlang for? I can think of neural networks as a possible use case but I don't hear much in the way of that.
      - lostcolony 12y ago
        That case has been talked about a little bit. http://www.springer.com/computer/swe/book/978-1-4614-4462-6 http://www.springer.com/computer/swe/book/978-1-4614-4462-6
      - dozzie 12y ago
        Mostly for network services and sometimes for network clients.
      - kungfooguru 12y ago
        Personally? To just restrict it to professionally, I've worked a few places using Erlang. One for providing resource discovery to the rest of the internal systems, one for a financial matching engine and currently at Heroku for the routing layer and the logging layer(https://github.com/heroku/logplex https://github.com/heroku/logplex).
      - mononcqc 12y ago
        Author here. I've used it professionally as a trainer and course developer (teaching Erlang), in Real Time Bidding systems for advertisement, and I'm currently at Heroku, where we use it for the routing layer and part of the logging layer of the platform.
      - MCRed 12y ago
        Any time you need to do multiple things at once, erlang (or elixir) is often the best choice. EG: If you have a website and want to serve more than one request at at time. If you have multiple people chatting or sending mail, or instant messaging, or voice communicating, erlang is a good choice. If you have a search engine with many people searching, while spiders crawl the web, erlang is a good choice. The only "downside" to erlang is new syntax and that its "slower" on a given node. But this last one isn't really a downside-- you can scale a process to 20 nodes with erlang a whole lot better than, say, node.js or java or go. None of those really support concurrency properly (of the ones who even try.) This makes erlang unique. I think many engineers try to tell themselves that the JVM or node.js or Go can be concurrent, but they are really just making excuses for the fact that the erlang syntax is a bit of a hurdle for getting started. I'm fine with that- it makes a great hiring filter! If someones learned erlang, you know something that makes them better than most of the rest of the programmers out there who are happy to believe rationalizations that let them get away with not learning erlang. (And if you're not thinking about concurrency you're even further behind.)
        arms 12y ago
        I'm curious why you think Golang doesn't support concurrency properly.
        pessimizer 12y ago
        For comparisons between Go and Erlang, I've been passing this out lately: https://news.ycombinator.com/item?id=7277957 https://news.ycombinator.com/item?id=7277957 edit: the entire thread, not just the OP.
        MCRed 12y ago
        I know go is not concurrent. It doesn't even try.
        mononcqc 12y ago
        Go is concurrent, and so is clojure (as mentioned in another response of yours). I don't know what definition of concurrency you're running with, but all of those I heard of, they make it possible to have it there. Not necessarily at the same scale or through the same means, but they definitely make concurrency possible.
arms 12y ago
Very cool! I think detailed examples like this are much more conducive to getting a feel for a language when you're just starting out than the typical "sift through the official docs then build a Hello World example." I'm going to set aside some time to work through this (and then go through the official docs.) Kudos for the Simpson's references; that's one of my favorite episodes :) I look forward to more of these.
steveklabnik 12y ago
I wrote the second article, which is on Ruby: http://www.howistart.org/posts/ruby/1 http://www.howistart.org/posts/ruby/1 I'm psyched to see more articles here.
- mononcqc 12y ago
  Yeah, I'm eager to see the project get more lift and more tutorials with time.
lmb 12y ago
Thanks for the write up, especially the part on relx was enlightening. I've been toying with Erlang, and have three questions I have not been able to find good answers to. Maybe someone could elaborate? 1) How well does Erlang deal with multiple VMs on a single machine? Are there any upsides to using a single VM per machine? (So, run your own code along side a RabbitMQ instance for example, if that is even feasible.) 2) What is a good way to have run-time mutable configuration data? I was looking into Mnesia to store user / password combinations, but it seems a bit overkill. Ideally a solution that lets you add / remove config data from a running node on the fly. 3) How do you handle access control to the node, while preserving the distributed Erlang features? VPN all machines and then only listen on the private interface?
- mononcqc 12y ago
  1) It deals with it well. There's no issue running one or more nodes on a single host or machine. It's been done that way before SMP was made nicer a few years ago. The distribution mechanism is based on a name@host scheme so as long as the total pair is unique to a cluster, things are usually fine. Running one VM per machine has a few upsides: better resource handling (large binaries are shared on a heap rather than copied), copying within a VM is cheaper than serializing over the network, and so on. The downside is lower isolation. For this reason, people will tend to bundle a bunch of services together if they relate to the same general logical block of applications. You should definitely be able to find a way to run your Erlang code around with RabbitMQ (though that depends on their compilation process and assumptions as well). They'll keep them separate for operational purposes often: some code bases are less mature, require more ops, crash more often, and so on, or have more erratic behavior, and so isolation is welcome in these cases. 2) See http://www.erlang.org/doc/man/config.html http://www.erlang.org/doc/man/config.html, http://www.erlang.org/doc/man/app.html http://www.erlang.org/doc/man/app.html, and http://www.erlang.org/doc/apps/kernel/application.html http://www.erlang.org/doc/apps/kernel/application.html Erlang comes out of the box with a configuration mechanism, which you may or may not make mutable at your choice on a per-application basis. 3) That's one way to do it, yes. This one or equivalent ones (restricting network access, IP tables, etc.) are the most used ones as far as I know. Some mechanisms can also include running an SSH daemon on the node and only allowing people with the right credentials to connect to a node. There's one that ships with the Erlang/OTP distribution.
gargantuan 12y ago
BTW this is the author of Learn You Some Erlang for Great Good http://learnyousomeerlang.com/ http://learnyousomeerlang.com/ I just wanted to say that both this write-up and in the whole book you can see passion, and excitement for the topic. They say cliches like "work of love" but if anything that defines it I think. It is the little humorous bits, the additional "Don't Drink Too Much Koolaid" parts, the visuals. It is a fantastic resource. I think this post is a partially the response to "Why Cool Kids Don't Use Erlang" topic we discussed recently. There was a lot of "Too hard to get started" and I think Fred took the initiative and did something about it. That is great. Thank you Fred!
kriro 12y ago
The Erlang post is fantastic. Haven't read the Ruby one yet. Excellent idea for a site. Thanks a lot.
tomwilson 12y ago
Hey this is really nice. I tried to get into Erlang from reading Armstrongs book (Programming Erlang) and just couldn't grok it. I think the later chapters of that get a bit more 'concrete' and start making real things but I lost interest by that point. Reading this has made me want to try again, though.

221 points by kungfooguru 12y ago

This is a really great project that could really make going from zero to "productive" with a new language so much quicker and more fun. I can't wait for Rust and Elixir to happen :)

krat0sprakhar 12y ago
+1 Exactly what was required. It's hard to find opinionated guides on the web for this sort of thing and can be sometimes overwhelming for someone just starting out. Great project! Is there a way I can subscribe for updates via email? Thanks a ton!
- kungfooguru 12y ago
  Not currently. I've setup a twitter account where I'll post updates https://twitter.com/how_i_start https://twitter.com/how_i_start and you'll see updates here https://github.com/howistart/howistart https://github.com/howistart/howistart before they go live. Depending on how much this picks up I may expand to having an update subscription list. Python and Elixir are next up. Those will hopefully be out by the second week of July.
  - arthurcolle 12y ago
    Just curious, what do you use Erlang for? I can think of neural networks as a possible use case but I don't hear much in the way of that.
    - lostcolony 12y ago
      That case has been talked about a little bit. http://www.springer.com/computer/swe/book/978-1-4614-4462-6 http://www.springer.com/computer/swe/book/978-1-4614-4462-6
    - dozzie 12y ago
      Mostly for network services and sometimes for network clients.
    - kungfooguru 12y ago
      Personally? To just restrict it to professionally, I've worked a few places using Erlang. One for providing resource discovery to the rest of the internal systems, one for a financial matching engine and currently at Heroku for the routing layer and the logging layer(https://github.com/heroku/logplex https://github.com/heroku/logplex).
    - mononcqc 12y ago
      Author here. I've used it professionally as a trainer and course developer (teaching Erlang), in Real Time Bidding systems for advertisement, and I'm currently at Heroku, where we use it for the routing layer and part of the logging layer of the platform.
    - MCRed 12y ago
      Any time you need to do multiple things at once, erlang (or elixir) is often the best choice. EG: If you have a website and want to serve more than one request at at time. If you have multiple people chatting or sending mail, or instant messaging, or voice communicating, erlang is a good choice. If you have a search engine with many people searching, while spiders crawl the web, erlang is a good choice. The only "downside" to erlang is new syntax and that its "slower" on a given node. But this last one isn't really a downside-- you can scale a process to 20 nodes with erlang a whole lot better than, say, node.js or java or go. None of those really support concurrency properly (of the ones who even try.) This makes erlang unique. I think many engineers try to tell themselves that the JVM or node.js or Go can be concurrent, but they are really just making excuses for the fact that the erlang syntax is a bit of a hurdle for getting started. I'm fine with that- it makes a great hiring filter! If someones learned erlang, you know something that makes them better than most of the rest of the programmers out there who are happy to believe rationalizations that let them get away with not learning erlang. (And if you're not thinking about concurrency you're even further behind.)
      - arms 12y ago
        I'm curious why you think Golang doesn't support concurrency properly.
        pessimizer 12y ago
        For comparisons between Go and Erlang, I've been passing this out lately: https://news.ycombinator.com/item?id=7277957 https://news.ycombinator.com/item?id=7277957 edit: the entire thread, not just the OP.
        MCRed 12y ago
        I know go is not concurrent. It doesn't even try.
        mononcqc 12y ago
        Go is concurrent, and so is clojure (as mentioned in another response of yours). I don't know what definition of concurrency you're running with, but all of those I heard of, they make it possible to have it there. Not necessarily at the same scale or through the same means, but they definitely make concurrency possible.

arms 12y ago

Very cool! I think detailed examples like this are much more conducive to getting a feel for a language when you're just starting out than the typical "sift through the official docs then build a Hello World example." I'm going to set aside some time to work through this (and then go through the official docs.) Kudos for the Simpson's references; that's one of my favorite episodes :) I look forward to more of these.

steveklabnik 12y ago

I wrote the second article, which is on Ruby: http://www.howistart.org/posts/ruby/1 http://www.howistart.org/posts/ruby/1 I'm psyched to see more articles here.

mononcqc 12y ago
Yeah, I'm eager to see the project get more lift and more tutorials with time.

lmb 12y ago

Thanks for the write up, especially the part on relx was enlightening. I've been toying with Erlang, and have three questions I have not been able to find good answers to. Maybe someone could elaborate? 1) How well does Erlang deal with multiple VMs on a single machine? Are there any upsides to using a single VM per machine? (So, run your own code along side a RabbitMQ instance for example, if that is even feasible.) 2) What is a good way to have run-time mutable configuration data? I was looking into Mnesia to store user / password combinations, but it seems a bit overkill. Ideally a solution that lets you add / remove config data from a running node on the fly. 3) How do you handle access control to the node, while preserving the distributed Erlang features? VPN all machines and then only listen on the private interface?

mononcqc 12y ago
1) It deals with it well. There's no issue running one or more nodes on a single host or machine. It's been done that way before SMP was made nicer a few years ago. The distribution mechanism is based on a name@host scheme so as long as the total pair is unique to a cluster, things are usually fine. Running one VM per machine has a few upsides: better resource handling (large binaries are shared on a heap rather than copied), copying within a VM is cheaper than serializing over the network, and so on. The downside is lower isolation. For this reason, people will tend to bundle a bunch of services together if they relate to the same general logical block of applications. You should definitely be able to find a way to run your Erlang code around with RabbitMQ (though that depends on their compilation process and assumptions as well). They'll keep them separate for operational purposes often: some code bases are less mature, require more ops, crash more often, and so on, or have more erratic behavior, and so isolation is welcome in these cases. 2) See http://www.erlang.org/doc/man/config.html http://www.erlang.org/doc/man/config.html, http://www.erlang.org/doc/man/app.html http://www.erlang.org/doc/man/app.html, and http://www.erlang.org/doc/apps/kernel/application.html http://www.erlang.org/doc/apps/kernel/application.html Erlang comes out of the box with a configuration mechanism, which you may or may not make mutable at your choice on a per-application basis. 3) That's one way to do it, yes. This one or equivalent ones (restricting network access, IP tables, etc.) are the most used ones as far as I know. Some mechanisms can also include running an SSH daemon on the node and only allowing people with the right credentials to connect to a node. There's one that ships with the Erlang/OTP distribution.

gargantuan 12y ago

BTW this is the author of Learn You Some Erlang for Great Good http://learnyousomeerlang.com/ http://learnyousomeerlang.com/ I just wanted to say that both this write-up and in the whole book you can see passion, and excitement for the topic. They say cliches like "work of love" but if anything that defines it I think. It is the little humorous bits, the additional "Don't Drink Too Much Koolaid" parts, the visuals. It is a fantastic resource. I think this post is a partially the response to "Why Cool Kids Don't Use Erlang" topic we discussed recently. There was a lot of "Too hard to get started" and I think Fred took the initiative and did something about it. That is great. Thank you Fred!

kriro 12y ago

The Erlang post is fantastic. Haven't read the Ruby one yet. Excellent idea for a site. Thanks a lot.

tomwilson 12y ago

Hey this is really nice. I tried to get into Erlang from reading Armstrongs book (Programming Erlang) and just couldn't grok it. I think the later chapters of that get a bit more 'concrete' and start making real things but I lost interest by that point. Reading this has made me want to try again, though.