gar1t / e2

Project that aims to simplify Erlang/OTP development and improve developer productivity

e2

e2 is a small Erlang library that helps you write better software in less time.

• Erlang is hands down the best general purpose language for writing quality software using fewer lines of code
• It’s not always obvious how to use Erlang to do this
• e2 makes it obvious!

If you think the first point is controversial, take a closer look at e2 before settling the issue in your mind. It may take some time and effort before all the pieces come together – but isn’t the promise tempting!

Get started here:

http://e2project.org

e2's Issues

Something seems weird

Hi,

disclaimer: I'm a newbie, so not on the head (nor the balls !)

Trying to understand how the architecture works, I added io:format(…) almost everywhere in the tutorial example; the object of my question is about a part that seems to be static (always the same PID), thus, might be a choke point.

When clients call, they're requests are processed by different PID, so I understand it as parallelism, but one part stays "static" (I also made tests with a lot of clients, with the same result) - so, my question is:
is it because the PID is fast released an re-used immediately ?
or, if it means all requests pass through the same PID, it is a choke point?
(The question behind this being: I use this code to I/O large data, such as a PDF, from a regular DB, will it choke if more users ask for the same kind of data at the same time?)

Here is the logs:

GET msg client-2

1> mydb_client_handler:handle_command_line({ok, Data}, Socket)
mydb_client_handler:parse_command(Data)
mydb_client_handler:handle_command_re_result({match, [Command, Arg]})
mydb_client_handler:handle_command({"GET", Key}, Socket)
mydb_client_handler:db_get(Key)
mydb_data:get(Key) / <0.77.0>
mydb_data:handle_msg({get, Key}, _From, Db) / <0.69.0>
mydb_db:get(Db, Key) / <0.69.0>
mydb_db:handle_dets_lookup([{_Key, Value}]) / <0.69.0>
mydb_client_handler:handle_reply(Reply, Socket) / Reply = {ok,"TEST MSG"}
mydb_client_handler:send_reply({ok, Val}, Socket)
mydb_client_handler:handle_task(Socket)
mydb_client_handler:read_line(Socket)

GET msg client-1

1> mydb_client_handler:handle_command_line({ok, Data}, Socket)
mydb_client_handler:parse_command(Data)
mydb_client_handler:handle_command_re_result({match, [Command, Arg]})
mydb_client_handler:handle_command({"GET", Key}, Socket)
mydb_client_handler:db_get(Key)
mydb_data:get(Key) / <0.76.0> <<< PID IS ≠ FROM client-2 - OK
mydb_data:handle_msg({get, Key}, _From, Db) / <0.69.0> <<< PID IS = FROM client-2 - WEIRD (CHOKE POINT ???)
mydb_db:get(Db, Key) / <0.69.0>
mydb_db:handle_dets_lookup([{_Key, Value}]) / <0.69.0>
mydb_client_handler:handle_reply(Reply, Socket) / Reply = {ok,"TEST MSG"}
mydb_client_handler:send_reply({ok, Val}, Socket)
mydb_client_handler:handle_task(Socket)
mydb_client_handler:read_line(Socket)

Anyway, thanks for e2, as it helps a lot to understand how Erlang works.

Is this a bug?

Hi,

While testing the tasks example, I had an issue; tasks:start_tasks(10) worked,
but tasks:start_repeating(150, 20) returned that:

3> tasks:start_repeating(150, 20).
** exception error: no function clause matching e2_service_impl:split_options(repeating,150,[],[]) (../../src/e2_service_impl.erl, line 78)
in function e2_task:start_link/3 (../../src/e2_task.erl, line 57)
4>

replace appmon with observer in tutorial

In OTP 17, OTP-10915 replaces appmon with observer. Perhaps this should be reflected in the tutorial.

Project status?

Hi! What's the status on this project? There are quite a few TODOs mentioned, and not much activity lately. Is the implementation complete enough, or is it lack of time/interest from community?

Example logger C part have a problem with Erlang/20 erl_driver.h

Debian stretch (stable)
erlang-solutions Erlang/20 pkgs

Hi,

Trying to test it, it returns:

=ERROR REPORT==== 26-Sep-2017::17:20:47 ===
Error loading driver: Driver compiled with incorrect version of erl_driver.h
=CRASH REPORT==== 26-Sep-2017::17:20:47 ===
crasher:
initial call: syslog:init/1
pid: <0.75.0>
registered_name: []
exception exit: bad_driver
in function gen_server:init_it/6 (gen_server.erl, line 349)
ancestors: [syslog_sup,<0.73.0>]
message_queue_len: 0
messages: []
links: [<0.74.0>]
dictionary: []
trap_exit: false
status: running
heap_size: 376
stack_size: 27
reductions: 232
neighbours:

=SUPERVISOR REPORT==== 26-Sep-2017::17:20:47 ===
Supervisor: {local,syslog_sup}
Context: start_error
Reason: bad_driver
Offender: [{pid,undefined},
{id,syslog},
{mfargs,{syslog,start_link,[]}},
{restart_type,permanent},
{shutdown,5000},
{child_type,worker}]

=CRASH REPORT==== 26-Sep-2017::17:20:47 ===
crasher:
initial call: application_master:init/4
pid: <0.72.0>
registered_name: []
exception exit: {{shutdown,{failed_to_start_child,syslog,bad_driver}},
{syslog_app,start,[normal,[]]}}
in function application_master:init/4 (application_master.erl, line 134)
ancestors: [<0.71.0>]
message_queue_len: 1
messages: [{'EXIT',<0.73.0>,normal}]
links: [<0.71.0>,<0.33.0>]
dictionary: []
trap_exit: true
status: running
heap_size: 376
stack_size: 27
reductions: 185
neighbours:

=INFO REPORT==== 26-Sep-2017::17:20:47 ===
application: syslog
exited: {{shutdown,{failed_to_start_child,syslog,bad_driver}},
{syslog_app,start,[normal,[]]}}
type: temporary
** exception error: {error,{{shutdown,{failed_to_start_child,syslog,bad_driver}},
{syslog_app,start,[normal,[]]}}}
in function e2_application:start_apps/1 (../../src/e2_application.erl, line 139)
in call from e2_application:start_with_dependencies/1 (../../src/e2_application.erl, line 50)
2>