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Thanks Nuku,<br>
<br>
- It's definitely crashing due to the mnesia configuration - it
shows a <tt>{badmatch,undefined}</tt> error on the line where I
call <tt>{ ok, MnesiaDir } = application:get_env( mnesia, dir )</tt>,
and I've tried <tt>io:format()</tt>'ing the result of <tt>application:get_env(
mnesia, dir )</tt>, which shows '<tt>undefined</tt>' when running
as a release<br>
<br>
- relx section of rebar.config is set up exactly like that - I used
rebar3 to generate the release<br>
<br>
- sys.config has exactly that mnesia entry<br>
<br>
It all works as expected with 'rebar3 shell', environment variable
is found, mnesia starts, it all works fine - but when I run 'rebar3
release' and try to run the generated startup script, either with
'console' or with 'start' and looking in the log file, the OTP
application included in the release gets '<tt>undefined</tt>' from <tt>application:get_env(
mnesia, dir )</tt>.<br>
<br>
From your sys.config example I realise I could say for example <tt>[
{ my_app, [ { mnesia_dir, "/tmp/my_db_dir" } ] } ]</tt>, and use
application:get_env( my_app, mnesia_dir ) to initialise; this works
and returns <tt>{ ok, "/tmp/my_db_dir" }</tt>, which is great, but
then <tt>ok = application:ensure_started( mnesia )</tt> fails with
<tt>{{badmatch, {error,{"no such file or directory","mnesia.app"}}}</tt>.
I have no idea where <tt>mnesia.app</tt> should go, and I haven't
been able to find any references to this file in docs or online that
explain where it should go or what should be in it, except that it
exists in the mnesia package under the OTP source tree.<br>
<br>
So still pretty unclear how to proceed, pointers welcome!<br>
<br>
Thanks,<br>
Igor<br>
<br>
<div class="moz-cite-prefix">On 15/04/2018 16:06, Nuku Ameyibor
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAOo93=9C_+YVpREoecMWrs4HwkDxMRf8EP76mGGiYegwoZC3ag@mail.gmail.com">
<div dir="ltr">
<div>
<div><br>
</div>
<blockquote class="gmail_quote"
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;margin:0px
0px 0px 0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex"><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">
- under_build/<profile>/rel/<rel</span><wbr
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">ease>/bin/<release>
console it fails (returns undefined), so the app crashes
on start, regardless of whether <profile> is prod or
default</span></blockquote>
<span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial;background-color:rgb(255,255,255);float:none;display:inline">it
may or may not be crashing due the mnesia configuration .</span>
<div
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial">you
may have to check the the erl_crash.dump to see the cause of
the crash . </div>
<div
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><br>
</div>
<div
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><br>
</div>
<div
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial">
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex"><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">How
do I set mnesia application environment variables in the
release project? (Or, maybe, how do I get the OTP
application to be able to access the release project's
application environment variables?)</span></blockquote>
<div> </div>
<div>in the relx section of your rebar.config you can set a
sys_config to be used</div>
<div>
<div>{relx, </div>
<div><span style="white-space:pre"> </span>[</div>
<div><span style="white-space:pre"> </span>{sys_config,"config/sys.config"}</div>
</div>
<div> ]</div>
<div> </div>
in that sys.config you can setup environmental variables to
be used by your applications including an entry for mnesia.</div>
<div
style="text-align:start;text-indent:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial">
<div>[</div>
<div><span style="white-space:pre"> </span>{mnesia, </div>
<div><span style="white-space:pre"> </span>[{dir,"/tmp/my_db_dir"}]</div>
<div><span style="white-space:pre"> </span>},</div>
<div><span style="white-space:pre"> </span>{app1,[{a,1},{b,2}],</div>
<div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;white-space:pre"> </span><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">{app2,[{a,3},{b,4}]</span><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;white-space:pre"> </span><br>
</div>
<div><span style="white-space:pre"> </span>}</div>
<div>]</div>
</div>
<div
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial">this
will be used by your release system when the release is
created .</div>
<div
style="text-align:start;text-indent:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial">check
out <a href="http://www.rebar3.org/docs/releases"
moz-do-not-send="true">http://www.rebar3.org/docs/releases</a> .<br>
</div>
<div
style="text-align:start;text-indent:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><br>
</div>
<div
style="text-align:start;text-indent:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><br>
</div>
</div>
<div
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><br>
</div>
<div> </div>
<div class="gmail_extra">
<div class="gmail_quote">On Sat, Apr 14, 2018 at 3:17 PM, Igor
Clark <span dir="ltr"><<a
href="mailto:igor.clark@gmail.com" target="_blank"
moz-do-not-send="true">igor.clark@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">Hi list,<br>
<br>
I have an OTP application which uses mnesia. It
checks/ensures the schema and table files exist and then
calls application:ensure_started( mnesia ) in its
application:start/2 callback. It works fine when I run the
application on its own under rebar3 shell, but it doesn't
work when I try to run it from an OTP release:<br>
<br>
- When I run the OTP app under rebar3 shell in its own
separate directory, with { mnesia, [ { dir,
"/tmp/my_db_dir" } ] } in priv/sys.config, it works fine
and application:get_env( mnesia, dir ) returns
/tmp/my_db_dir as normal/expected<br>
<br>
- If I set { mnesia, [ { dir, "/tmp/my_db_dir" } ] } in
<release>/config/sys.config, then:<br>
<br>
- under rebar3 shell --name=myapp@mynode, calling
application:get_env( mnesia, dir ) succeeds (returns
/tmp/my_db_dir) , and the app uses reads/writes mnesia
tables successfully<br>
<br>
- under_build/<profile>/rel/<rel<wbr>ease>/bin/<release>
console it fails (returns undefined), so the app crashes
on start, regardless of whether <profile> is prod or
default<br>
<br>
How do I set mnesia application environment variables in
the release project? (Or, maybe, how do I get the OTP
application to be able to access the release project's
application environment variables?)<br>
<br>
Also, I realise I could be going about this the wrong way
- maybe mnesia should be configured inside the specific
OTP app, even under a release? Apart from the fact that
that doesn't seem to work (as I have it set up, anyway),
I'm aware I should steer clear of "included applications"
- not least because I want to be able to use the OTP app
in other projects - so I guess there's a broader question
of how to configure mnesia in general, in how & when
to create schema and tables, if it could be used by
multiple OTP apps in a release?<br>
<br>
Bit puzzled, appreciate any advice!<br>
<br>
Cheers,<br>
Igor<br>
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</blockquote>
</div>
<br>
</div>
</div>
</blockquote>
<br>
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