<div dir="ltr">you are welcome iggor but i think we may be talking about two different things<div>the relx section like below</div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><span style="white-space:pre"> </span>{release, {"app_release", "0.3.3"},[app_name,mnesia]},</blockquote><div>would be one way to include mnesia and to have libs added as part of the release and mnesia started when your application is started . </div><div>another way which is what i was talking about would be to add it in the .app.src file like this</div><div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> {applications,[kernel,stdlib,mnesia ]}</blockquote><div>you may want mnesia to be started only when specific applications are started not when the whole release is started .</div></div><div><br></div><div>cheers!!</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sun, Apr 15, 2018 at 9:01 PM, Igor Clark <span dir="ltr"><<a href="mailto:igor.clark@gmail.com" target="_blank">igor.clark@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
Thanks very much Nuku, that's the piece of the puzzle I was missing.
I hadn't understood properly about the release packaging - I thought
that if I added mnesia into the relx config, it would automatically
start the mnesia app too, and I wanted to do that manually in my
app. But after reading your email I added it into the relx/release
section, and as you said, the mnesia package is now included in the
release, but I can still start it manually, and the console boots
correctly and accesses the mnesia data. <br>
<br>
Thank you!<br>
<br>
Best,<br>
Igor<div><div class="h5"><br>
<br>
<div class="m_4933564755850586988moz-cite-prefix">On 15/04/2018 21:01, Nuku Ameyibor
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr"> mnesia is not included as part of the release .
<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;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">when
rebar3 shell command is run the path to mnesia is added
automatically to the code paths .</span></div>
<div>in a release environment however its not copied over <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">into
the release libs</span> unless specified in one of your
.app.src files.</div>
<div>in your app.src file check to see if mnesia is one of the
applications which has to be started before the main
application is started.</div>
<div><br>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Sun, Apr 15, 2018 at 3:50 PM, Igor
Clark <span dir="ltr"><<a href="mailto:igor.clark@gmail.com" target="_blank">igor.clark@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"> 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
<div>
<div class="m_4933564755850586988h5"><br>
<br>
<div class="m_4933564755850586988m_1109125637984098877moz-cite-prefix">On
15/04/2018 16:06, Nuku Ameyibor wrote:<br>
</div>
<blockquote type="cite">
<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><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"><wbr>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-wrap"> </span>[</div>
<div><span style="white-space:pre-wrap"> </span>{sys_config,"config/sys.config<wbr>"}</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-wrap"> </span>{mnesia, </div>
<div><span style="white-space:pre-wrap"> </span>[{dir,"/tmp/my_db_dir"}]</div>
<div><span style="white-space:pre-wrap"> </span>},</div>
<div><span style="white-space:pre-wrap"> </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-wrap"> </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-wrap"> </span><br>
</div>
<div><span style="white-space:pre-wrap"> </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" target="_blank">http://www.rebar3.org/docs<wbr>/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">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>
</div>
</div>
</div>
</blockquote>
</div>
<br>
</div>
</blockquote>
<br>
</div></div></div>
</blockquote></div><br></div>