missing "env" directory

[mbuczko]

for the following (generated) "run" command:

BASE_DIR=/opt/foo/bar
JAR=bar-1.0.0.jar
exec 2>&1
exec chpst -u root -e $BASE_DIR/env java -jar -server $BASE_DIR/$JAR

looks like missing "env" dir in $BASE_DIR prevents jar file from getting executed and log file is flooded with:

chpst: fatal: unable to switch to directory: /opt/foo/bar/env: file does not exist

would be nice to have "env" dir auto-created :)

[danielsz]

Hi,

env is not a directory, but a binary present on GNU/Linux systems that allows you to launch programs without having to hard-code their path.

[mbuczko]

that was also my first thought and I was surprised by the message about missing dir (btw. I'm running it within docker based on Ubuntu 14.04 where env as a binary obviously does exist).
anyway, I looked at the chpst man and it states clearly:

-e dir
    envdir. Set various environment variables as specified by files in the directory dir.

this is why

chpst -u root -e $BASE_DIR/env

treats $BASE_DIR/env as dir rather than binary file (or at least I guess so).

[danielsz]

I was totally wrong. I wasn't focused and missed the essence of your report. This also reminds me why I wrote boot-runit: so I won't need to remember the minutiae to setup runit every time .

So it goes like this: env is a directory where runit stores environment variables. If you type man chpst, you will notice the -e switch:

envdir. Set various environment variables as specified by files in the directory dir: If dir contains a file named k whose first line is v, chpst removes the environment variable k if it exists, and then adds the environment variable k with the value v. The name k must not contain =. Spaces and tabs at the end of v are removed, and nulls in v are changed to newlines. If the file k is empty (0 bytes long), chpst removes the environment variable k if it exists, without adding a new variable.

And this is how you invoke boot-runit in build-boot:

(deftask prod
  "deploy with runit"
  []
  (comp
   (build)
   (runit :env {:redis-instance "localhost"
                  :geoip-server "http://example.net:9090/json/"
                  :mongo-url "mongodb://example.com/example-db"})))

boot-runit will create the env directory for you according to that map. That is one of those things it does to alleviate the ceremony involved with runit.

And build, if you were wondering, is:

(deftask build
  "Builds an uberjar of this project that can be run with java -jar"
  []
  (comp
   (aot :namespace '#{example.main})
   (pom :project 'example
        :version "1.0.0")
   (uber)
   (jar :main 'example.main)))

Note: If your application doesn't use environment variables at all, you can try and manually remove the -e switch in run.

exec chpst -u root java -jar -server $BASE_DIR/$JAR

I hope this helps.

[mbuczko]

thanks for detailed answer. now, comming back to my initial idea wouldn't it be much easier and less confusing if the env dir was created by default (even if no :env's were provided) instead of modifying generated run? if it's a problem I may try to dig around and prepare some PR.

[danielsz]

All my apps use environment variables, so it didn't cross my mind, but sure, what you're proposing makes sense. A PR will be very welcome. Thank you.

Bonus points if you make it so that no -e switch appears in the run file when no environment variables are used. In that case, we don't need to create the env dir at all.