Re: .env file handling
See also rc(1) :) On Tue, Oct 24, 2017 at 10:55:28PM +0200, Guillaume Perréal wrote: > The scoping might be a bit challenging, but the variable substitution system > is royal. I do not constantly ask myself "what will happen if this variable > contains a space, or a quote ?". -- My current OpenPGP key: RSA4096/0x227E8CAAB7AA186C (expires: 2020.10.19) 7077 7781 B859 5166 AE07 0286 227E 8CAA B7AA 186C
Re: .env file handling
Le 24/10/2017 à 08:28, Colin Booth a écrit : I would say that is one of the two difficulties. The other one being that execline also tries hard not to carry any overhead, which means that often times you can end up in situations where the aggressive scoping that it does makes things challenging at best (assuming you're trying to stay with the spirit of the language). The scoping might be a bit challenging, but the variable substitution system is royal. I do not constantly ask myself "what will happen if this variable contains a space, or a quote ?". -- Guillaume.
Re: .env file handling
Thank you for the explanations and solutions, things are starting to make more sense now. I can live with the envdir approach for my docker containers, or provide a tool to parse .env files and create the envdir when loading in the settings but before launching a program. Thanks, Monty On Oct 23, 2017, 11:22 PM -0700, wrote: > > The underlying difficulty with Monty's question is that execline tries > to avoid parsing as much as possible, and a file full of key=value > lines, > as simple as it is, still requires some parsing. execline wasn't made > for this; the idiomatic way to store key-value pairs in the filesystem > for use by an execline script is, as Monty found out, s6-envdir. > If you really want a shell-like syntax, the best way to handle it is > with tools that already understand this syntax, such as a shell, or as > Casper suggested, env.
Re: .env file handling
I tried rewriting the whole thing in execline and while I'm pretty sure
it's doable it's not easy.
A direct translation of Casper's script to execline could be:
#!/command/execlineb -P
backtick LIST { cat /path/to/xyz.env }
importas -nsd"\n" LIST LIST
env -i ${LIST}
/path/to/xyz
It's not as idiomatic as other ways to handle variables in execline,
but it should work.
The underlying difficulty with Monty's question is that execline tries
to avoid parsing as much as possible, and a file full of key=value
lines,
as simple as it is, still requires some parsing. execline wasn't made
for this; the idiomatic way to store key-value pairs in the filesystem
for use by an execline script is, as Monty found out, s6-envdir.
If you really want a shell-like syntax, the best way to handle it is
with tools that already understand this syntax, such as a shell, or as
Casper suggested, env.
--
Laurent
Re: .env file handling
On Tue, Oct 24, 2017 at 09:25:37AM +0800, Casper Ti. Vector wrote:
> > #!/bin/sh
> > exec env -i $(cat /path/to/xyz.env) /path/to/xyz
> And of course you should be careful with the contents in `xyz.env'.
>
You can do the same with
#!/bin/sh
while read A ; do
export "$A"
done < "$1"
exec prog...
If you don't want to use cat.
I tried rewriting the whole thing in execline and while I'm pretty sure
it's doable it's not easy. The problem is that scope in execline doesn't
extend past the execution context of a given program, so while the
following program looks like it should work, it doesn't:
#!/command/execlineb
elgetpositionals
redirfd -r 0 $1
withstdinas -n VAR
prog...
since prog will get run with the environmental variable VAR set to the
entire contents of your file.
Changing it to the following to unwrap VAR ends up with you setting the
variables correctly each loop, but not getting everything pulled into
the environment at once due to the aforementioned scoping:
#!?command/execlineb
elgetpositionals
redirfd -r 0 $1
foreground {
forstdin VAR
importas -usd= VAR VAR
export ${VAR}
s6-echo ""
}
prog...
You can test that it's setting the variables and then losing them by
change `s6-echo ""' to `env'. And setting prog... to
`foreground { s6-echo "" } env'
Hope is however not all lost. You can do it with execline and s6 as long
as you have a tmpfs laying around somewhere:
#!/command/execlineb
elgetpositionals
foreground { mkdir -p /run/envdir }
redirfd -r 0 $1
foreground {
forstdin -Cd"\n" VAR
importas -u VAR VAR
multidefine -d= ${VAR} { K V }
redirfd -w 1 /run/envdir/${k}
s6-echo ${V}
}
s6-envdir /run/envdir
prog...
That does create a directory somewhere, but it parses a multi-line K=V
style file into something that s6-envdir can handle.
Oh, and it should go without saying, but all these script snippets
assume that you're calling them as `script /path/to/envfile'
Cheers!
--
Colin Booth
.env file handling
Hi all, I've been learning about s6 through the s6-overlay. What I would like to do is take a .env file full of x=y lines and have that define env vars before running a program. I suspect there is a clever and easy way to do that. However, I'm not so clever. The best I've found so far is the s6-envdir program. I've also been reading the man page for execline which I like in theory but similarly just can't quite get my head around. I've been searching for some example scripts but I haven't found much beyond the man pages which tend to narrowly focus on one topic. Thanks for any tips, Monty
