问题描述
systemd具有一个 EnvironmentFile 指令，该指令根据许多规则从文件的内容设置环境变量，这些规则与外壳解析该文件的方式相当不相同.
systemd has an EnvironmentFile directive, which sets environment variables from a file's contents based on a number of rules, which are not quite equivalent to how a shell would parse that file.
我该如何像使用systemd本身一样准确地解析 中的systemd EnvironmentFile ?
How can I parse a systemd EnvironmentFile in exactly the same way that systemd itself would?
推荐答案
最确定的事情是让systemd通过临时服务解析文件本身.因此:
The surest thing is to let systemd parse the file itself, via a transient service. Thus:
# emit a NUL-delimited set of key=value definitions for environment variables defined by a set of files
newVarsForFile_nullsep() {
local -a extraParams=( ); local file
(( $# )) || return 0 # no files specified, nothing to do
for file in "$@"; do
extraParams+=( --property=EnvironmentFile="$file" )
done
comm -z -23 \
<(sort -z < <(systemd-run --user --pipe "${extraParams[@]}" grep -zvE '^INVOCATION_ID=' /proc/self/environ </dev/null)) \
<(sort -z < <(systemd-run --user --pipe grep -zvE '^INVOCATION_ID=' /proc/self/environ </dev/null) )
}
# emit code that can be eval'd in an instance of bash to precisely define the exact variables
newVarsForFile_shellscript() {
while IFS= read -r -d '' vardef; do
printf '%s=%q\n' "${vardef%%=*}" "${vardef#*=}"
done < <(newVarsForFile_nullsep "$@")
}
此后，可以调用(作为示例):
Thereafter, one may invoke (as an example):
newVarsForFile_shellscript /etc/conf.d/*.conf
...发出一个shell脚本片段，当由bash执行该片段时，它将设置所有与将相关 EnvironmentFile s添加到服务定义中相同的环境变量.
...to emit a shell script fragment which, when executed by bash, will set all the same environment variables that adding the relevant EnvironmentFiles to a service definition would set.
这篇关于如何确定systemd EnvironmentFile可以设置的精确环境变量集?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！