Forum: CFEngine Help
Subject: Re: Append the content of file to another one without checking for
duplicate lines
Author: zzamboni
Link to topic: https://cfengine.com/forum/read.php?3,26695,26700#msg-26700
I think CFEngine resists doing this because it makes it impossible to assure
convergence. If you have a promise that appends a file to another without any
checks, it will be appended every time the promise runs. There is no way to
guarantee that it will ever reach a stable situation.
One way to do this would be with a transformer attribute. This works:
"/tmp/bigfile"
create => "true",
transformer => "/usr/bin/perl -e 'BEGIN { open(F1,
q(>$(this.promiser))) } while() { print F2 $_ }'";
Note that transformer runs the command without a shell, so you can't simply use
"cat /tmp/bigdata >> $(this.promiser)". I used a perl one-liner, but it could
be anything else that performs the append on the file.
This runs very quickly:
$ /usr/bin/time cf-agent -K -f ./test-insertfile.cf
0.15 real 0.10 user 0.02 sys
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