add "-c" to flock call so variables get passed to command executed by run-one

[toobuntu]

I have a cronjob which, for convenience and safety, requires two variables to be passed to it in production. This is not possible the way run-one calls flock, unless the script is called with sh -c, which presumably forks a new process and does not seem streamlined, or the variables are passed to run-one, too, which does not seem elegant.

The below diff fixes this behavior for me:

$ diff -Nru a/run-one b/run-one
--- a/run-one 2013-03-04 18:02:15.513983439 -0500
+++ b/run-one 2013-03-04 18:24:42.414039276 -0500
@@ -32,6 +32,7 @@
 mkdir -p "$DIR"

 # Calculate the hash of the command and arguments
+CMD="$@"
 CMDHASH=$(echo "$@" | md5sum | awk '{print $1}')
 FLAG="$DIR/$CMDHASH"

@@ -39,7 +40,7 @@
 case "$(basename $0)" in
  run-one)
   # Run the specified commands, assuming we can flock this command string's hash
- flock -xn "$FLAG" "$@"
+ flock -xn "$FLAG" -c "$CMD"
  ;;
  run-this-one)
   ps="$@"
@@ -59,14 +60,14 @@
   [ -z "$pid" ] || kill $pid
   sleep 0.1
   # Run the specified commands, assuming we can flock this command string's hash
- flock -xn "$FLAG" "$@"
+ flock -xn "$FLAG" -c "$CMD"
  ;;
  keep-one-running)
   backoff=1
   while true; do
    # Run the specified commands, assuming we can flock this command string's hash
    set +e
- flock -xn "$FLAG" "$@"
+ flock -xn "$FLAG" -c "$CMD"
    if [ "$?" = 0 ]; then
     # Last run finished successfully, reset to minimum back-off of 1 second
     backoff=1

------------------
This will do it, but I'm not sure if invoking /bin/sh launches a new process to do so, and want to keep system resource usage as minimal as possible:
$ /usr/bin/run-one /bin/sh -c 'DEBUG=n TEST=n /usr/local/bin/rsync-daily.sh'

The following fail because of the way run-one invokes flock and passing the command as "$@", flock tries to create a lock on the first parameter passed to /usr/bin/run-one:
$ /usr/bin/run-one DEBUG=n TEST=n /usr/local/bin/rsync-daily.sh
flock: DEBUG=n: No such file or directory
$ /usr/bin/run-one 'DEBUG=n TEST=n /usr/local/bin/rsync-daily.sh'
flock: DEBUG=n TEST=n /usr/local/bin/rsync-daily.sh: No such file or directory

The following fails because the variables do not get passed to the script:
$ /usr/bin/run-one /usr/local/bin/rsync-daily.sh DEBUG=n TEST=n
status: testing $DEBUG...
+ rsync_opts=-v --progress -ah --stats --delete --numeric-ids
+ printf DEBUG != n, debug mode activated\n
DEBUG != n, debug mode activated
+ printf status: testing $TEST...\n
status: testing $TEST...
+ test y = n
+ rsync_opts=-n -v --progress -ah --stats --delete --numeric-ids
+ printf TEST != n, test mode activated\n
TEST != n, test mode activated

I tried playing around with xargs with no luck. For elegance, I'd rather not pass the variables to run-one itself, though this does work:
$ DEBUG=n TEST=n /usr/bin/run-one /usr/local/bin/rsync-daily.sh
status: testing $DEBUG...
DEBUG = n
status: testing $TEST...
TEST = n
---
ApportVersion: 2.0.1-0ubuntu17.1
Architecture: amd64
DistroRelease: Ubuntu 12.04
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120226)
MarkForUpload: True
Package: run-one 1.7-0ubuntu1 [modified: usr/bin/run-one]
PackageArchitecture: all
ProcVersionSignature: Ubuntu 3.5.0-25.38~precise1-generic 3.5.7.4
Tags: precise
Uname: Linux 3.5.0-25-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare staff sudo

[toobuntu (toobuntu)]

apport information

[toobuntu (toobuntu)]

apport information

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "allow passing variables to command to be invoked by run-one" of this bug report has been identified as being a patch. The ubuntu-reviewers team has been subscribed to the bug report so that they can review the patch. In the event that this is in fact not a patch you can resolve this situation by removing the tag 'patch' from the bug report and editing the attachment so that it is not flagged as a patch. Additionally, if you are member of the ubuntu-reviewers team please also unsubscribe the team from this bug report.

[This is an automated message performed by a Launchpad user owned by Brian Murray. Please contact him regarding any issues with the action taken in this bug report.]

[toobuntu (toobuntu)]

Nitpicking grammar in my own patch...

Here's a slightly better patch, only because man flock(1) clarifies that one can pass only a single command with direct invocation of flock. Below the synopsis are three other quotes from the man page. Only the third form, which is not used by run-one, allows multiple commands to be run.

SYNOPSIS
       flock [-sxon] [-w timeout] lockfile [-c] command...
       flock [-sxon] [-w timeout] lockdir [-c] command...
       flock [-sxun] [-w timeout] fd

Pass a single command to the shell with -c.
The first and second forms wraps the lock around the executing a command, in a manner similar to su(1) or newgrp(1).
The third form is convenient inside shell scripts, and is usually used
       the following manner:

       (
         flock -n 9 || exit 1
         # ... commands executed under lock ...
       ) 9>/var/lock/mylockfile

$ diff -Nru a/run-one b/run-one
--- a/run-one 2013-03-04 18:02:15.513983439 -0500
+++ b/run-one 2013-03-05 15:27:46.635948096 -0500
@@ -32,14 +32,15 @@
 mkdir -p "$DIR"

 # Calculate the hash of the command and arguments
+CMD="$@"
 CMDHASH=$(echo "$@" | md5sum | awk '{print $1}')
 FLAG="$DIR/$CMDHASH"

 # Handle run-this-one invocation, by killing matching process first
 case "$(basename $0)" in
  run-one)
- # Run the specified commands, assuming we can flock this command string's hash
- flock -xn "$FLAG" "$@"
+ # Run the specified command, assuming we can flock this command string's hash
+ flock -xn "$FLAG" -c "$CMD"
  ;;
  run-this-one)
   ps="$@"
@@ -58,15 +59,15 @@
   pid=$(lsof "$FLAG" | awk '{print $2}' | grep "^[0-9]") || true
   [ -z "$pid" ] || kill $pid
   sleep 0.1
- # Run the specified commands, assuming we can flock this command string's hash
- flock -xn "$FLAG" "$@"
+ # Run the specified command, assuming we can flock this command string's hash
+ flock -xn "$FLAG" -c "$CMD"
  ;;
  keep-one-running)
   backoff=1
   while true; do
- # Run the specified commands, assuming we can flock this command string's hash
+ # Run the specified command, assuming we can flock this command string's hash
    set +e
- flock -xn "$FLAG" "$@"
+ flock -xn "$FLAG" -c "$CMD"
    if [ "$?" = 0 ]; then
     # Last run finished successfully, reset to minimum back-off of 1 second
     backoff=1

[Launchpad Janitor (janitor)]

This bug was fixed in the package run-one - 1.10-0ubuntu1

---------------
run-one (1.10-0ubuntu1) saucy; urgency=low

  * No changes
  * Re-release, due to minor errors in release script
 -- Dustin Kirkland <email address hidden> Tue, 16 Jul 2013 14:55:49 -0500