Modifying Jenkins Description for a build

I would like to remotely change a Jenkins build description. I have my script all set and ready except for one tiny problem: Multiple line descriptions.

I am using the REST API and JSON in Jenkins to download the old description:

old_description=$(curl -s --user "$USER:$PASSWORD" --data-urlencode "tree=description" \
    "$jenkins_url/job/$job_name/$build_number/api/json")

old_description=${old_description#*:\"} #Remove JSON garbage
old_description=${old_description%\"\}} #Remove JSON garbage

The `curl command pulls out:

<font color=blue><b>At first you don't succeed. Try again</b></font><br/>
\r\n<font color=gold><b>At first you don't succeed. Try again</b></font><br/>
\r\n<font color=green><b>At first you don't succeed. Try again</b></font>

(Note: I added line breaks to make the above easier to read. This is pulled out as a single line).

The \r\n are separate lines, so I do this:

old_description=$(sed 's/\\r\\n/\
/g' <<<$old_description)

And that changes $old_description to:

font color=blue><b>At first you don't succeed. Try again</b></font><br/>
<font color=gold><b>At first you don't succeed. Try again</b></font><br/>
<font color=green><b>At first you don't succeed. Try again</b></font>

(NOTE: The new lines are part of the value. This is a three line description.)

My program (depending upon the command line parameters) can replace, append, or prepend a new description to the build:

if [ "$prepend_flag" -a -n "$old_description" ] #Prepend new description to old description
then
    new_description="$new_description<br/>
$old_description"
elif [ "$append_flag" -a -n "$old_description" ] #Append new description to old description
then
   new_description="$old_description<br/>
$new_description"
fi

Now, I'll redo the description:

if curl -u $USER:$PASSWORD   --data-urlencode "description=$new_description" \
    --data-urlencode "Submit=Submit" \
    "$jenkins_url/job/$job_name/$build_number/submitDescription"
then
    echo "Description successfully changed on Build #$build_number in Jenkins job $job_name"
else
    echo "WARNING: Description was not set. Manually change the descripiton of the build"
    echo "         for Build #$build_number in Jenkins job $job_name"
fi

If I am prepending or appending the new description the first time, I get this in Jenkins:

<font color=blue><b>At first you don't succeed. Try again</b></font><br/>
<font color=gold><b>At first you don't succeed. Try again</b></font><br/>
<font color=green><b>At first you don't succeed. Try again</b></font><br/>
<font color=red><b>My new description</b></font><br/>

Looks nice. The next time, it doesn't work. I get this:

<font color=blue><b>At first you don't succeed. Try again</b></font><br/>\n<font color=gold><b>At first you don't succeed. Try again</b></font><br/>\n<font color=green><b>At first you don't succeed. Try again</b></font><br/>\n<font color=red><b>My new description</b></font><br/>
<font color=blue><b>My new new description</b></font>

Note the \n showing up.

How can I fix this issue?

I've put the whole program in pastebin.

Solution

I played around with this for a long while...

First, instead of doing this:

    new_description="$new_description<br/>
$old_description"

to append or prepend the line, I used printf:

new_description="$(printf "$new_description\r\n$old_description")"

By using printf, I put a <CR><LF> instead of just a <LF> in my description line separator. This way, I don't have a jumble of <NL> and <CR><NL> and I'm no longer dependent upon the operating system's definition of the line break.

The sed command took me a long, long time to figure out. I tried all sorts of things:

old_description=$(sed 's/\\r\\n/\r\n/g' <<<$old_description)

But, nothing seemed to work... I tried the -E flag which allows me to use the extended regular expressions, but it kept interpreting \r\n as replacing \\r\\n with literal 'rn.

After several hours of this, I finally tried double quotation marks instead of single quotation marks:

old_description=$(sed "s/\\r\\n/\r\n/g" <<<$old_description)

That worked! You normally use single quotation marks with sed to protect the regular expression from interpolation. However, the single quotes were also killing the interpolation of \r\n as <CR><LF>. Changing them with double quotes solved the problem.