[YARN-1479] Invalid NaN values in Hadoop REST API JSON response

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.23.6, 2.0.4-alpha
• Fix Version/s: 2.5.0
• Assignee: Chen He
• Reporter: Kendall Thrapp
• Created: 16/May/13 20:29
• Updated: 03/Sep/14 20:35
• Resolved: 19/Feb/14 17:56

Description

I've been occasionally coming across instances where Hadoop's Cluster Applications REST API (http://hadoop.apache.org/docs/r0.23.6/hadoop-yarn/hadoop-yarn-site/ResourceManagerRest.html#Cluster_Applications_API) has returned JSON that PHP's json_decode function failed to parse. I've tracked the syntax error down to the presence of the unquoted word NaN appearing as a value in the JSON. For example:

"progress":NaN,

NaN is not part of the JSON spec, so its presence renders the whole JSON string invalid. Hadoop needs to return something other than NaN in this case – perhaps an empty string or the quoted string "NaN".