Nodejs process hang, how could I debug it or collect dump?

node.js debugging process dump freeze
kevin_song picture kevin_song · Jul 24, 2014 · Viewed 12k times · Source

my nodejs process which was running at Linux, now it is hang and the CPU is 100%. Is there anyway I can do to debug it and find the reason? Do I need to collect dump and how? Thanks.

Answer

B T picture B T · Nov 18, 2017

There's an npm module called why-is-node-running that can give you info like:

There are 4 known handle(s) keeping the process running and 0 unknown
Known handles:

# Timer
/Users/maf/dev/node_modules/why-is-node-running/example.js:6  - setInterval(function () {}, 1000)
/Users/maf/dev/node_modules/why-is-node-running/example.js:10 - createServer()

# TCP
/Users/maf/dev/node_modules/why-is-node-running/example.js:7  - server.listen(0)
/Users/maf/dev/node_modules/why-is-node-running/example.js:10 - createServer()

# TCP
/Users/maf/dev/node_modules/why-is-node-running/example.js:7  - server.listen(0)
/Users/maf/dev/node_modules/why-is-node-running/example.js:11 - createServer()

# Timer
/Users/maf/dev/node_modules/why-is-node-running/example.js:13 - setTimeout(function () {

Related questions

How can I get the full object in Node.js's console.log(), rather than '[Object]'?

When debugging using console.log(), how can I get the full object? const myObject = { "a":"a", "b":{ "c":"c", "d":{ "e":"e", "f":{ "g":"g", "h":{ "i":"i" } } } } }; console.log(myObject); Outputs: { a: 'a', b: { c: 'c', d: { e: 'e', …

Read More
How do I debug Node.js applications?

How do I debug a Node.js server application? Right now I'm mostly using alert debugging with print statements like this: sys.puts(sys.inspect(someVariable)); There must be a better way to debug. I know that Google Chrome has …

Read More
How do I debug "Error: spawn ENOENT" on node.js?

When I get the following error: events.js:72 throw er; // Unhandled 'error' event ^ Error: spawn ENOENT at errnoException (child_process.js:1000:11) at Process.ChildProcess._handle.onexit (child_process.js:791:34) What procedure can I follow to fix it? Author note: Lots …

Read More