Node.js EventEmitter handler memory leak
1
Is this a memory leak?
class Leaky {
constructor(options) {
process.on('message', function(msg) {
this.do_something(msg)
// ...
}.bind(this))
}
// ...
}
When I call new Leaky() a reference is bound to the instance through the handler. process is not going to be GC'd, so did I just leak the Leaky instance?
How can I prevent this? The only solution I can think of is having a dispose method that calls process.off, but I'd like to avoid that. I don't see something like unref or weak handlers on EventEmitter.
javascript node.js memory-leaks
asked Nov 15 '18 at 17:03
FoziFozi
3,8522450
|
show 1 more comment
1
Is this a memory leak?
class Leaky {
constructor(options) {
process.on('message', function(msg) {
this.do_something(msg)
// ...
}.bind(this))
}
// ...
}
When I call new Leaky() a reference is bound to the instance through the handler. process is not going to be GC'd, so did I just leak the Leaky instance?
How can I prevent this? The only solution I can think of is having a dispose method that calls process.off, but I'd like to avoid that. I don't see something like unref or weak handlers on EventEmitter.
javascript node.js memory-leaks
asked Nov 15 '18 at 17:03
FoziFozi
3,8522450
Do you need to add a new event handler for each instance ofLeaky? Could you store a list ofLeakys and have one handler that operates on that list? It would make it easier to remove the event handler when you don't have any more instances to work against.
– Mike Cluck
Nov 15 '18 at 17:10
1
Yes, this would prevent your instances from getting garbage collected. Does every instance of Leaky listen for the exact same message? If so, I can think of a different way to implement this that doesn't have this issue.
– jfriend00
Nov 15 '18 at 17:27
Why are you using both an arrow function and.bind(this)Pick one or the other.
– jfriend00
Nov 15 '18 at 17:28
1
@MikeCluck In the actual code it's notprocessbut another long livedEventEmitterthat is passed in the options. I thought about the indirection (only register one handler and execute from a list of handlers) but it does not solve the memory leak problem: in the end there has to be a list of handlers that reference every instance. I looked at WeakMap and WeakSet but they are not enumerable.
– Fozi
Nov 15 '18 at 18:14
@Fozi What exactly is the event emitter if it is notprocess? What are theLeakyentities, and how many are there (do they accumulate over time or is the number limited)? Also if theLeakyones are supposed to be shorter-lived than the event emitter, when exactly does their live end (i.e. when are they no longer needed)?
– Bergi
Nov 15 '18 at 21:01
|
show 1 more comment
1
1
1
Is this a memory leak?
class Leaky {
constructor(options) {
process.on('message', function(msg) {
this.do_something(msg)
// ...
}.bind(this))
}
// ...
}
When I call new Leaky() a reference is bound to the instance through the handler. process is not going to be GC'd, so did I just leak the Leaky instance?
How can I prevent this? The only solution I can think of is having a dispose method that calls process.off, but I'd like to avoid that. I don't see something like unref or weak handlers on EventEmitter.
javascript node.js memory-leaks
asked Nov 15 '18 at 17:03
FoziFozi
3,8522450
Is this a memory leak?
class Leaky {
constructor(options) {
process.on('message', function(msg) {
this.do_something(msg)
// ...
}.bind(this))
}
// ...
}
When I call new Leaky() a reference is bound to the instance through the handler. process is not going to be GC'd, so did I just leak the Leaky instance?
How can I prevent this? The only solution I can think of is having a dispose method that calls process.off, but I'd like to avoid that. I don't see something like unref or weak handlers on EventEmitter.
javascript node.js memory-leaks
javascript node.js memory-leaks
asked Nov 15 '18 at 17:03
FoziFozi
3,8522450
asked Nov 15 '18 at 17:03
FoziFozi
3,8522450
edited Nov 15 '18 at 18:11
Fozi
asked Nov 15 '18 at 17:03
FoziFozi
3,8522450
asked Nov 15 '18 at 17:03
FoziFozi
3,8522450
asked Nov 15 '18 at 17:03
FoziFozi
3,8522450
3,8522450
Do you need to add a new event handler for each instance ofLeaky? Could you store a list ofLeakys and have one handler that operates on that list? It would make it easier to remove the event handler when you don't have any more instances to work against.
– Mike Cluck
Nov 15 '18 at 17:10
1
Yes, this would prevent your instances from getting garbage collected. Does every instance of Leaky listen for the exact same message? If so, I can think of a different way to implement this that doesn't have this issue.
– jfriend00
Nov 15 '18 at 17:27
Why are you using both an arrow function and.bind(this)Pick one or the other.
– jfriend00
Nov 15 '18 at 17:28
1
@MikeCluck In the actual code it's notprocessbut another long livedEventEmitterthat is passed in the options. I thought about the indirection (only register one handler and execute from a list of handlers) but it does not solve the memory leak problem: in the end there has to be a list of handlers that reference every instance. I looked at WeakMap and WeakSet but they are not enumerable.
– Fozi
Nov 15 '18 at 18:14
@Fozi What exactly is the event emitter if it is notprocess? What are theLeakyentities, and how many are there (do they accumulate over time or is the number limited)? Also if theLeakyones are supposed to be shorter-lived than the event emitter, when exactly does their live end (i.e. when are they no longer needed)?
– Bergi
Nov 15 '18 at 21:01
|
show 1 more comment
Do you need to add a new event handler for each instance ofLeaky? Could you store a list ofLeakys and have one handler that operates on that list? It would make it easier to remove the event handler when you don't have any more instances to work against.
– Mike Cluck
Nov 15 '18 at 17:10
1
Yes, this would prevent your instances from getting garbage collected. Does every instance of Leaky listen for the exact same message? If so, I can think of a different way to implement this that doesn't have this issue.
– jfriend00
Nov 15 '18 at 17:27
Why are you using both an arrow function and.bind(this)Pick one or the other.
– jfriend00
Nov 15 '18 at 17:28
1
@MikeCluck In the actual code it's notprocessbut another long livedEventEmitterthat is passed in the options. I thought about the indirection (only register one handler and execute from a list of handlers) but it does not solve the memory leak problem: in the end there has to be a list of handlers that reference every instance. I looked at WeakMap and WeakSet but they are not enumerable.
– Fozi
Nov 15 '18 at 18:14
@Fozi What exactly is the event emitter if it is notprocess? What are theLeakyentities, and how many are there (do they accumulate over time or is the number limited)? Also if theLeakyones are supposed to be shorter-lived than the event emitter, when exactly does their live end (i.e. when are they no longer needed)?
– Bergi
Nov 15 '18 at 21:01
Do you need to add a new event handler for each instance of
Leaky? Could you store a list of Leakys and have one handler that operates on that list? It would make it easier to remove the event handler when you don't have any more instances to work against.– Mike Cluck
Nov 15 '18 at 17:10
Do you need to add a new event handler for each instance of
Leaky? Could you store a list of Leakys and have one handler that operates on that list? It would make it easier to remove the event handler when you don't have any more instances to work against.– Mike Cluck
Nov 15 '18 at 17:10
1
1
Yes, this would prevent your instances from getting garbage collected. Does every instance of Leaky listen for the exact same message? If so, I can think of a different way to implement this that doesn't have this issue.
– jfriend00
Nov 15 '18 at 17:27
Yes, this would prevent your instances from getting garbage collected. Does every instance of Leaky listen for the exact same message? If so, I can think of a different way to implement this that doesn't have this issue.
– jfriend00
Nov 15 '18 at 17:27
Why are you using both an arrow function and
.bind(this) Pick one or the other.– jfriend00
Nov 15 '18 at 17:28
Why are you using both an arrow function and
.bind(this) Pick one or the other.– jfriend00
Nov 15 '18 at 17:28
1
1
@MikeCluck In the actual code it's not
process but another long lived EventEmitter that is passed in the options. I thought about the indirection (only register one handler and execute from a list of handlers) but it does not solve the memory leak problem: in the end there has to be a list of handlers that reference every instance. I looked at WeakMap and WeakSet but they are not enumerable.– Fozi
Nov 15 '18 at 18:14
@MikeCluck In the actual code it's not
process but another long lived EventEmitter that is passed in the options. I thought about the indirection (only register one handler and execute from a list of handlers) but it does not solve the memory leak problem: in the end there has to be a list of handlers that reference every instance. I looked at WeakMap and WeakSet but they are not enumerable.– Fozi
Nov 15 '18 at 18:14
@Fozi What exactly is the event emitter if it is not
process? What are the Leaky entities, and how many are there (do they accumulate over time or is the number limited)? Also if the Leaky ones are supposed to be shorter-lived than the event emitter, when exactly does their live end (i.e. when are they no longer needed)?– Bergi
Nov 15 '18 at 21:01
@Fozi What exactly is the event emitter if it is not
process? What are the Leaky entities, and how many are there (do they accumulate over time or is the number limited)? Also if the Leaky ones are supposed to be shorter-lived than the event emitter, when exactly does their live end (i.e. when are they no longer needed)?– Bergi
Nov 15 '18 at 21:01
|
show 1 more comment
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Do you need to add a new event handler for each instance of
Leaky? Could you store a list ofLeakys and have one handler that operates on that list? It would make it easier to remove the event handler when you don't have any more instances to work against.– Mike Cluck
Nov 15 '18 at 17:10
1
Yes, this would prevent your instances from getting garbage collected. Does every instance of Leaky listen for the exact same message? If so, I can think of a different way to implement this that doesn't have this issue.
– jfriend00
Nov 15 '18 at 17:27
Why are you using both an arrow function and
.bind(this)Pick one or the other.– jfriend00
Nov 15 '18 at 17:28
1
@MikeCluck In the actual code it's not
processbut another long livedEventEmitterthat is passed in the options. I thought about the indirection (only register one handler and execute from a list of handlers) but it does not solve the memory leak problem: in the end there has to be a list of handlers that reference every instance. I looked at WeakMap and WeakSet but they are not enumerable.– Fozi
Nov 15 '18 at 18:14
@Fozi What exactly is the event emitter if it is not
process? What are theLeakyentities, and how many are there (do they accumulate over time or is the number limited)? Also if theLeakyones are supposed to be shorter-lived than the event emitter, when exactly does their live end (i.e. when are they no longer needed)?– Bergi
Nov 15 '18 at 21:01