Function call failed: Server error

Troubleshooting
1

Hi Particle,

I am calling an IoT function to return some value but I’m getting “Function call failed: Server error” problem.

I was using particle cli version 1.30.x and I just updated to 1.31.0 but I am still getting this problem. I tried on an old computer with 1.23.0 and it worked fine.

Thank you very much!

2

Honestly, I just want know how could I downgrade at this stage because I am experiencing other issues every time I updates to a new version. Any way I can do that? Currently my most favorite version is 1.21.0.

Thank you!

3

There should not be any benefit in using an old CLI.

What exactly did you do that failed?
How does the called function look in your firmware?
It’s just a guess, but it may be that the older CLI used a slightly longer timeout for a Particle.function() call to return, but since a Particle.function() handler should usually return in less than a second the possible difference in timeout should not play any role.

4

I am trying to take a sensor reading in that function call and it has i2c communications in it. Yes It might take a while to get the return value.

Does it have anything to do with the parameter string the function takes? Here is what I’m experiencing:
particle call PARTICLE_ID dbg sensor_reading
=> server error
particle call PARTICLE_ID dbg status
=> 1 (which means fine.)

So is the underscore not acceptable?

5

That's probably the issue.
The underscore in the command payload shouldn't play any role.

I guess dbg status returns a lot quicker than dbg sensor_reading does.

I previously have proposed an option to mark a Particle.function() as "slow returning" having the cloud extend the timeout period for it (e.g. by providing a timeout parameter for the expected time it would usually take), but that hasn't been considered by Particle yet.

Till then (if ever) I have my functions only set a flag and return immediately.
The flag tells loop() to perform the action and set a Particle.variable() to "return" the result.

6

New input! I found that whenever a 0 value is returned, I got this server error. For example, my sensor reading function returns something non-zero, I can get it right.

I am wondering if Particle is using 0 as their error code for server error??

7

That shouldn't be, but I've just tested and you seem to be right - I think that's not intended.

Have you tried Particle Console | Build your connected product to trigger your function?

8

Yes I was going to but because we have a lot of units online and there is no filtering or searching function on the /device page, it was hard for me to find my testing device.