Thanks Robert, this is what I ended up doing. I wouldnt say it was trivial though :-) https://github.com/Velocidex/json Thanks and sorry for hijacking this thread. Maybe a suggestion - if users are not expected to change time.Local maybe it should be made private or at least wording in the module should not say that clients are allowed to change it. Having a public variable invites users to expect that changing it is acceptable and only after getting hit by the race detector and spending a huge amount of time figuring out the details it becomes apparent that it should not be changed ThanksMike On Fri, 2020-07-24 at 11:51 -0500, Robert Engels wrote: > Yea, it is strange the the Json encoder api doesn’t allow the caller > to provide a mashaller for any type. It would be trivial to change > the code to do so. > That being said I’m sure you can find custom json libs on the web > that will do this. Or fork it yourself - it is not a lot of code. > > On Jul 24, 2020, at 11:15 AM, Mike Cohen <[email protected]> > > wrote: > > > > To be clear, the time.MarshalJSON() function produces valid RFC > > 3339 timestamps which allow arbitrary timezones. This means that > > local time offset is used in the string representation. Although > > all representations are technically equivalent their string form is > > not so we need to do special parsing to compare them (and users get > > really confused as well). > > Here is an example - https://play.golang.org/p/hELVEI1tGJd > > when I run it I get {"A":6,"B":"2009-11-11T10:00:00+11:00"} for > > Australia time, but {"A":6,"B":"2009-11-10T18:00:00-05:00"} for > > America/New_York. > > I am aware I can use the .In() method to cast the time.Time object > > into different timezone but this is the whole issue - I need to > > search through all the struct fields, expand slices, recurse > > through maps etc just to find any time.Time objects and change them > > **before** I call json.Marshal(). > > I usually get the times from a struct in another library so I have > > no control over how these times are made for example consider this > > https://play.golang.org/p/HmGREBF2Hbd > > where I call an out of tree library to build a struct then just > > want to dump it - I have no control over the encoding. > > I think this is a actually a limitation in the json strategy of > > encoding based only on types and not on context. The TZ issue is > > just a manifestation of that - even if there was a safe way to set > > TZ in a running program, in a multithreaded program all json > > encoders would be forced to use the same local TZ because encoding > > goes with type and not with context. > > Thanks.Mike > > > > On Thu, 2020-07-23 at 20:02 -0700, Ian Lance Taylor wrote: > > > On Thu, Jul 23, 2020 at 5:13 PM Michael Cohen <[email protected] > > > > wrote: > > > > Thanks Ian, this does not work as I mentioned because there is > > > > no way to guarantee that my init function will run before any > > > > of my libraries creating a time object (which many do as they > > > > start various background tasks). > > > > Doing what you say is fragile because even if it appears to > > > > work, one day I might link a library and it will mysteriously > > > > break randomly (this happened to us previously). > > > > Is this a bug in the time package? Or simply a bug or design > > > > shortfall in the json package? One way I thought to fix this > > > > issue is to simply fork the json encoder and handle time.Time > > > > structs specifically, but this obviously does not scale to eg > > > > yaml encoders etc. > > > > > > I don't think it's a shortfall in the encoding/json package as > > > such,as that package knows nothing about times. It's the time > > > package thatimplements an UnmarshalJSON. Looking at that method, > > > I'm a littlesurprised at what you describe, since it just uses > > > the timezone in theJSON string. It doesn't use the local > > > timezone as far as I can see.Can you show a small program that > > > demonstrates the problem? > > > Ian > > -- > > <velo_black_small_full_res.png>Mike Cohen > > Digital Paleontologist > > > > Velocidex Enterprises > > https://www.velocidex.com > > > > +61.470238491 > > > > > > > > > > > > -- Mike Cohen Digital Paleontologist
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