Are you sure that the writer isn't closing the named pipe between writing
JSON objects? If necessary you can check this with strace.
I'm pretty sure you'll get an EOF in the *reader* when the *writer* closes
from their side. You can demonstrate this with the shell:
(In terminal 1)
mkfifo /tmp/fifo
cat /tmp/fifo
(In terminal 2)
cat >/tmp/fifo
abcd
efgh
<< wait a while >>
^D
When you hit ^D in terminal 2, the cat in terminal 1 ends.
The solution (or as you asked, "how to reset this?") is simply to re-open
the fifo for reading.
On Tuesday, 17 October 2023 at 13:40:47 UTC+1 Christopher C wrote:
> I was thinking partial reads could be an issue and the Decoder seemed to
> do the initial checking for me. Would the ReadAll() be able to recover from
> EOF state?
>
> On Tuesday, October 17, 2023 at 4:37:58 AM UTC-4 Volker Dobler wrote:
>
>> Why do you use a json.Decoder? It seems as reading
>> everything (io.ReadAll) until EOF and json.Unmarshal'ling
>> would be a cleaner/simpler solution?
>>
>> V.
>>
>> On Tuesday, 17 October 2023 at 09:10:09 UTC+2 Christopher C wrote:
>>
>>> Hello all!
>>> I'm trying to read json objects from a named pipe. The pipe will be
>>> filled intermittently by bash scripts. After the Decode() of the first
>>> object, any more calls to Decode() will return EOF. This seems proper
>>> since the script has completed, but once it errors with EOF, there doesn't
>>> seem to be a way to read any more.
>>>
>>> Is there a way to 'reset' the decoder so when another script writes to
>>> the pipe it can process the next object, or should I be doing some pipe
>>> length validation before trying to decode?
>>>
>>> Current read code snippet is...
>>>
>>> decoder := json.NewDecoder(fpipe)
>>> for {
>>> err := decoder.Decode(&msg)
>>> if err != nil {
>>> if err == io.EOF {
>>> // how to reset this?
>>> } else {
>>> logger.Fatal(err)
>>> }
>>> } else {
>>> // send out the msg
>>>
>>>
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