[Telegraf] Keep getting: Error: unable to parse out as JSON, unexpected end of JSON input

[aschuhl]

I am using the example from json from the readme on data formats: https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_INPUT.md
[
{
"a": 5,
"b": {
"c": 6
},
"ignored": "I'm a string"
}
]

Here is my config file using the tail input:

# Telegraf Configuration
#
# Telegraf is entirely plugin driven. All metrics are gathered from the
# declared inputs, and sent to the declared outputs.
#
# Plugins must be declared in here to be active.
# To deactivate a plugin, comment out the name and any variables.
#
# Use 'telegraf -config telegraf.conf -test' to see what metrics a config
# file would generate.
#
# Environment variables can be used anywhere in this config file, simply prepend
# them with $. For strings the variable must be within quotes (ie, "$STR_VAR"),
# for numbers and booleans they should be plain (ie, $INT_VAR, $BOOL_VAR)

# Global tags can be specified here in key="value" format.
[global_tags]
# dc = "us-east-1" # will tag all metrics with dc=us-east-1
# rack = "1a"
## Environment variables can be used as tags, and throughout the config file
# user = "$USER"

# Configuration for telegraf agent
[agent]
## Default data collection interval for all inputs
interval = "10s"
## Rounds collection interval to 'interval'
## ie, if interval="10s" then always collect on :00, :10, :20, etc.
round_interval = true

## Telegraf will send metrics to outputs in batches of at most
## metric_batch_size metrics.
## This controls the size of writes that Telegraf sends to output plugins.
metric_batch_size = 1000

## For failed writes, telegraf will cache metric_buffer_limit metrics for each
## output, and will flush this buffer on a successful write. Oldest metrics
## are dropped first when this buffer fills.
## This buffer only fills when writes fail to output plugin(s).
metric_buffer_limit = 10000

## Collection jitter is used to jitter the collection by a random amount.
## Each plugin will sleep for a random time within jitter before collecting.
## This can be used to avoid many plugins querying things like sysfs at the
## same time, which can have a measurable effect on the system.
collection_jitter = "0s"

## Default flushing interval for all outputs. You shouldn't set this below
## interval. Maximum flush_interval will be flush_interval + flush_jitter
flush_interval = "10s"
## Jitter the flush interval by a random amount. This is primarily to avoid
## large write spikes for users running a large number of telegraf instances.
## ie, a jitter of 5s and interval 10s means flushes will happen every 10-15s
flush_jitter = "0s"

## By default, precision will be set to the same timestamp order as the
## collection interval, with the maximum being 1s.
## Precision will NOT be used for service inputs, such as logparser and statsd.
## Valid values are "ns", "us" (or "µs"), "ms", "s".
precision = ""

## Logging configuration:
## Run telegraf with debug log messages.
debug = false
## Run telegraf in quiet mode (error log messages only).
quiet = false
## Specify the log file name. The empty string means to log to stderr.
logfile = ""

## Override default hostname, if empty use os.Hostname()
hostname = ""
## If set to true, do no set the "host" tag in the telegraf agent.
omit_hostname = false

###############################################################################
# OUTPUT PLUGINS #
###############################################################################

# Send telegraf metrics to file(s)
[[outputs.file]]
## Files to write to, "stdout" is a specially handled file.
files = ["stdout", "metrics.out"]

## Data format to output.
## Each data format has it's own unique set of configuration options, read
## more about them here:
## https:##github.com#influxdata#telegraf#blob#master#docs#DATA_FORMATS_OUTPUT.md
data_format = "json"

###############################################################################
# PROCESSOR PLUGINS #
###############################################################################

# # Print all metrics that pass through this filter.
# [[processors.printer]]

###############################################################################
# AGGREGATOR PLUGINS #
###############################################################################

# # Keep the aggregate min#max of each metric passing through.
# [[aggregators.minmax]]
# ## General Aggregator Arguments:
# ## The period on which to flush & clear the aggregator.
# period = "30s"
# ## If true, the original metric will be dropped by the
# ## aggregator and will not get sent to the output plugins.
# drop_original = false

###############################################################################
# INPUT PLUGINS #
###############################################################################

###############################################################################
# SERVICE INPUT PLUGINS #
###############################################################################

# Stream a log file, like the tail -f command
[[inputs.tail]]
## files to tail.
## These accept standard unix glob matching rules, but with the addition of
## ** as a "super asterisk". ie:
## "#var#log#**.log" -> recursively find all .log files in #var#log
## "#var#log##.log" -> find all .log files with a parent dir in #var#log
## "#var#log#apache.log" -> just tail the apache log file
##
## See https:##github.com#gobwas#glob for more examples
##
files = ["test.json"]
## Read file from beginning.
from_beginning = true

## Data format to consume.
## Each data format has it's own unique set of configuration options, read
## more about them here:
## https:##github.com#influxdata#telegraf#blob#master#docs#DATA_FORMATS_INPUT.md
data_format = "json"
##tag_keys = [
##]

Here is my output:
./telegraf.exe -config telegraf.conf
2017/01/20 15:39:00 I! Starting Telegraf (version 1.1.2)
2017/01/20 15:39:00 I! Loaded outputs: file
2017/01/20 15:39:00 I! Loaded inputs: inputs.tail
2017/01/20 15:39:00 I! Tags enabled: host=patapl-BLMRQ72
2017/01/20 15:39:00 I! Agent Config: Interval:10s, Quiet:false, Hostname:"patapl-BLMRQ72", Flush Interval:10s
2017/01/20 15:39:00 Seeked test.json - &{Offset:0 Whence:0}
2017/01/20 15:39:00 E! Malformed log line in test.json: [[], Error: unable to parse out as JSON, unexpected end of JSON input
2017/01/20 15:39:00 E! Malformed log line in test.json: [ {], Error: unable to parse out as JSON, unexpected end of JSON input
2017/01/20 15:39:00 E! Malformed log line in test.json: [ "a": 5,], Error: unable to parse out as JSON, invalid character ':' after top-level value
2017/01/20 15:39:00 E! Malformed log line in test.json: [ "b": {], Error: unable to parse out as JSON, invalid character ':' after top-level value
2017/01/20 15:39:00 E! Malformed log line in test.json: [ "c": 6], Error: unable to parse out as JSON, invalid character ':' after top-level value
2017/01/20 15:39:00 E! Malformed log line in test.json: [ },], Error: unable to parse out as JSON, invalid character '}' looking for beginning of value
2017/01/20 15:39:00 E! Malformed log line in test.json: [ "ignored": "I'm a string"], Error: unable to parse out as JSON, invalid character ':' after top-level value
2017/01/20 15:39:00 E! Malformed log line in test.json: [ }], Error: unable to parse out as JSON, invalid character '}' looking for beginning of value

It is valid json though so I'm not sure why it can't parse it.

[rkuchan]

@kostasb - could you take a look at this when you get a chance?

[kostasb]

Hi Anish,

It looks like that JSON string is pretty-printed, meaning that there are newlines in it.
The JSON string should be a one-liner, have you tried the following format?

{"a": 5,"b": {"c": 6},"ignored": "I'm a string"}

Also, please direct your future questions to this repo: https://github.com/influxdata/telegraf/issues or to our mailing list.

Thanks,
Kostas

[kplimack]

@kostasb its been a long time since this issue was addressed, but its still an issue.
can the error message be updated to be helpful?

2017-12-17T18:27:30Z E! Error in plugin [inputs.httpjson]: unable to parse out as JSON, invalid character '<' looking for beginning of value

influxdata/telegraf#3599

[danielnelson]

Closing, we can discuss further on the Telegraf issue tracker.

[dubnemo]

Why is there a requirement for pretty printed JSON, aka one-line JSON? Most integration tools such as Mulesoft will create the new line. Pretty ridiculous requirement.

I am trying to POST via POSTMAN and getting the same error.

[glinton]

@dubnemo can you open a new issue on telegraf with your config and use case. The above issue (multi-line json when using the tail plugin) is only an issue because the tail plugin reads and parses files one line at a time, hence the need for full and parseable (non-prettyprinted) data, regardless of the format.