Pretty print JSON output of Spring Boot Actuator endpoints - json

Question

Spring Boot Actuator provides several endpoints to monitor an application as:
/metrics
/beans
/health
...
Checking the endpoints with:
curl http://localhost:8080/metrics
results in:
{"counter.status.200.env":1,"counter.status.200.health":1,"counter.status.200.info":2,"counter.status.200.metrics":2,"gauge.response.env":5.0,"gauge.response.health":22.0,"gauge.response.info":1.0,"gauge.response.metrics":1.0,"mem":1030144,"mem.free":56118,"processors":8,"uptime":5108095,"instance.uptime":5102906,"heap.committed":1030144,"heap.init":262144,"heap.used":974031,"heap":3728384,"threads.peak":81,"threads.daemon":21,"threads":77,"classes":8854,"classes.loaded":8860,"classes.unloaded":6,"gc.ps_scavenge.count":119,"gc.ps_scavenge.time":7223,"gc.ps_marksweep.count":12,"gc.ps_marksweep.time":17573}
This is fine for machine consumption but hard to read by humans.
I'd like to format (i.e. pretty print) the JSON output of the Spring Boot Actuator endpoints to make them easier to read by operations personel.
Something like:
{
"counter.status.200.env":1,
"counter.status.200.health":1,
"counter.status.200.info":2,
"counter.status.200.metrics":2,
"gauge.response.env":5.0,
"gauge.response.health":22.0,
"gauge.response.info":1.0,
...
}
I tried setting
http.mappers.json-pretty-print=true
but this setting didn't affect the Actuator output.
Is there a configuration to enable pretty print of the Spring Boot Actuator JSON output?
UPDATE:
The official sample works for me.
It's important to follow the comments from #DaveSyer: the property to set is
http.mappers.jsonPrettyPrint=true
Investigation is still under way.
In the meantime I use the the json pretty print command line as workaround:
Install jsonpp (e.g. for OS X):
brew install jsonpp
Then pipe the curl output trough jsonpp which formats the json file on the fly:
curl http://localhost:8080/metrics | jsonpp
Results in:
{
"counter.status.200.env": 1,
"counter.status.200.health": 1,
"counter.status.200.info": 2,
"counter.status.200.metrics": 2,
...
}

Answer 1

As per http://docs.spring.io/spring-boot/docs/current/reference/html/howto-spring-mvc.html#howto-customize-the-jackson-objectmapper, the official way to enable pretty print with Jackson in Spring Boot (1.2.2 at least) is to set the following property:
# Pretty-print JSON responses
spring.jackson.serialization.indent_output=true

Answer 2

For Spring Boot 1.5.1 I have in my YML file:
spring:
jackson:
serialization:
INDENT_OUTPUT: true
#BertrandRenuart answer was the closest, but by IDE did not see indent_output as correct.

Answer 3

The "http.mappers" property works for me but I think you might need it camel cased ("jsonPrettyPrint").

Answer 4

Do the following:
#Configuration
public class JacksonConfig {
#Autowired
private ObjectMapper objectMapper; //reuse the pre-configured mapper
#PostConstruct
public void setup() {
objectMapper.enable(SerializationFeature.INDENT_OUTPUT);
//whatever else you need
}
}
This works because Spring Boot uses an ObjectMapper bean to perform all the JSON related operations.
Note however that this configuration will pretty print all JSON outputs, not just the actuator related stuff.
UPDATE
The answer from #DaveSyer is obviously better! I hadn't found the HttpMapperProperties object which is used to configure Jackson. This is it's Javadoc

Answer 5

Actually I wanted to do the same. But then I asked: why? To debug my service better which comes with a small performance penalty.
Just use a browser extension, like this one :) to get a view like this one

Answer 6

With spring-boot 1.2.6, you need to use:
spring.jackson.serialization.INDENT_OUTPUT=true
From my log when using the old http.mappers.*:
http.mappers.json-pretty-print is deprecated. If you are using Jackson, spring.jackson.serialization.INDENT_OUTPUT=true should be used instead.

Answer 7

I use Python's commonly installed json.tool module:
curl --silent http://localhost:8080/metrics | python -mjson.tool

Answer 8

If you're using gson serialization with Spring, then none of the other answers will work for you. You'll have to use this configuration option:
spring.gson.pretty-printing=true
Confirmed working with Spring Boot as of version 2.0.3.Release.

Answer 9

I use jq for pretty printing JSON as well as filtering it. It's basically sed for JSON. On the mac, it can be installed with homebrew. (https://stedolan.github.io/jq/)
curl http://localhost:8080/metrics | jq

Answer 10

Instead of using curl I like to use httpie as a http command line client:
http http://localhost:8080/metrics
This would already format and syntax highlight the json response without having to pipe the output into another command. Also the command syntax is a bit more human friendly.

Answer 11

Spring Boot Actuator uses its own isolated ObjectMapper instance by default in which indent-output is disabled. To enable pretty-print of actuator output, you must set the following properties:
spring.jackson.serialization.indent-output=true
management.endpoints.jackson.isolated-object-mapper=false

Answer 12

Unfortunately, the application property
spring.jackson.serialization.INDENT_OUTPUT
did not work for me (spring boot versions 1.2.6 to 1.4.0.RELEASE). Instead, in my extension of WebMvcConfigurerAdapter, I've overridden configureMessageConverters() and added my own Jackson2ObjectMapperBuilder:
#Configuration
#EnableWebMvc
public class WebMvcConfig extends WebMvcConfigurerAdapter {
...
private MappingJackson2HttpMessageConverter jacksonMessageConverter() {
Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder()
.featuresToDisable(SerializationFeature.FAIL_ON_EMPTY_BEANS,
SerializationFeature.WRITE_CHAR_ARRAYS_AS_JSON_ARRAYS)
.featuresToEnable(SerializationFeature.INDENT_OUTPUT).modulesToInstall(hibernate4Module());
// can use this instead of featuresToEnable(...)
builder.indentOutput(true);
return new MappingJackson2HttpMessageConverter(builder.build());
}
#Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
converters.add(jacksonMessageConverter());
super.configureMessageConverters(converters);
}
...
}
That seem to do the trick for me on Spring boot 1.4.0.RELEASE and my actuator output is now pretty printed (along with every other json output)

Answer 13

Here is my Emacs function to retrieve Spring Actuator Json from endpoints:
(defvar my/spring-actuator-server-history nil)
(defvar my/spring-actuator-last-server "http://localhost:8080")
(defvar my/spring-actuator-path-history nil)
(defvar my/spring-actuator-path-completion
'("actuator" "auditevents" "autoconfig" "beans" "configprops" "dump" "env" "flyway" "health" "heapdump"
"info" "jolokia" "liquibase" "logfile" "loggers" "mappings" "metrics" "shutdown" "trace")))
(defun my/spring-actuator (server path)
(interactive (list (read-string "Server: " my/spring-actuator-last-server 'my/spring-actuator-server-history)
(completing-read "Path: " my/spring-actuator-path-completion nil nil "" 'my/spring-actuator-path-history)))
(setq my/spring-actuator-last-server server)
(let ( (bufname (format "actuator: %s" path)) )
(when (get-buffer bufname)
(kill-buffer bufname))
(switch-to-buffer (url-retrieve-synchronously (format "%s/%s" server path)))
(rename-buffer bufname)
(goto-char (point-min))
(re-search-forward "^$" nil 'move)
(forward-char)
(delete-region (point-min) (point))
(json-pretty-print-buffer)
(json-mode) ))
If you don't like dependency on external json-mode library replace it with js-mode.

Answer 14

In case somebody with Spring Boot 2 (2.1.1 in my case) stumbles over this question as I did: We faced the same problem, and none of the answers helped for 2.1.1.
So what we did was to replace the existing endpoint (health in our case) with a new one. I described it at the end of this answer. And yes, this limits our solution to this single endpoint, but on the other hand it has the advantage of being able to format the output in any way you want - including pretty print JSON, but also output styled HTML if requested (by a service technician in a browser in our case). Note the produces attribute of #ReadOperation to achieve that.

Answer 15

This is the latest as of 12/27/2022. The below works.
-For application.yml config.
spring:
jackson:
serialization:
indent-output: true
But the above config won't work, if you implement WebMvcConfigurer class. In that case, override like below to make it work.
#Override
public void extendMessageConverters( List<HttpMessageConverter<?>> converters ) {
for ( HttpMessageConverter<?> converter : converters ) {
if ( converter instanceof MappingJackson2HttpMessageConverter) {
MappingJackson2HttpMessageConverter jacksonConverter = (MappingJackson2HttpMessageConverter) converter;
jacksonConverter.setPrettyPrint( true );
}
}
}

Answer 16

this not working
spring.jackson.serialization.INDENT_OUTPUT=true
this is working spring.jackson.serialization.indent-output=true