JSON Checks for Heartbeat HTTP Monitors #8667

andrewvc · 2018-10-19T21:43:41Z

Note: This is rebased on top of #8660 since that bug breaks the integration tests here

Add JSON body check support to Heartbeat

This commit adds a new json check for HTTP responses letting users define an arbitrary condition to match against parsed JSON to determine whether an endpoint is up or down.

The nice thing about structured checks like this is that it makes it easy for users to precisely piggy-back on top of existing JSON endpoints, or write their own where a given key/value could indicate the health of an external system. In a sense, it allows users to write a healthcheck endpoint.

An example can be seen below:

heartbeat.monitors:
- type: http
   urls: ["http://localhost:9200"]
   schedule: '@every 10s'
   check.response.json:
     - description: version number should be 6.4.0
       equals.version.number: "6.4.0"

Fixes #7936

houndci-bot · 2018-10-19T21:43:55Z

heartbeat/monitors/active/http/config.go

+	Status      uint16               `config:"status" verify:"min=0, max=699"`
+	RecvHeaders map[string]string    `config:"headers"`
+	RecvBody    []match.Matcher      `config:"body"`
+	RecvJson    []*jsonResponseCheck `config:"json"`


struct field RecvJson should be RecvJSON

houndci-bot · 2018-10-19T21:43:55Z

heartbeat/monitors/active/http/check.go

@@ -115,3 +129,19 @@ func checkBody(body []match.Matcher) RespCheck {
 		return errBodyMismatch
 	}
 }
+
+func checkJson(description string, condition conditions.Condition) RespCheck {


func checkJson should be checkJSON

andrewvc · 2018-10-19T21:45:22Z

Since this includes docs, CCing @dedemorton and @karenzone

andrewvc · 2018-10-19T21:49:00Z

heartbeat/monitors/active/http/check_test.go

@@ -125,3 +128,63 @@ func TestCheckBody(t *testing.T) {
 		})
 	}
 }
+
+func TestCheckJson(t *testing.T) {


These tests are a bit redundant given the python integration tests. However, it's a nicer dev/test cycle when using these. I wrote these first.

I'm +1 to just leave them in, they could be useful in the future.

ruflin · 2018-10-23T07:53:50Z

heartbeat/docs/heartbeat-options.asciidoc

@@ -459,7 +460,11 @@ contains JSON:
      'X-API-Key': '12345-mykey-67890'
  check.response:
    status: 200
-    body: '{"status": "ok"}'
+    json:
+      - description: check status


What is the purpose of the description? logging output?

As this is YAML I would more expect someone that wants to put details about it as a yaml comment.

It's interpolated into the error field in the event when the check fails.

This is important because it means the user can associate a human readable error with the downtime message when they get, say, an SMS.

So, instead of getting "http check for elastic.co/foo failed" they can get one that says JSON body did not match condition '%s' for monitor. Received JSON %+v, where %s is the description.

When using multiple conditions this is even more important since it may not be apparent what caused the failure.

Got it. So the description is sent with every event or just errors (need to check the code).

@ruflin no, it's only sent on error. There are multiple conditions checked, and the first one that fails is the only one that creates an error.

Now that I think about it, that's probably a mistake. We should run all the conditions and list all of the condition failures.

I'll improve the PR by making the error message include a list of error messages. JSON body did not match 2 conditions: "version greater than 1", "name must be valid". Received JSON {...}

ruflin · 2018-10-23T07:54:59Z

@andrewvc Will review this as soon as we get #8660 in and it's rebased on top.

This will probably need a backport to 6.x later on so we get it into 6.6?

andrewvc · 2018-10-23T14:07:31Z

@ruflin thanks for taking a peek. Agree on the backport.

ruflin · 2018-10-25T14:40:09Z

heartbeat/monitors/active/http/simple_transp.go

@@ -147,13 +146,30 @@ func (t *SimpleTransport) writeRequest(conn net.Conn, req *http.Request) error {
 	return err
 }

+// comboConnReadCloser wraps a ReadCloser that is backed by


Will this need a rebase? I remember almost same code went into an other PR.

Yeah, I'll rebase it soon.

ruflin · 2018-10-25T14:41:28Z

heartbeat/monitors/active/http/check_test.go

+	}{
+		{
+			"positive match",
+			"{\"foo\": \"bar\"}",


I would like to see some checks for something like {"a": {"b": "c"}}. How will the config look like if someone wnats to check for a.b=c?

I'd rather avoid adding tests for this sort of behavior. Testing the correctness of conditions seems more like the responsibility of the conditions package.

That said, I'm glad to alter this test to access a nested key instead of a root level one.

Agree it's up to the condition package to work correctly. My worry is that perhaps it doesn't as we will have a problem on the key side + yaml.

I definitively want to know if it works or doesn't. If modifying the test is the best way, lets go for it. We should also adjust it in the system test as I think the actual issue we will hit when we read from Yaml not here in the golang tests.

This fixes an issue where the connection would be closed after only a partial body read. The RoundTripper would close the conn before returning the response which included a partially buffered body. This would actually work for short responses, since the backing bufio would do a partial read, but would fail on all but the shortest responses. Normally connection lifecycle is handled outside the realm of the `RoundTripper`, but for our purposes we don't want to re-use connections. Since it is a requirement that all response bodies be closed, we can piggy-back on top of that to ensure the connection is closed. Fixes elastic#8588

This commit adds a new `json` check for HTTP responses letting users define an arbitrary condition to match against parsed JSON to determine whether an endpoint is up or down. The nice thing about structured checks like this is that it makes it easy for users to precisely piggy-back on top of existing JSON endpoints, or write their own where a given key/value could indicate the health of an external system. In a sense, it allows users to write a healthcheck endpoint. An example can be seen below: ```yaml heartbeat.monitors: - type: http # List or urls to query urls: ["http://localhost:9200"] schedule: '@every 10s' check.response.json: - description: check version condition: equals.version.number: "6.4.0" ```

andrewvc · 2018-10-26T14:50:33Z

@ruflin rebased and pushed with nested keys used in both py and go tests.

ruflin · 2018-10-29T07:44:59Z

heartbeat/monitors/active/http/check.go

+
+		var errorDescs []string
+		for _, compiledCheck := range compiledChecks {
+			//compiledCheck.condition, err = conditions.NewEqualsCondition(map[string]interface{}{"foo.baz": "bar"})


ruflin · 2018-10-29T07:47:56Z

heartbeat/tests/system/test_monitor.py

+                    "check_response_json": [{
+                        "description": "foo equals bar",
+                        "condition": {
+                            "equals": {"foo": {"baz": "bar"}}


What does the YAML output look like here? I assume if you use "foo.baz": "bar" things will not work? What if the response actually has this exact key with a dot inside?

Sorry to keep poking on this one. Agree it's a potential condition issue if it breaks but it shows up here very prominent.

I did some investigation and determined that dotted paths and nested maps are equivalent here due to the use of common.MapStr. This means that you can use either in your condition and it will work.

I think we should move further discussion of this to a separate issue since this has more to do with the beats condition evaluation engine than this specific PR.

ruflin · 2018-10-29T07:48:33Z

Code LGTM except the leftover part (at least I think it's left over)

andrewvc · 2018-10-29T17:53:58Z

@ruflin I removed the comment. What does "Code LGTM" mean here? Am I good to merge? Is the conditions thing a blocker?

ruflin

PR is good to go. My reference was only for the leftover part.

Let's sync up offline quickly so I can explain in more detail the issue around the docs.

On busy CI servers, I suspect some flakiness, as in the case of elastic#8667 (review) is due to the server being temporarily too busy. Let's try lengthening this time to see if that helps.

andrewvc · 2018-11-08T20:29:05Z

jenkins, retest this please

andrewvc · 2018-11-09T17:59:31Z

Build failures are unrelated.

This commit adds a new `json` check for HTTP responses letting users define an arbitrary condition to match against parsed JSON to determine whether an endpoint is up or down. The nice thing about structured checks like this is that it makes it easy for users to precisely piggy-back on top of existing JSON endpoints, or write their own where a given key/value could indicate the health of an external system. In a sense, it allows users to write a healthcheck endpoint. An example can be seen below: ```yaml heartbeat.monitors: - type: http # List or urls to query urls: ["http://localhost:9200"] schedule: '@every 10s' check.response.json: - description: check version condition: equals.version.number: "6.4.0" ``` (cherry picked from commit 22ba375)

praveenkumar466 · 2020-05-26T13:40:41Z

@here : how do we change the monitor.status to partial when there is failure in the validation body

andrewvc added enhancement review Heartbeat labels Oct 19, 2018

andrewvc requested a review from ruflin October 19, 2018 21:43

houndci-bot reviewed Oct 19, 2018

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andrewvc force-pushed the body-json branch from 01a518e to d630e2d Compare October 19, 2018 21:44

andrewvc requested a review from dedemorton October 19, 2018 21:45

andrewvc force-pushed the body-json branch 2 times, most recently from bf34e68 to d447a87 Compare October 19, 2018 21:48

andrewvc commented Oct 19, 2018

View reviewed changes

andrewvc changed the title ~~Body json~~ JSON Checks for Heartbeat HTTP Monitors Oct 19, 2018

ruflin reviewed Oct 23, 2018

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andrewvc added the backport label Oct 23, 2018

ruflin reviewed Oct 25, 2018

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andrewvc added 2 commits October 26, 2018 09:07

andrewvc force-pushed the body-json branch from 07424a4 to 507f678 Compare October 26, 2018 14:49

ruflin reviewed Oct 29, 2018

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Remove accidental comment

1d11a6b

ruflin approved these changes Oct 30, 2018

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andrewvc mentioned this pull request Nov 1, 2018

Lengthen default test timeout to 15 seconds #8896

Closed

andrewvc mentioned this pull request Nov 9, 2018

check.response.body value must not be quoted #7936

Closed

andrewvc merged commit 22ba375 into elastic:master Nov 9, 2018

andrewvc mentioned this pull request Nov 9, 2018

Cherry-pick #8667 to 6.x: JSON Checks for Heartbeat HTTP Monitors #9015

Merged

andrewvc added the v6.6.0 label Nov 9, 2018

andrewvc added the Team:obs-ds-hosted-services Label for the Observability Hosted Services team label Nov 27, 2018

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JSON Checks for Heartbeat HTTP Monitors #8667

JSON Checks for Heartbeat HTTP Monitors #8667

andrewvc commented Oct 19, 2018 •

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JSON Checks for Heartbeat HTTP Monitors #8667

JSON Checks for Heartbeat HTTP Monitors #8667

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