java.util.Map is not exported about jmx_exporter

[brian-brazil]

We're going to need a lot more information to know what's going on here. Can you share the code of the mBean in question?

[hagay3]

I'm trying to scrape metrics from cassandra, I tried to catch some specific metric and I saw it's not expose via jmx exporter. Enabled the logging feature for jmx exporter and this error appears for the metric.

  SCHEMA:12:291a4f2c-bc7f-34c1-9eb1-1c0952c3df82
  DC:50:*****
  RACK:30:R1
  RELEASE_VERSION:4:2.1.15.1403
  RPC_ADDRESS:3: **********
  X_11_PADDING:2166926:{"workload":"Cassandra","active":"true","health":1.0}
  SEVERITY:2166924:0.0833333358168602
  NET_VERSION:1:8
  HOST_ID:2:25ebafe4-1a92-4537-912b-0d21a6f18505
  TOKENS:17:<hidden>

Apr 26, 2017 7:36:32 AM io.prometheus.jmx.JmxScraper logScrape
FINE: scrape: 'org.apache.cassandra.net:type=FailureDetector'_'SimpleStates': process
Apr 26, 2017 7:36:32 AM io.prometheus.jmx.JmxScraper logScrape
FINE: scrape: 'org.apache.cassandra.net{type=FailureDetector}': java.util.Map is not exported

[hagay3]

Apparently you skip Map objects :\

    private void processBeanValue(
            String domain,
            LinkedHashMap<String, String> beanProperties,
            LinkedList<String> attrKeys,
            String attrName,
            String attrType,
            String attrDescription,
            Object value) {
        if (value == null) {
            logScrape(domain + beanProperties + attrName, "null");
        } else if (value instanceof Number || value instanceof String || value instanceof Boolean) {
            logScrape(domain + beanProperties + attrName, value.toString());
            this.receiver.recordBean(
                    domain,
                    beanProperties,
                    attrKeys,
                    attrName,
                    attrType,
                    attrDescription,
                    value);
        } else if (value instanceof CompositeData) {
            logScrape(domain + beanProperties + attrName, "compositedata");
            CompositeData composite = (CompositeData) value;
            CompositeType type = composite.getCompositeType();
            attrKeys = new LinkedList<String>(attrKeys);
            attrKeys.add(attrName);
            for(String key : type.keySet()) {
                String typ = type.getType(key).getTypeName();
                Object valu = composite.get(key);
                processBeanValue(
                        domain,
                        beanProperties,
                        attrKeys,
                        key,
                        typ,
                        type.getDescription(),
                        valu);
            }
        } else if (value instanceof TabularData) {
            // I don't pretend to have a good understanding of TabularData.
            // The real world usage doesn't appear to match how they were
            // meant to be used according to the docs. I've only seen them
            // used as 'key' 'value' pairs even when 'value' is itself a
            // CompositeData of multiple values.
            logScrape(domain + beanProperties + attrName, "tabulardata");
            TabularData tds = (TabularData) value;
            TabularType tt = tds.getTabularType();

            List<String> rowKeys = tt.getIndexNames();
            LinkedHashMap<String, String> l2s = new LinkedHashMap<String, String>(beanProperties);

            CompositeType type = tt.getRowType();
            Set<String> valueKeys = new TreeSet<String>(type.keySet());
            valueKeys.removeAll(rowKeys);

            LinkedList<String> extendedAttrKeys = new LinkedList<String>(attrKeys);
            extendedAttrKeys.add(attrName);
            for (Object valu : tds.values()) {
                if (valu instanceof CompositeData) {
                    CompositeData composite = (CompositeData) valu;
                    for (String idx : rowKeys) {
                        l2s.put(idx, composite.get(idx).toString());
                    }
                    for(String valueIdx : valueKeys) {
                        LinkedList<String> attrNames = extendedAttrKeys;
                        String typ = type.getType(valueIdx).getTypeName();
                        String name = valueIdx;
                        if (valueIdx.toLowerCase().equals("value")) {
                            // Skip appending 'value' to the name
                            attrNames = attrKeys;
                            name = attrName;
                        }
                        processBeanValue(
                                domain,
                                l2s,
                                attrNames,
                                name,
                                typ,
                                type.getDescription(),
                                composite.get(valueIdx));
                    }
                } else {
                    logScrape(domain, "not a correct tabulardata format");
                }
            }
        } else if (value.getClass().isArray()) {
            logScrape(domain, "arrays are unsupported");
        } else {
            logScrape(domain + beanProperties, attrType + " is not exported");
        }
    }

[brian-brazil]

JMX is nowhere near standard and we haven't seen one of these before. Can you share the code of the mBean in question?

[hagay3]

I dont have source code for the cassandra mbeans.
What about Map objects ? its should be exposed by jmx exporter?

[brian-brazil]

They're not currently supported.

[hagay3]

I'm willing to add support for this one.

Some suggestions/notes about how-to develop for this repository?

[brian-brazil]

First we need to know what a mBean like this looks like, both in Cassandra and anywhere else one is used.

[obourdon]

I guess this comes from https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/net/MessagingServiceMBean.java

[hagay3]

Just realized prometheous is not meant for exposing arbitrary strings.
its all about integers/double/float
So I will probably fallback to jmxterm and eventually use some meaningful metric.

[brian-brazil]

Okay. Note that we do support extracting strings via the jmx exporter, it's meant for things like version numbers.

[pesimon]

hit the same issue within a custom java service returning java.util.Map from MBean

@brian-brazil Would you consider a PR similar to #348 for adding support to it?

[qixiaobo]

Also met this problem~
SpringBoot also export some map to jmxBean

[qixiaobo]

org.springframework.boot.actuate.endpoint.jmx.DataEndpointMBean