A custom check for the dd agent to monitor hhvm the PHP JIT interpreter from facebook

To add this to your agent just drop hhvm.py in checks.d folder and hhvm.yaml into conf.dinside your datadog agent config folder. You'll need to update the yaml file by updating the url and the password if necessary (see hhvm-server for the hhvm config).

This is not production tested. For now it only monitors the result from /memory.json and /cheack-healt.

Here are an examples return value:

{
  "Success": 1, 
  "Memory": {
    "Breakdown": {
      "Unknown": 580800246, 
      "Code": {
        "Details": {
          "Bytes": 69296128
        }
      }, 
      "TC/Jit": {
        "Bytes": 213909504, 
        "Details": {
          "code.main": {
            "Used": 34988, 
            "Capacity": 62914560
          },
          "Total Used": 636020, 
          "Total Capacity": 213909504, 
          "code.hot": {
            "Used": 0, 
            "Capacity": 0
          }, 
          "code.cold": {
            "Used": 50129, 
            "Capacity": 25165824
          }, 
          "code.prof": {
            "Used": 292603, 
            "Capacity": 67108864
          }, 
          "data": {
            "Used": 216, 
            "Capacity": 16777216
          }, 
          "code.frozen": {
            "Used": 258084, 
            "Capacity": 41943040
          }
        }
      }, 
      "Static Strings": {
        "Bytes": 2277642, 
        "Details": {
          "Count": 25204
        }
      }
    }, 
    "Process Stats (bytes)": {
      "Shared": 129179648, 
      "VmSize": 866283520, 
      "VmRss": 175067136, 
      "Data": 490242048, 
      "Text(Code)": 69296128
    }
  }
}

{
 "load":0
, "queued":0
, "hhbc-roarena-capac":0
, "tc-hotsize":0
, "tc-size":99282
, "tc-profsize":1266360
, "tc-coldsize":187629
, "tc-frozensize":1064636
, "rds":23600
, "rds-local":88758
, "rds-persistent":63152
, "catch-traces":25565
, "fixups":22256
, "units":82
, "funcs":7592
, "request-count":249
, "single-jit-requests":20
, "prof-funcs":562
, "prof-bc":165213
, "opt-funcs":0
}

It would be great to add the other metrics, and also to avoid craching if the result if not formed exactly as in my example, as it is not really documented.