Metrics API

Introduction

Orion implements a REST-based API that can be used to get relevant operational metrics. This API is a complement to the statistics API which is more low-level and aimed at debugging.

Note that this API can be switched off to avoid overhead (gathering of metrics is a bit costly, as system calls and semaphores are involved) using the -disableMetrics CLI parameter.

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Operations

Get metrics

GET /admin/metrics

The response payload is a multi-level JSON tree storing the information in an structured way. It is based on the service and subservice (sometimes refered to as "service path"). At any point of the tree, the value of a key could be {} to mean that there isn't actual information associated to that key.

At the first level there are two keys: services and sum. In sequence, services value is an object whose keys are service names and whose values are objects with information about the corresponding service. The sum value is an object with information for the aggregated information for all services.

{
  "services": {
    "service1": <service 1 info>,
    "service2": <service 2 info>,
    ...
    "serviceN": <service N info>
  }
  "sum": <aggregated info for all services>
}

Regarding service information objects, they use two keys: subservs and sum. In sequence, subservs value is an object whose keys are subservice names and whose values are objects with information about the corresponding subservice. The sum value is an object with information for the aggregated information for all subservices in the given services.

{
  "subservs": {
    "subservice1": <subservice 1 info>,
    "subservice2": <subservice 2 info>,
    ...
    "subserviceN": <subservice N info>
  }
  "sum": <aggregated info for all subservice in the given service>
}

Subservice names in the above structure are shown without the initial slash. E.g. if the subservice name is (as used in the Fiware-ServicePath header) /gardens then the key used for it would be gardens (without /). Others slashes apart from the initial one are not removed, e.g. /gardens/north uses the key gardens/north.

Regarding subservice information object, keys are the name of the different metrics.

{
  "metric1": <metric 1>,
  "metric2": <metric 2>,
  ...
  "metricN": <metric N>
}

The list of metrics is provided in metrics section.

Some additional remarks:

  • Requests corresponding to invalid services or subservices (i.e. the ones that don't follow the syntax rules described here and here) are not included in the payload (i.e. their associated metrics are just ignored).
  • The default service uses default-service as service key. Note that it cannot collide with regular services as the - character is not allowed in regular services.
  • The root subservice (/) uses root-subserv as subservice key. Note that it cannot collide with regular subservices as the - character is not allowed in regular subservices.
  • Requests using an enumeration of subservices (e.g. Fiware-ServicePath: /A, /B) are associated to the first element of the list, i.e. A.
  • Requests using "recursive subservice" (e.g. Fiware-ServicePath: /A/#) are associated to the subservice without considering recursivity, i.e. A.

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Reset metrics

DELETE /admin/metrics

This operation resets all metrics, as if Orion would had just been started.

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Get and reset

GET /admin/metrics?reset=true

This operation (in fact, a variant of get metrics) get results and, at the same time in an atomical way, resets metrics.

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Metrics

  • incomingTransactions: number of requests consumed by Orion. All kind of transactions (no matter if they are ok transactions or error transactions) count for this metric.
  • incomingTransactionRequestSize: total size (bytes) in requests associated to incoming transactions ("in" from the point of view of Orion). All kind of transactions (no matter if they are ok transactions or error transactions) count for this metric.
  • incomingTransactionResponseSize: total size (bytes) in responses associated to incoming transactions ("out" from the point of view of Orion). All kind of transactions (no matter if they are ok transactions or error transactions) count for this metric.
  • incomingTransactionErrors: number of incoming transactions resulting in error.
  • serviceTime: average time to serve a transaction. All kind of transactions (no matter if they are ok transactions or error transactions) count for this metric.
  • outgoingTransactions: number of requests sent by Orion (both notifications and forward requests to CPrs). All kind of transactions (no matter if they are ok transactions or error transactions) count for this metric.
  • outgoingTransactionRequestSize: total size (bytes) in requests associated to outgoing transactions ("out" from the point of view of Orion). All kind of transactions (no matter if they are ok transactions or error transactions) count for this metric.
  • outgoingTransactionResponseSize: total size (bytes) in responses associated to outgoing transactions ("in" from the point of view of Orion). All kind of transactions (no matter if they are ok transactions or error transactions) count for this metric.
  • outgoingTransactionErrors: number of outgoing transactions resulting in error.

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