[[add-process-metadata]]
=== Add process metadata

++++
<titleabbrev>add_process_metadata</titleabbrev>
++++

The `add_process_metadata` processor enriches events with information from running
processes, identified by their process ID (PID).

[source,yaml]
-------------------------------------------------------------------------------
processors:
  - add_process_metadata:
      match_pids: [system.process.ppid]
      target: system.process.parent
-------------------------------------------------------------------------------

The fields added to the event look as follows:
[source,json]
-------------------------------------------------------------------------------
"process": {
  "name":  "systemd",
  "title": "/usr/lib/systemd/systemd --switched-root --system --deserialize 22",
  "exe":   "/usr/lib/systemd/systemd",
  "args":  ["/usr/lib/systemd/systemd", "--switched-root", "--system", "--deserialize", "22"],
  "pid":   1,
  "ppid":  0,
  "start_time": "2018-08-22T08:44:50.684Z",
},
"container": {
  "id": "b5285682fba7449c86452b89a800609440ecc88a7ba5f2d38bedfb85409b30b1"
},
-------------------------------------------------------------------------------

Optionally, the process environment can be included, too:
[source,json]
-------------------------------------------------------------------------------
  ...
  "env": {
    "HOME":       "/",
    "TERM":       "linux",
    "BOOT_IMAGE": "/boot/vmlinuz-4.11.8-300.fc26.x86_64",
    "LANG":       "en_US.UTF-8",
  }
  ...
-------------------------------------------------------------------------------

It has the following settings:

`match_pids`:: List of fields to lookup for a PID. The processor will
search the list sequentially until the field is found in the current event, and
the PID lookup will be applied to the value of this field.

`target`:: (Optional) Destination prefix where the `process` object will be
created. The default is the event's root.

`include_fields`:: (Optional) List of fields to add. By default, the processor
will add all the available fields except `process.env`.

`ignore_missing`:: (Optional) When set to `false`, events that don't contain any
of the fields in match_pids will be discarded and an error will be generated. By
default, this condition is ignored.

`overwrite_keys`:: (Optional) By default, if a target field already exists, it
will not be overwritten and an error will be logged. If `overwrite_keys` is
set to `true`, this condition will be ignored.

`restricted_fields`:: (Optional) By default, the `process.env` field is not
output, to avoid leaking sensitive data. If `restricted_fields` is `true`, the
field will be present in the output.

`host_path`:: (Optional) By default, the `host_path` field is set to the root
directory of the host `/`. This is the path where `/proc` is mounted. For
different runtime configurations of Kubernetes or Docker, the `host_path` can 
be set to overwrite the default.

`cgroup_prefixes`:: (Optional) By default, the `cgroup_prefixes` field is set
to `/kubepods` and `/docker`. This is the prefix where the container ID is
inside cgroup. For different runtime configurations of Kubernetes or Docker,
the `cgroup_prefixes` can be set to overwrite the defaults.

`cgroup_cache_expire_time`:: (Optional) By default, the 
`cgroup_cache_expire_time` is set to 30 seconds. This is the length of time
before cgroup cache elements expire in seconds. It can be set to 0 to disable
the cgroup cache. In some container runtimes technology like runc, the 
container's process is also process in the host kernel, and will be affected by
PID rollover/reuse. The expire time needs to set smaller than the PIDs wrap 
around time to avoid wrong container id.
