[pkg/stanza] Add container operator parser (open-telemetry#32594)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
This PR implements the new container logs parser as it was proposed at
open-telemetry#31959.

**Link to tracking Issue:** <Issue number if applicable>
open-telemetry#31959

**Testing:** <Describe what testing was performed and which tests were
added.>

Added unit tests. Providing manual testing steps as well:

### How to test this manually

1. Using the following config file:
```yaml
receivers:
  filelog:
    start_at: end
    include_file_name: false
    include_file_path: true
    include:
    - /var/log/pods/*/*/*.log
    operators:
      - id: container-parser
        type: container
        output: m1
      - type: move
        id: m1
        from: attributes.k8s.pod.name
        to: attributes.val
      - id: some
        type: add
        field: attributes.key2.key_in
        value: val2

exporters:
  debug:
    verbosity: detailed

service:
  pipelines:
    logs:
      receivers: [filelog]
      exporters: [debug]
      processors: []
```
2. Start the collector:
`./bin/otelcontribcol_linux_amd64 --config
~/otelcol/container_parser/config.yaml`
3. Use the following bash script to create some logs:
```bash
#! /bin/bash

echo '2024-04-13T07:59:37.505201169-05:00 stdout P This is a very very long crio line th' >> /var/log/pods/kube-scheduler-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d3/kube-scheduler43/1.log
echo '{"log":"INFO: log line here","stream":"stdout","time":"2029-03-30T08:31:20.545192187Z"}' >> /var/log/pods/kube-controller-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d6/kube-controller/1.log
echo '2024-04-13T07:59:37.505201169-05:00 stdout F at is awesome! crio is awesome!' >> /var/log/pods/kube-scheduler-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d3/kube-scheduler43/1.log
echo '2021-06-22T10:27:25.813799277Z stdout P some containerd log th' >> /var/log/pods/kube-scheduler-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d3/kube-scheduler44/1.log
echo '{"log":"INFO: another log line here","stream":"stdout","time":"2029-03-30T08:31:20.545192187Z"}' >> /var/log/pods/kube-controller-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d6/kube-controller/1.log
echo '2021-06-22T10:27:25.813799277Z stdout F at is super awesome! Containerd is awesome' >> /var/log/pods/kube-scheduler-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d3/kube-scheduler44/1.log



echo '2024-04-13T07:59:37.505201169-05:00 stdout F standalone crio line which is awesome!' >> /var/log/pods/kube-scheduler-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d3/kube-scheduler43/1.log
echo '2021-06-22T10:27:25.813799277Z stdout F standalone containerd line that is super awesome!' >> /var/log/pods/kube-scheduler-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d3/kube-scheduler44/1.log
```
4. Run the above as a bash script to verify any parallel processing.
Verify that the output is correct.


### Test manually on k8s

1. `make docker-otelcontribcol && docker tag otelcontribcol
otelcontribcol-dev:0.0.1 && kind load docker-image
otelcontribcol-dev:0.0.1`
2. Install using the following helm values file:
```yaml
mode: daemonset
presets:
  logsCollection:
    enabled: true

image:
  repository: otelcontribcol-dev
  tag: "0.0.1"
  pullPolicy: IfNotPresent

command:
  name: otelcontribcol

config:
  exporters:
    debug:
      verbosity: detailed
  receivers:
    filelog:
      start_at: end
      include_file_name: false
      include_file_path: true
      exclude:
        - /var/log/pods/default_daemonset-opentelemetry-collector*_*/opentelemetry-collector/*.log
      include:
        - /var/log/pods/*/*/*.log
      operators:
        - id: container-parser
          type: container
          output: some
        - id: some
          type: add
          field: attributes.key2.key_in
          value: val2


  service:
    pipelines:
      logs:
        receivers: [filelog]
        processors: [batch]
        exporters: [debug]
```
3. Check collector's output to verify the logs are parsed properly:
```console
2024-05-10T07:52:02.307Z	info	LogsExporter	{"kind": "exporter", "data_type": "logs", "name": "debug", "resource logs": 1, "log records": 2}
2024-05-10T07:52:02.307Z	info	ResourceLog #0
Resource SchemaURL: 
ScopeLogs #0
ScopeLogs SchemaURL: 
InstrumentationScope  
LogRecord #0
ObservedTimestamp: 2024-05-10 07:52:02.046236071 +0000 UTC
Timestamp: 2024-05-10 07:52:01.92533954 +0000 UTC
SeverityText: 
SeverityNumber: Unspecified(0)
Body: Str(otel logs at 07:52:01)
Attributes:
     -> log: Map({"iostream":"stdout"})
     -> time: Str(2024-05-10T07:52:01.92533954Z)
     -> k8s: Map({"container":{"name":"busybox","restart_count":"0"},"namespace":{"name":"default"},"pod":{"name":"daemonset-logs-6f6mn","uid":"1069e46b-03b2-4532-a71f-aaec06c0197b"}})
     -> logtag: Str(F)
     -> key2: Map({"key_in":"val2"})
     -> log.file.path: Str(/var/log/pods/default_daemonset-logs-6f6mn_1069e46b-03b2-4532-a71f-aaec06c0197b/busybox/0.log)
Trace ID: 
Span ID: 
Flags: 0
LogRecord #1
ObservedTimestamp: 2024-05-10 07:52:02.046411602 +0000 UTC
Timestamp: 2024-05-10 07:52:02.027386192 +0000 UTC
SeverityText: 
SeverityNumber: Unspecified(0)
Body: Str(otel logs at 07:52:02)
Attributes:
     -> log.file.path: Str(/var/log/pods/default_daemonset-logs-6f6mn_1069e46b-03b2-4532-a71f-aaec06c0197b/busybox/0.log)
     -> time: Str(2024-05-10T07:52:02.027386192Z)
     -> log: Map({"iostream":"stdout"})
     -> logtag: Str(F)
     -> k8s: Map({"container":{"name":"busybox","restart_count":"0"},"namespace":{"name":"default"},"pod":{"name":"daemonset-logs-6f6mn","uid":"1069e46b-03b2-4532-a71f-aaec06c0197b"}})
     -> key2: Map({"key_in":"val2"})
Trace ID: 
Span ID: 
Flags: 0
...
```


**Documentation:** <Describe the documentation added.>  Added

Signed-off-by: ChrsMark <chrismarkou92@gmail.com>

.chloggen/add_container_parser.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: filelogreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add container operator parser
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [31959]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

pkg/stanza/adapter/register.go

@@ -6,6 +6,7 @@ package adapter // import "github.com/open-telemetry/opentelemetry-collector-con
 import (
 	_ "github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/operator/output/file" // Register parsers and transformers for stanza-based log receivers
 	_ "github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/operator/output/stdout"
+	_ "github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/operator/parser/container"
 	_ "github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/operator/parser/csv"
 	_ "github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/operator/parser/json"
 	_ "github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/operator/parser/jsonarray"

pkg/stanza/docs/operators/container.md

@@ -0,0 +1,238 @@
+## `container` operator
+
+The `container` operator parses logs in `docker`, `cri-o` and `containerd` formats.
+
+### Configuration Fields
+
+| Field                        | Default          | Description                                                                                                                                                                                                                           |
+|------------------------------|------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| `id`                         | `container`      | A unique identifier for the operator.                                                                                                                                                                                                 |
+| `format`                     | ``               | The container log format to use if it is known. Users can choose between `docker`, `crio` and `containerd`. If not set, the format will be automatically detected.                                                                    |
+| `add_metadata_from_filepath` | `true`           | Set if k8s metadata should be added from the file path. Requires the `log.file.path` field to be present.                                                                                                                             |
+| `output`                     | Next in pipeline | The connected operator(s) that will receive all outbound entries.                                                                                                                                                                     |
+| `parse_from`                 | `body`           | The [field](../types/field.md) from which the value will be parsed.                                                                                                                                                                   |
+| `parse_to`                   | `attributes`     | The [field](../types/field.md) to which the value will be parsed.                                                                                                                                                                     |
+| `on_error`                   | `send`           | The behavior of the operator if it encounters an error. See [on_error](../types/on_error.md).                                                                                                                                         |
+| `if`                         |                  | An [expression](../types/expression.md) that, when set, will be evaluated to determine whether this operator should be used for the given entry. This allows you to do easy conditional parsing without branching logic with routers. |
+| `severity`                   | `nil`            | An optional [severity](../types/severity.md) block which will parse a severity field before passing the entry to the output operator.                                                                                                 |
+
+
+### Embedded Operations
+
+The `container`  parser can be configured to embed certain operations such as the severity parsing. For more information, see [complex parsers](../types/parsers.md#complex-parsers).
+
+### Add metadata from file path
+
+Requires `include_file_path: true` in order for the `log.file.path` field to be available for the operator.
+If that's not possible, users can disable the metadata addition with `add_metadata_from_filepath: false`.
+A file path like `"/var/log/pods/some-ns_kube-controller-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d6/kube-controller/1.log"`,
+will produce the following k8s metadata:
+
+```json
+{
+  "attributes": {
+    "k8s": {
+      "container": {
+        "name": "kube-controller",
+        "restart_count": "1"
+      }, "pod": {
+        "uid": "49cc7c1fd3702c40b2686ea7486091d6",
+        "name": "kube-controller-kind-control-plane"
+      }, "namespace": {
+        "name": "some-ns"
+      }
+    }
+  }
+}
+```
+
+### Example Configurations:
+
+#### Parse the body as docker container log
+
+Configuration:
+```yaml
+- type: container
+  format: docker
+  add_metadata_from_filepath: true
+```
+
+Note: in this example the `format: docker` is optional since formats can be automatically detected as well.
+      `add_metadata_from_filepath` is true by default as well.
+
+<table>
+<tr><td> Input body </td> <td> Output body</td></tr>
+<tr>
+<td>
+
+```json
+{
+  "timestamp": "",
+  "body": "{\"log\":\"INFO: log line here\",\"stream\":\"stdout\",\"time\":\"2029-03-30T08:31:20.545192187Z\"}",
+  "log.file.path": "/var/log/pods/some_kube-controller-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d6/kube-controller/1.log"
+}
+```
+
+</td>
+<td>
+
+```json
+{
+  "timestamp": "2024-03-30 08:31:20.545192187 +0000 UTC",
+  "body": "log line here",
+  "attributes": {
+    "time": "2024-03-30T08:31:20.545192187Z", 
+    "log.iostream":                "stdout",
+    "k8s.pod.name":                "kube-controller-kind-control-plane",
+    "k8s.pod.uid":                 "49cc7c1fd3702c40b2686ea7486091d6",
+    "k8s.container.name":          "kube-controller",
+    "k8s.container.restart_count": "1",
+    "k8s.namespace.name":          "some",
+    "log.file.path": "/var/log/pods/some_kube-controller-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d6/kube-controller/1.log"
+  }
+}
+```
+
+</td>
+</tr>
+</table>
+
+#### Parse the body as cri-o container log
+
+Configuration:
+```yaml
+- type: container
+```
+
+<table>
+<tr><td> Input body </td> <td> Output body</td></tr>
+<tr>
+<td>
+
+```json
+{
+  "timestamp": "",
+  "body": "2024-04-13T07:59:37.505201169-05:00 stdout F standalone crio line which is awesome",
+  "log.file.path": "/var/log/pods/some_kube-controller-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d6/kube-controller/1.log"
+}
+```
+
+</td>
+<td>
+
+```json
+{
+  "timestamp": "2024-04-13 12:59:37.505201169 +0000 UTC",
+  "body": "standalone crio line which is awesome",
+  "attributes": {
+    "time": "2024-04-13T07:59:37.505201169-05:00",
+    "logtag": "F",
+    "log.iostream":                "stdout",
+    "k8s.pod.name":                "kube-controller-kind-control-plane",
+    "k8s.pod.uid":                 "49cc7c1fd3702c40b2686ea7486091d6",
+    "k8s.container.name":          "kube-controller",
+    "k8s.container.restart_count": "1",
+    "k8s.namespace.name":          "some",
+    "log.file.path": "/var/log/pods/some_kube-controller-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d6/kube-controller/1.log"
+  }
+}
+```
+
+</td>
+</tr>
+</table>
+
+#### Parse the body as containerd container log
+
+Configuration:
+```yaml
+- type: container
+```
+
+<table>
+<tr><td> Input body </td> <td> Output body</td></tr>
+<tr>
+<td>
+
+```json
+{
+  "timestamp": "",
+  "body": "2023-06-22T10:27:25.813799277Z stdout F standalone containerd line that is super awesome",
+  "log.file.path": "/var/log/pods/some_kube-controller-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d6/kube-controller/1.log"
+}
+```
+
+</td>
+<td>
+
+```json
+{
+  "timestamp": "2023-06-22 10:27:25.813799277 +0000 UTC",
+  "body": "standalone containerd line that is super awesome",
+  "attributes": {
+    "time": "2023-06-22T10:27:25.813799277Z",
+    "logtag": "F", 
+    "log.iostream":                "stdout",
+    "k8s.pod.name":                "kube-controller-kind-control-plane",
+    "k8s.pod.uid":                 "49cc7c1fd3702c40b2686ea7486091d6",
+    "k8s.container.name":          "kube-controller",
+    "k8s.container.restart_count": "1",
+    "k8s.namespace.name":          "some",
+    "log.file.path": "/var/log/pods/some_kube-controller-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d6/kube-controller/1.log"
+  }
+}
+```
+
+</td>
+</tr>
+</table>
+
+#### Parse the multiline as containerd container log and recombine into a single one
+
+Configuration:
+```yaml
+- type: container
+```
+
+<table>
+<tr><td> Input body </td> <td> Output body</td></tr>
+<tr>
+<td>
+
+```json
+{
+  "timestamp": "",
+  "body": "2023-06-22T10:27:25.813799277Z stdout P multiline containerd line that i",
+  "log.file.path": "/var/log/pods/some_kube-controller-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d6/kube-controller/1.log"
+},
+{
+  "timestamp": "",
+  "body": "2023-06-22T10:27:25.813799277Z stdout F s super awesomne",
+  "log.file.path": "/var/log/pods/some_kube-controller-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d6/kube-controller/1.log"
+}
+```
+
+</td>
+<td>
+
+```json
+{
+  "timestamp": "2023-06-22 10:27:25.813799277 +0000 UTC",
+  "body": "multiline containerd line that is super awesome",
+  "attributes": {
+    "time": "2023-06-22T10:27:25.813799277Z",
+    "logtag": "F",
+    "log.iostream":                "stdout",
+    "k8s.pod.name":                "kube-controller-kind-control-plane",
+    "k8s.pod.uid":                 "49cc7c1fd3702c40b2686ea7486091d6",
+    "k8s.container.name":          "kube-controller",
+    "k8s.container.restart_count": "1",
+    "k8s.namespace.name":          "some",
+    "log.file.path": "/var/log/pods/some_kube-controller-kind-control-plane_49cc7c1fd3702c40b2686ea7486091d6/kube-controller/1.log"
+  }
+}
+```
+
+</td>
+</tr>
+</table>

pkg/stanza/operator/helper/regexp.go

@@ -0,0 +1,28 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package helper // import "github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/operator/helper"
+
+import (
+	"fmt"
+	"regexp"
+)
+
+func MatchValues(value string, regexp *regexp.Regexp) (map[string]any, error) {
+	matches := regexp.FindStringSubmatch(value)
+	if matches == nil {
+		return nil, fmt.Errorf("regex pattern does not match")
+	}
+
+	parsedValues := map[string]any{}
+	for i, subexp := range regexp.SubexpNames() {
+		if i == 0 {
+			// Skip whole match
+			continue
+		}
+		if subexp != "" {
+			parsedValues[subexp] = matches[i]
+		}
+	}
+	return parsedValues, nil
+}