[receiver/loki] Added new component (#19399)

Co-authored-by: Alex Boten <alex@boten.ca>

.chloggen/add-loki-receiver.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: new_component
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: lokireceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: The Loki receiver implements the [Loki push api](https://grafana.com/docs/loki/latest/clients/promtail/#loki-push-api) as specified [here](https://grafana.com/docs/loki/latest/api/#push-log-entries-to-loki)
+
+# One or more tracking issues related to the change
+issues: [18635]
+
+# (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:

.github/CODEOWNERS

@@ -193,6 +193,7 @@ receiver/k8sobjectsreceiver/                             @open-telemetry/collect
 receiver/kafkametricsreceiver/                           @open-telemetry/collector-contrib-approvers @dmitryax
 receiver/kafkareceiver/                                  @open-telemetry/collector-contrib-approvers @pavolloffay @MovieStoreGuy
 receiver/kubeletstatsreceiver/                           @open-telemetry/collector-contrib-approvers @dmitryax
+receiver/lokireceiver/                                   @open-telemetry/collector-contrib-approvers @mar4uk @kovrus @jpkrohling
 receiver/memcachedreceiver/                              @open-telemetry/collector-contrib-approvers @djaglowski
 receiver/mongodbreceiver/                                @open-telemetry/collector-contrib-approvers @djaglowski @schmikei
 receiver/mongodbatlasreceiver/                           @open-telemetry/collector-contrib-approvers @djaglowski @schmikei

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -182,6 +182,7 @@ body:
       - receiver/kafka
       - receiver/kafkametrics
       - receiver/kubeletstats
+      - receiver/loki
       - receiver/memcached
       - receiver/mongodb
       - receiver/mongodbatlas

.github/ISSUE_TEMPLATE/feature_request.yaml

@@ -176,6 +176,7 @@ body:
       - receiver/kafka
       - receiver/kafkametrics
       - receiver/kubeletstats
+      - receiver/loki
       - receiver/memcached
       - receiver/mongodb
       - receiver/mongodbatlas

.github/ISSUE_TEMPLATE/other.yaml

@@ -176,6 +176,7 @@ body:
       - receiver/kafka
       - receiver/kafkametrics
       - receiver/kubeletstats
+      - receiver/loki
       - receiver/memcached
       - receiver/mongodb
       - receiver/mongodbatlas

.github/dependabot.yml

@@ -877,6 +877,11 @@ updates:
     schedule:
       interval: "weekly"
       day: "wednesday"
+  - package-ecosystem: "gomod"
+    directory: "/receiver/lokireceiver"
+    schedule:
+      interval: "weekly"
+      day: "wednesday"
   - package-ecosystem: "gomod"
     directory: "/receiver/memcachedreceiver"
     schedule:
@@ -1097,8 +1102,3 @@ updates:
     schedule:
       interval: "weekly"
       day: "wednesday"
-  - package-ecosystem: "gomod"
-    directory: "/testbed"
-    schedule:
-      interval: "weekly"
-      day: "wednesday"

receiver/lokireceiver/Makefile

@@ -0,0 +1 @@
+include ../../Makefile.Common

receiver/lokireceiver/README.md

@@ -0,0 +1,32 @@
+# Loki Receiver
+
+| Status                   |               |
+| ------------------------ |---------------|
+| Stability                | [development] |
+| Supported pipeline types | logs          |
+| Distributions            | [contrib]     |
+
+The Loki receiver implements the [Loki push api](https://grafana.com/docs/loki/latest/clients/promtail/#loki-push-api) as specified [here](https://grafana.com/docs/loki/latest/api/#push-log-entries-to-loki). 
+It allows Promtail instances to specify the open telemetry collector as their lokiAddress.
+
+This receiver runs HTTP and GRPC servers to ingest log entries in Loki format.
+
+## Getting Started
+
+The settings are:
+
+- `endpoint` (required, default = 0.0.0.0:3500 for grpc protocol, 0.0.0.0:3600 http protocol): host:port to which the receiver is going to receive data.
+- `use_incoming_timestamp` (optional, default = false) if set `true` the timestamp from Loki log entry is used
+
+Example:
+```yaml
+receivers:
+  loki:
+    protocols:
+      http:
+      grpc:
+    use_incoming_timestamp: true
+```
+
+[development]:https://github.com/open-telemetry/opentelemetry-collector#development
+[contrib]:https://github.com/open-telemetry/opentelemetry-collector-releases/tree/main/distributions/otelcol-contrib

receiver/lokireceiver/config.go

@@ -0,0 +1,72 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package lokireceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/lokireceiver"
+
+import (
+	"errors"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config/configgrpc"
+	"go.opentelemetry.io/collector/config/confighttp"
+	"go.opentelemetry.io/collector/confmap"
+)
+
+const (
+	// Protocol values.
+	protoGRPC = "protocols::grpc"
+	protoHTTP = "protocols::http"
+)
+
+// Protocols is the configuration for the supported protocols.
+type Protocols struct {
+	GRPC *configgrpc.GRPCServerSettings `mapstructure:"grpc"`
+	HTTP *confighttp.HTTPServerSettings `mapstructure:"http"`
+}
+
+// Config defines configuration for the lokireceiver receiver.
+type Config struct {
+	// Protocols is the configuration for the supported protocols, currently gRPC and HTTP (Proto and JSON).
+	Protocols     `mapstructure:"protocols"`
+	KeepTimestamp bool `mapstructure:"use_incoming_timestamp"`
+}
+
+var _ component.Config = (*Config)(nil)
+var _ confmap.Unmarshaler = (*Config)(nil)
+
+// Validate checks the receiver configuration is valid
+func (cfg *Config) Validate() error {
+	if cfg.GRPC == nil && cfg.HTTP == nil {
+		return errors.New("must specify at least one protocol when using the Loki receiver")
+	}
+	return nil
+}
+
+// Unmarshal a confmap.Conf into the config struct.
+func (cfg *Config) Unmarshal(conf *confmap.Conf) error {
+	err := conf.Unmarshal(cfg, confmap.WithErrorUnused())
+	if err != nil {
+		return err
+	}
+
+	if !conf.IsSet(protoGRPC) {
+		cfg.GRPC = nil
+	}
+
+	if !conf.IsSet(protoHTTP) {
+		cfg.HTTP = nil
+	}
+
+	return nil
+}

receiver/lokireceiver/config_test.go

@@ -0,0 +1,143 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package lokireceiver
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config/configgrpc"
+	"go.opentelemetry.io/collector/config/confighttp"
+	"go.opentelemetry.io/collector/config/confignet"
+	"go.opentelemetry.io/collector/confmap/confmaptest"
+)
+
+func TestLoadConfig(t *testing.T) {
+	t.Parallel()
+
+	cm, err := confmaptest.LoadConf(filepath.Join("testdata", "config.yaml"))
+	require.NoError(t, err)
+
+	tests := []struct {
+		id       component.ID
+		expected component.Config
+	}{
+		{
+			id: component.NewIDWithName(typeStr, "defaults"),
+			expected: &Config{
+				Protocols: Protocols{
+					GRPC: &configgrpc.GRPCServerSettings{
+						NetAddr: confignet.NetAddr{
+							Endpoint:  "0.0.0.0:3600",
+							Transport: "tcp",
+						},
+					},
+					HTTP: &confighttp.HTTPServerSettings{
+						Endpoint: "0.0.0.0:3500",
+					},
+				},
+			},
+		},
+		{
+			id: component.NewIDWithName(typeStr, "mixed"),
+			expected: &Config{
+				Protocols: Protocols{
+					GRPC: &configgrpc.GRPCServerSettings{
+						NetAddr: confignet.NetAddr{
+							Endpoint:  "localhost:4600",
+							Transport: "tcp",
+						},
+					},
+					HTTP: &confighttp.HTTPServerSettings{
+						Endpoint: "localhost:4500",
+					},
+				},
+				KeepTimestamp: true,
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.id.String(), func(t *testing.T) {
+			factory := NewFactory()
+			cfg := factory.CreateDefaultConfig()
+
+			sub, err := cm.Sub(tt.id.String())
+			require.NoError(t, err)
+			require.NoError(t, component.UnmarshalConfig(sub, cfg))
+
+			assert.NoError(t, component.ValidateConfig(cfg))
+			assert.Equal(t, tt.expected, cfg)
+		})
+	}
+}
+
+func TestInvalidConfig(t *testing.T) {
+	cm, err := confmaptest.LoadConf(filepath.Join("testdata", "config.yaml"))
+	require.NoError(t, err)
+
+	tests := []struct {
+		id  component.ID
+		err string
+	}{
+		{
+			id:  component.NewIDWithName(typeStr, "empty"),
+			err: "must specify at least one protocol when using the Loki receiver",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.id.String(), func(t *testing.T) {
+			factory := NewFactory()
+			cfg := factory.CreateDefaultConfig()
+
+			sub, err := cm.Sub(tt.id.String())
+			require.NoError(t, err)
+			require.NoError(t, component.UnmarshalConfig(sub, cfg))
+
+			err = component.ValidateConfig(cfg)
+			assert.Contains(t, err.Error(), tt.err)
+		})
+	}
+}
+
+func TestConfigWithUnknownKeysConfig(t *testing.T) {
+	cm, err := confmaptest.LoadConf(filepath.Join("testdata", "config.yaml"))
+	require.NoError(t, err)
+
+	tests := []struct {
+		id  component.ID
+		err string
+	}{
+		{
+			id:  component.NewIDWithName(typeStr, "extra_keys"),
+			err: "'' has invalid keys: foo",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.id.String(), func(t *testing.T) {
+			factory := NewFactory()
+			cfg := factory.CreateDefaultConfig()
+
+			sub, err := cm.Sub(tt.id.String())
+			require.NoError(t, err)
+			assert.Contains(t, component.UnmarshalConfig(sub, cfg).Error(), tt.err)
+		})
+	}
+}

receiver/lokireceiver/factory.go

@@ -0,0 +1,71 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package lokireceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/lokireceiver"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config/configgrpc"
+	"go.opentelemetry.io/collector/config/confighttp"
+	"go.opentelemetry.io/collector/config/confignet"
+	"go.opentelemetry.io/collector/consumer"
+	"go.opentelemetry.io/collector/receiver"
+)
+
+const (
+	// The value of "type" key in configuration.
+	typeStr = "loki"
+	// The stability level of the receiver.
+	stability = component.StabilityLevelDevelopment
+
+	defaultGRPCBindEndpoint = "0.0.0.0:3600"
+	defaultHTTPBindEndpoint = "0.0.0.0:3500"
+)
+
+// NewFactory return a new receiver.Factory for loki receiver.
+func NewFactory() receiver.Factory {
+	return receiver.NewFactory(
+		typeStr,
+		createDefaultConfig,
+		receiver.WithLogs(createLogsReceiver, stability))
+}
+
+func createDefaultConfig() component.Config {
+	return &Config{
+		Protocols: Protocols{
+			GRPC: &configgrpc.GRPCServerSettings{
+				NetAddr: confignet.NetAddr{
+					Endpoint:  defaultGRPCBindEndpoint,
+					Transport: "tcp",
+				},
+			},
+			HTTP: &confighttp.HTTPServerSettings{
+				Endpoint: defaultHTTPBindEndpoint,
+			},
+		},
+	}
+}
+
+func createLogsReceiver(
+	_ context.Context,
+	settings receiver.CreateSettings,
+	cfg component.Config,
+	consumer consumer.Logs,
+) (receiver.Logs, error) {
+
+	rCfg := cfg.(*Config)
+	return newLokiReceiver(rCfg, consumer, settings)
+}