OpenTelemetry Input Plugin (#9077)

docs/LICENSE_OF_DEPENDENCIES.md

@@ -105,6 +105,9 @@ following works:
 - github.com/hashicorp/golang-lru [Mozilla Public License 2.0](https://github.com/hashicorp/golang-lru/blob/master/LICENSE)
 - github.com/hashicorp/serf [Mozilla Public License 2.0](https://github.com/hashicorp/serf/blob/master/LICENSE)
 - github.com/influxdata/go-syslog [MIT License](https://github.com/influxdata/go-syslog/blob/develop/LICENSE)
+- github.com/influxdata/influxdb-observability/common [MIT License](https://github.com/influxdata/influxdb-observability/blob/main/LICENSE)
+- github.com/influxdata/influxdb-observability/otel2influx [MIT License](https://github.com/influxdata/influxdb-observability/blob/main/LICENSE)
+- github.com/influxdata/influxdb-observability/otlp [MIT License](https://github.com/influxdata/influxdb-observability/blob/main/LICENSE)
 - github.com/influxdata/tail [MIT License](https://github.com/influxdata/tail/blob/master/LICENSE.txt)
 - github.com/influxdata/toml [MIT License](https://github.com/influxdata/toml/blob/master/LICENSE)
 - github.com/influxdata/wlog [MIT License](https://github.com/influxdata/wlog/blob/master/LICENSE)

go.mod

@@ -73,6 +73,9 @@ require (
 	github.com/hashicorp/consul/api v1.6.0
 	github.com/hashicorp/go-msgpack v0.5.5 // indirect
 	github.com/influxdata/go-syslog/v2 v2.0.1
+	github.com/influxdata/influxdb-observability/common v0.0.0-20210429174543-86ae73cafd31
+	github.com/influxdata/influxdb-observability/otel2influx v0.0.0-20210429174543-86ae73cafd31
+	github.com/influxdata/influxdb-observability/otlp v0.0.0-20210429174543-86ae73cafd31
 	github.com/influxdata/tail v1.0.1-0.20200707181643-03a791b270e4
 	github.com/influxdata/toml v0.0.0-20190415235208-270119a8ce65
 	github.com/influxdata/wlog v0.0.0-20160411224016-7c63b0a71ef8
@@ -137,7 +140,7 @@ require (
 	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20200205215550-e35592f146e4
 	google.golang.org/api v0.29.0
 	google.golang.org/genproto v0.0.0-20200815001618-f69a88009b70
-	google.golang.org/grpc v1.33.1
+	google.golang.org/grpc v1.37.0
 	gopkg.in/djherbis/times.v1 v1.2.0
 	gopkg.in/fatih/pool.v2 v2.0.0 // indirect
 	gopkg.in/gorethink/gorethink.v3 v3.0.5

go.sum

@@ -235,6 +235,7 @@ github.com/cisco-ie/nx-telemetry-proto v0.0.0-20190531143454-82441e232cf6/go.mod
 github.com/clbanning/x2j v0.0.0-20191024224557-825249438eec/go.mod h1:jMjuTZXRI4dUb/I5gc9Hdhagfvm9+RyrPryS/auMzxE=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
 github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
+github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
 github.com/cockroachdb/apd v1.1.0 h1:3LFP3629v+1aKXU5Q37mxmRxX/pIu1nijXydLShEq5I=
 github.com/cockroachdb/apd v1.1.0/go.mod h1:8Sl8LxpKi29FqWXR16WEFZRNSz3SoPzUzeMeY4+DwBQ=
 github.com/cockroachdb/datadriven v0.0.0-20190809214429-80d97fb3cbaa/go.mod h1:zn76sxSg3SzpJ0PPJaLDCu+Bu0Lg3sKTORVIj19EIF8=
@@ -315,6 +316,7 @@ github.com/envoyproxy/go-control-plane v0.6.9/go.mod h1:SBwIajubJHhxtWwsL9s8ss4s
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
+github.com/envoyproxy/go-control-plane v0.9.9-0.20210217033140-668b12f5399d/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
 github.com/evanphx/json-patch v0.0.0-20200808040245-162e5629780b/go.mod h1:NAJj0yf/KaRKURN6nyi7A9IZydMivZEm9oQLWNjfKDc=
 github.com/evanphx/json-patch v4.2.0+incompatible/go.mod h1:50XU6AFN0ol/bzJsmQLiYLvXMP4fmwYFNcr97nuDLSk=
@@ -526,6 +528,7 @@ github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvq
 github.com/golang/protobuf v1.4.1/go.mod h1:U8fpvMrcmy5pZrNK1lt4xCsGvpyWQ/VVv6QDs8UjoX8=
 github.com/golang/protobuf v1.4.2/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
 github.com/golang/protobuf v1.4.3/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
+github.com/golang/protobuf v1.4.3/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
 github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
 github.com/golang/protobuf v1.5.1 h1:jAbXjIeW2ZSW2AwFxlGTDoc2CjI2XujLkV3ArsZFCvc=
 github.com/golang/protobuf v1.5.1/go.mod h1:DopwsBzvsk0Fs44TXzsVbJyPhcCPeIwnvohx4u74HPM=
@@ -667,6 +670,14 @@ github.com/influxdata/flux v0.65.0/go.mod h1:BwN2XG2lMszOoquQaFdPET8FRQfrXiZsWmc
 github.com/influxdata/go-syslog/v2 v2.0.1 h1:l44S4l4Q8MhGQcoOxJpbo+QQYxJqp0vdgIVHh4+DO0s=
 github.com/influxdata/go-syslog/v2 v2.0.1/go.mod h1:hjvie1UTaD5E1fTnDmxaCw8RRDrT4Ve+XHr5O2dKSCo=
 github.com/influxdata/influxdb v1.8.2/go.mod h1:SIzcnsjaHRFpmlxpJ4S3NT64qtEKYweNTUMb/vh0OMQ=
+github.com/influxdata/influxdb-observability/common v0.0.0-20210428231528-a010f53e3e02/go.mod h1:PMngVYsW4uwtzIVmj0ZfLL9UIOwo7Vs+09QHkoYMZv8=
+github.com/influxdata/influxdb-observability/common v0.0.0-20210429174543-86ae73cafd31 h1:pfWcpiOrWLJvicIpCiFR8vqrkVbAuKUttWvQDmSlfUM=
+github.com/influxdata/influxdb-observability/common v0.0.0-20210429174543-86ae73cafd31/go.mod h1:PMngVYsW4uwtzIVmj0ZfLL9UIOwo7Vs+09QHkoYMZv8=
+github.com/influxdata/influxdb-observability/otel2influx v0.0.0-20210429174543-86ae73cafd31 h1:uiRNaaczvfx837c6OSH9Q6H4td1cWnR9X0pveHTHeYs=
+github.com/influxdata/influxdb-observability/otel2influx v0.0.0-20210429174543-86ae73cafd31/go.mod h1:43guzIbK1oO/UMBuMCqG++LHZqLhMbWxqU4H1Lgpf28=
+github.com/influxdata/influxdb-observability/otlp v0.0.0-20210428231528-a010f53e3e02/go.mod h1:J2N8KOAXSXgDhLjYWvjbxPhrgq3nVQ/npzW8l8T77Qo=
+github.com/influxdata/influxdb-observability/otlp v0.0.0-20210429174543-86ae73cafd31 h1:Cf6WCNdgyxWv3x3uMehlexHAkWO3AZTAv5Q2yo0WQ0s=
+github.com/influxdata/influxdb-observability/otlp v0.0.0-20210429174543-86ae73cafd31/go.mod h1:23SLY21Ag84PC0TbvVhdKoOVvrQF6nq5j5sFOW09ZBU=
 github.com/influxdata/influxdb1-client v0.0.0-20191209144304-8bf82d3c094d/go.mod h1:qj24IKcXYK6Iy9ceXlo3Tc+vtHo9lIhSX5JddghvEPo=
 github.com/influxdata/influxql v1.1.0/go.mod h1:KpVI7okXjK6PRi3Z5B+mtKZli+R1DnZgb3N+tzevNgo=
 github.com/influxdata/line-protocol v0.0.0-20180522152040-32c6aa80de5e/go.mod h1:4kt73NQhadE3daL3WhR5EJ/J2ocX0PZzwxQ0gXJ7oFE=
@@ -1452,6 +1463,7 @@ golang.org/x/tools v0.0.0-20200619180055-7c47624df98f/go.mod h1:EkVYQZoAsY45+roY
 golang.org/x/tools v0.0.0-20200822203824-307de81be3f4/go.mod h1:njjCfa9FT2d7l9Bc6FUM5FLjQPp3cFF28FI3qnDFljA=
 golang.org/x/tools v0.0.0-20201022035929-9cf592e881e9/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.0.0-20210106214847-113979e3529a/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
+golang.org/x/tools v0.0.0-20210106214847-113979e3529a/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.1.0 h1:po9/4sTYwZU9lPhi1tOrb4hCv3qrhiQ77LZfGa2OjwY=
 golang.org/x/tools v0.1.0/go.mod h1:xkSsbof2nBLbhDlRMhhhyNLN/zl3eTqcnHD5viDpcZ0=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
@@ -1518,6 +1530,7 @@ google.golang.org/genproto v0.0.0-20200513103714-09dca8ec2884/go.mod h1:55QSHmfG
 google.golang.org/genproto v0.0.0-20200513103714-09dca8ec2884/go.mod h1:55QSHmfGQM9UVYDPBsyGGes0y52j32PQ3BqQfXhyH3c=
 google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013/go.mod h1:NbSheEEYHJ7i3ixzK3sjbqSGDJWnxyFXZblF3eUsNvo=
 google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013/go.mod h1:NbSheEEYHJ7i3ixzK3sjbqSGDJWnxyFXZblF3eUsNvo=
+google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013/go.mod h1:NbSheEEYHJ7i3ixzK3sjbqSGDJWnxyFXZblF3eUsNvo=
 google.golang.org/genproto v0.0.0-20200815001618-f69a88009b70 h1:wboULUXGF3c5qdUnKp+6gLAccE6PRpa/czkYvQ4UXv8=
 google.golang.org/genproto v0.0.0-20200815001618-f69a88009b70/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
 google.golang.org/grpc v1.17.0/go.mod h1:6QZJwpn2B+Zp71q/5VxRsJ6NXXVCE5NRUHRo+f3cWCs=
@@ -1535,8 +1548,9 @@ google.golang.org/grpc v1.27.0/go.mod h1:qbnxyOmOxrQa7FizSgH+ReBfzJrCY1pSN7KXBS8
 google.golang.org/grpc v1.27.1/go.mod h1:qbnxyOmOxrQa7FizSgH+ReBfzJrCY1pSN7KXBS8abTk=
 google.golang.org/grpc v1.28.0/go.mod h1:rpkK4SK4GF4Ach/+MFLZUBavHOvF2JJB5uozKKal+60=
 google.golang.org/grpc v1.29.1/go.mod h1:itym6AZVZYACWQqET3MqgPpjcuV5QH3BxFS3IjizoKk=
-google.golang.org/grpc v1.33.1 h1:DGeFlSan2f+WEtCERJ4J9GJWk15TxUi8QGagfI87Xyc=
 google.golang.org/grpc v1.33.1/go.mod h1:fr5YgcSWrqhRRxogOsw7RzIpsmvOZ6IcH4kBYTpR3n0=
+google.golang.org/grpc v1.37.0 h1:uSZWeQJX5j11bIQ4AJoj+McDBo29cY1MCoC1wO3ts+c=
+google.golang.org/grpc v1.37.0/go.mod h1:NREThFqKR1f3iQ6oBuvc5LadQuXVGo9rkm5ZGrQdJfM=
 google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
 google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=
 google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQJ+fmap5saPgwCLgHXTUD7jkjRqWcaiX5VyM=
@@ -1547,6 +1561,7 @@ google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2
 google.golang.org/protobuf v1.23.1-0.20200526195155-81db48ad09cc/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
 google.golang.org/protobuf v1.24.0/go.mod h1:r/3tXBNzIEhYS9I1OUVjXDlt8tc493IdKGjtUeSXeh4=
 google.golang.org/protobuf v1.25.0/go.mod h1:9JNX74DMeImyA3h4bdi1ymwjUzf21/xIlbajtzgsN7c=
+google.golang.org/protobuf v1.25.0/go.mod h1:9JNX74DMeImyA3h4bdi1ymwjUzf21/xIlbajtzgsN7c=
 google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
 google.golang.org/protobuf v1.26.0 h1:bxAC2xTBsZGibn2RTntX0oH50xLsqy1OxA9tTL3p/lk=
 google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=

plugins/inputs/all/all.go

@@ -132,6 +132,7 @@ import (
 	_ "github.com/influxdata/telegraf/plugins/inputs/openldap"
 	_ "github.com/influxdata/telegraf/plugins/inputs/openntpd"
 	_ "github.com/influxdata/telegraf/plugins/inputs/opensmtpd"
+	_ "github.com/influxdata/telegraf/plugins/inputs/opentelemetry"
 	_ "github.com/influxdata/telegraf/plugins/inputs/openweathermap"
 	_ "github.com/influxdata/telegraf/plugins/inputs/passenger"
 	_ "github.com/influxdata/telegraf/plugins/inputs/pf"

plugins/inputs/opentelemetry/README.md

@@ -0,0 +1,78 @@
+# OpenTelemetry Input Plugin
+
+This plugin receives traces, metrics and logs from [OpenTelemetry](https://opentelemetry.io) clients and agents via gRPC.
+
+### Configuration
+
+```toml
+[[inputs.opentelemetry]]
+  ## Override the OpenTelemetry gRPC service address:port 
+  # service_address = "0.0.0.0:4317"
+  
+  ## Override the default request timeout
+  # timeout = "5s"
+  
+  ## Select a schema for metrics: "prometheus-v1" or "prometheus-v2"
+  ## For more information about the alternatives, read the Prometheus input
+  ## plugin notes.
+  # metrics_schema = "prometheus-v1"
+```
+
+#### Schema
+
+The OpenTelemetry->InfluxDB conversion [schema](https://github.com/influxdata/influxdb-observability/blob/main/docs/index.md)
+and [implementation](https://github.com/influxdata/influxdb-observability/tree/main/otel2influx)
+are hosted at https://github.com/influxdata/influxdb-observability .
+
+Spans are stored in measurement `spans`.
+Logs are stored in measurement `logs`.
+
+For metrics, two output schemata exist.
+Metrics received with `metrics_schema=prometheus-v1` are assigned measurement from the OTel field `Metric.name`.
+Metrics received with `metrics_schema=prometheus-v2` are stored in measurement `prometheus`.
+
+### Example Output
+
+#### Tracing Spans
+```
+spans end_time_unix_nano="2021-02-19 20:50:25.6893952 +0000 UTC",instrumentation_library_name="tracegen",kind="SPAN_KIND_INTERNAL",name="okey-dokey",net.peer.ip="1.2.3.4",parent_span_id="d5270e78d85f570f",peer.service="tracegen-client",service.name="tracegen",span.kind="server",span_id="4c28227be6a010e1",status_code="STATUS_CODE_OK",trace_id="7d4854815225332c9834e6dbf85b9380" 1613767825689169000
+spans end_time_unix_nano="2021-02-19 20:50:25.6893952 +0000 UTC",instrumentation_library_name="tracegen",kind="SPAN_KIND_INTERNAL",name="lets-go",net.peer.ip="1.2.3.4",peer.service="tracegen-server",service.name="tracegen",span.kind="client",span_id="d5270e78d85f570f",status_code="STATUS_CODE_OK",trace_id="7d4854815225332c9834e6dbf85b9380" 1613767825689135000
+spans end_time_unix_nano="2021-02-19 20:50:25.6895667 +0000 UTC",instrumentation_library_name="tracegen",kind="SPAN_KIND_INTERNAL",name="okey-dokey",net.peer.ip="1.2.3.4",parent_span_id="b57e98af78c3399b",peer.service="tracegen-client",service.name="tracegen",span.kind="server",span_id="a0643a156d7f9f7f",status_code="STATUS_CODE_OK",trace_id="fd6b8bb5965e726c94978c644962cdc8" 1613767825689388000
+spans end_time_unix_nano="2021-02-19 20:50:25.6895667 +0000 UTC",instrumentation_library_name="tracegen",kind="SPAN_KIND_INTERNAL",name="lets-go",net.peer.ip="1.2.3.4",peer.service="tracegen-server",service.name="tracegen",span.kind="client",span_id="b57e98af78c3399b",status_code="STATUS_CODE_OK",trace_id="fd6b8bb5965e726c94978c644962cdc8" 1613767825689303300
+spans end_time_unix_nano="2021-02-19 20:50:25.6896741 +0000 UTC",instrumentation_library_name="tracegen",kind="SPAN_KIND_INTERNAL",name="okey-dokey",net.peer.ip="1.2.3.4",parent_span_id="6a8e6a0edcc1c966",peer.service="tracegen-client",service.name="tracegen",span.kind="server",span_id="d68f7f3b41eb8075",status_code="STATUS_CODE_OK",trace_id="651dadde186b7834c52b13a28fc27bea" 1613767825689480300
+```
+
+### Metrics - `prometheus-v1`
+```
+cpu_temp,foo=bar gauge=87.332
+http_requests_total,method=post,code=200 counter=1027
+http_requests_total,method=post,code=400 counter=3
+http_request_duration_seconds 0.05=24054,0.1=33444,0.2=100392,0.5=129389,1=133988,sum=53423,count=144320
+rpc_duration_seconds 0.01=3102,0.05=3272,0.5=4773,0.9=9001,0.99=76656,sum=1.7560473e+07,count=2693
+```
+
+### Metrics - `prometheus-v2`
+```
+prometheus,foo=bar cpu_temp=87.332
+prometheus,method=post,code=200 http_requests_total=1027
+prometheus,method=post,code=400 http_requests_total=3
+prometheus,le=0.05 http_request_duration_seconds_bucket=24054
+prometheus,le=0.1  http_request_duration_seconds_bucket=33444
+prometheus,le=0.2  http_request_duration_seconds_bucket=100392
+prometheus,le=0.5  http_request_duration_seconds_bucket=129389
+prometheus,le=1    http_request_duration_seconds_bucket=133988
+prometheus         http_request_duration_seconds_count=144320,http_request_duration_seconds_sum=53423
+prometheus,quantile=0.01 rpc_duration_seconds=3102
+prometheus,quantile=0.05 rpc_duration_seconds=3272
+prometheus,quantile=0.5  rpc_duration_seconds=4773
+prometheus,quantile=0.9  rpc_duration_seconds=9001
+prometheus,quantile=0.99 rpc_duration_seconds=76656
+prometheus               rpc_duration_seconds_count=1.7560473e+07,rpc_duration_seconds_sum=2693
+```
+
+### Logs
+```
+logs fluent.tag="fluent.info",pid=18i,ppid=9i,worker=0i 1613769568895331700
+logs fluent.tag="fluent.debug",instance=1720i,queue_size=0i,stage_size=0i 1613769568895697200
+logs fluent.tag="fluent.info",worker=0i 1613769568896515100
+```

plugins/inputs/opentelemetry/grpc_services.go

@@ -0,0 +1,94 @@
+package opentelemetry
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/influxdata/influxdb-observability/common"
+	"github.com/influxdata/influxdb-observability/otel2influx"
+	otlpcollectorlogs "github.com/influxdata/influxdb-observability/otlp/collector/logs/v1"
+	otlpcollectormetrics "github.com/influxdata/influxdb-observability/otlp/collector/metrics/v1"
+	otlpcollectortrace "github.com/influxdata/influxdb-observability/otlp/collector/trace/v1"
+)
+
+type traceService struct {
+	otlpcollectortrace.UnimplementedTraceServiceServer
+
+	converter *otel2influx.OtelTracesToLineProtocol
+	writer    *writeToAccumulator
+}
+
+func newTraceService(logger common.Logger, writer *writeToAccumulator) *traceService {
+	converter := otel2influx.NewOtelTracesToLineProtocol(logger)
+	return &traceService{
+		converter: converter,
+		writer:    writer,
+	}
+}
+
+func (s *traceService) Export(ctx context.Context, req *otlpcollectortrace.ExportTraceServiceRequest) (*otlpcollectortrace.ExportTraceServiceResponse, error) {
+	err := s.converter.WriteTraces(ctx, req.ResourceSpans, s.writer)
+	if err != nil {
+		return nil, err
+	}
+	return &otlpcollectortrace.ExportTraceServiceResponse{}, nil
+}
+
+type metricsService struct {
+	otlpcollectormetrics.UnimplementedMetricsServiceServer
+
+	converter *otel2influx.OtelMetricsToLineProtocol
+	writer    *writeToAccumulator
+}
+
+var metricsSchemata = map[string]otel2influx.MetricsSchema{
+	"prometheus-v1": otel2influx.MetricsSchemaTelegrafPrometheusV1,
+	"prometheus-v2": otel2influx.MetricsSchemaTelegrafPrometheusV2,
+}
+
+func newMetricsService(logger common.Logger, writer *writeToAccumulator, schema string) (*metricsService, error) {
+	ms, found := metricsSchemata[schema]
+	if !found {
+		return nil, fmt.Errorf("schema '%s' not recognized", schema)
+	}
+
+	converter, err := otel2influx.NewOtelMetricsToLineProtocol(logger, ms)
+	if err != nil {
+		return nil, err
+	}
+	return &metricsService{
+		converter: converter,
+		writer:    writer,
+	}, nil
+}
+
+func (s *metricsService) Export(ctx context.Context, req *otlpcollectormetrics.ExportMetricsServiceRequest) (*otlpcollectormetrics.ExportMetricsServiceResponse, error) {
+	err := s.converter.WriteMetrics(ctx, req.ResourceMetrics, s.writer)
+	if err != nil {
+		return nil, err
+	}
+	return &otlpcollectormetrics.ExportMetricsServiceResponse{}, nil
+}
+
+type logsService struct {
+	otlpcollectorlogs.UnimplementedLogsServiceServer
+
+	converter *otel2influx.OtelLogsToLineProtocol
+	writer    *writeToAccumulator
+}
+
+func newLogsService(logger common.Logger, writer *writeToAccumulator) *logsService {
+	converter := otel2influx.NewOtelLogsToLineProtocol(logger)
+	return &logsService{
+		converter: converter,
+		writer:    writer,
+	}
+}
+
+func (s *logsService) Export(ctx context.Context, req *otlpcollectorlogs.ExportLogsServiceRequest) (*otlpcollectorlogs.ExportLogsServiceResponse, error) {
+	err := s.converter.WriteLogs(ctx, req.ResourceLogs, s.writer)
+	if err != nil {
+		return nil, err
+	}
+	return &otlpcollectorlogs.ExportLogsServiceResponse{}, nil
+}

plugins/inputs/opentelemetry/logger.go

@@ -0,0 +1,16 @@
+package opentelemetry
+
+import (
+	"strings"
+
+	"github.com/influxdata/telegraf"
+)
+
+type otelLogger struct {
+	telegraf.Logger
+}
+
+func (l otelLogger) Debug(msg string, kv ...interface{}) {
+	format := msg + strings.Repeat(" %s=%q", len(kv)/2)
+	l.Logger.Debugf(format, kv...)
+}

plugins/inputs/opentelemetry/opentelemetry.go

@@ -0,0 +1,101 @@
+package opentelemetry
+
+import (
+	"fmt"
+	"net"
+	"sync"
+	"time"
+
+	otlpcollectorlogs "github.com/influxdata/influxdb-observability/otlp/collector/logs/v1"
+	otlpcollectormetrics "github.com/influxdata/influxdb-observability/otlp/collector/metrics/v1"
+	otlpcollectortrace "github.com/influxdata/influxdb-observability/otlp/collector/trace/v1"
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/config"
+	"github.com/influxdata/telegraf/plugins/inputs"
+	"google.golang.org/grpc"
+)
+
+type OpenTelemetry struct {
+	ServiceAddress string          `toml:"service_address"`
+	Timeout        config.Duration `toml:"timeout"`
+
+	MetricsSchema string `toml:"metrics_schema"`
+
+	Log telegraf.Logger `toml:"-"`
+
+	grpcServer *grpc.Server
+
+	wg sync.WaitGroup
+}
+
+const sampleConfig = `
+  ## Override the OpenTelemetry gRPC service address:port 
+  # service_address = "0.0.0.0:4317"
+
+  ## Override the default request timeout
+  # timeout = "5s"
+
+  ## Select a schema for metrics: prometheus-v1 or prometheus-v2
+  ## For more information about the alternatives, read the Prometheus input
+  ## plugin notes.
+  # metrics_schema = "prometheus-v1"
+`
+
+func (o *OpenTelemetry) SampleConfig() string {
+	return sampleConfig
+}
+
+func (o *OpenTelemetry) Description() string {
+	return "Receive OpenTelemetry traces, metrics, and logs over gRPC"
+}
+
+func (o *OpenTelemetry) Gather(_ telegraf.Accumulator) error {
+	return nil
+}
+
+func (o *OpenTelemetry) Start(accumulator telegraf.Accumulator) error {
+	listener, err := net.Listen("tcp", o.ServiceAddress)
+	if err != nil {
+		return err
+	}
+
+	logger := &otelLogger{o.Log}
+	influxWriter := &writeToAccumulator{accumulator}
+	o.grpcServer = grpc.NewServer()
+
+	otlpcollectortrace.RegisterTraceServiceServer(o.grpcServer, newTraceService(logger, influxWriter))
+	ms, err := newMetricsService(logger, influxWriter, o.MetricsSchema)
+	if err != nil {
+		return err
+	}
+	otlpcollectormetrics.RegisterMetricsServiceServer(o.grpcServer, ms)
+	otlpcollectorlogs.RegisterLogsServiceServer(o.grpcServer, newLogsService(logger, influxWriter))
+
+	o.wg.Add(1)
+	go func() {
+		if err := o.grpcServer.Serve(listener); err != nil {
+			accumulator.AddError(fmt.Errorf("failed to stop OpenTelemetry gRPC service: %w", err))
+		}
+		o.wg.Done()
+	}()
+
+	return nil
+}
+
+func (o *OpenTelemetry) Stop() {
+	if o.grpcServer != nil {
+		o.grpcServer.Stop()
+	}
+
+	o.wg.Wait()
+}
+
+func init() {
+	inputs.Add("opentelemetry", func() telegraf.Input {
+		return &OpenTelemetry{
+			ServiceAddress: "0.0.0.0:4317",
+			Timeout:        config.Duration(5 * time.Second),
+			MetricsSchema:  "prometheus-v1",
+		}
+	})
+}

plugins/inputs/opentelemetry/writer.go

@@ -0,0 +1,32 @@
+package opentelemetry
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/influxdata/influxdb-observability/otel2influx"
+	"github.com/influxdata/telegraf"
+)
+
+type writeToAccumulator struct {
+	accumulator telegraf.Accumulator
+}
+
+func (w *writeToAccumulator) WritePoint(_ context.Context, measurement string, tags map[string]string, fields map[string]interface{}, ts time.Time, vType otel2influx.InfluxWriterValueType) error {
+	switch vType {
+	case otel2influx.InfluxWriterValueTypeUntyped:
+		w.accumulator.AddFields(measurement, fields, tags, ts)
+	case otel2influx.InfluxWriterValueTypeGauge:
+		w.accumulator.AddGauge(measurement, fields, tags, ts)
+	case otel2influx.InfluxWriterValueTypeSum:
+		w.accumulator.AddCounter(measurement, fields, tags, ts)
+	case otel2influx.InfluxWriterValueTypeHistogram:
+		w.accumulator.AddHistogram(measurement, fields, tags, ts)
+	case otel2influx.InfluxWriterValueTypeSummary:
+		w.accumulator.AddSummary(measurement, fields, tags, ts)
+	default:
+		return fmt.Errorf("unrecognized InfluxWriterValueType %q", vType)
+	}
+	return nil
+}