Open source


otelcol.receiver.opencensus accepts telemetry data via gRPC or HTTP using the OpenCensus format and forwards it to other otelcol.* components.

NOTE: otelcol.receiver.opencensus is a wrapper over the upstream OpenTelemetry Collector opencensus receiver from the otelcol-contrib distribution. Bug reports or feature requests will be redirected to the upstream repository, if necessary.

Multiple otelcol.receiver.opencensus components can be specified by giving them different labels.


otelcol.receiver.opencensus "LABEL" {
  output {
    metrics = [...]
    logs    = [...]
    traces  = [...]


otelcol.receiver.opencensus supports the following arguments:

cors_allowed_originslist(string)A list of allowed Cross-Origin Resource Sharing (CORS)
endpointstringhost:port to listen for traffic on.""no
transportstringTransport to use for the gRPC server."tcp"no
max_recv_msg_sizestringMaximum size of messages the server will accept."4MiB"no
max_concurrent_streamsnumberLimit the number of concurrent streaming RPC
read_buffer_sizestringSize of the read buffer the gRPC server will use for reading from clients."512KiB"no
write_buffer_sizestringSize of the write buffer the gRPC server will use for writing to
include_metadatabooleanPropagate incoming connection metadata to downstream

cors_allowed_origins are the allowed CORS origins for HTTP/JSON requests. An empty list means that CORS is not enabled at all. A wildcard (*) can be used to match any origin or one or more characters of an origin.

The “endpoint” parameter is the same for both gRPC and HTTP/JSON, as the protocol is recognized and processed accordingly.

To write traces with HTTP/JSON, POST to [address]/v1/trace. The JSON message format parallels the gRPC protobuf format. For details, refer to its OpenApi specification.

Note that max_recv_msg_size, read_buffer_size and write_buffer_size are formatted in a way so that the units are included in the string, such as “512KiB” or “1024KB”.


The following blocks are supported inside the definition of otelcol.receiver.opencensus:

tlstlsConfigures TLS for the gRPC
keepalivekeepaliveConfigures keepalive settings for the configured
keepalive > server_parametersserver_parametersServer parameters used to configure keepalive
keepalive > enforcement_policyenforcement_policyEnforcement policy for keepalive
debug_metricsdebug_metricsConfigures the metrics that this component generates to monitor its
outputoutputConfigures where to send received telemetry data.yes

The > symbol indicates deeper levels of nesting. For example, grpc > tls refers to a tls block defined inside a grpc block.

tls block

The tls block configures TLS settings used for a server. If the tls block isn’t provided, TLS won’t be used for connections to the server.

The following arguments are supported:

ca_filestringPath to the CA
ca_pemstringCA PEM-encoded text to validate the server
cert_filestringPath to the TLS
cert_pemstringCertificate PEM-encoded text for client
include_system_ca_certs_poolbooleanWhether to load the system certificate authorities pool alongside the certificate authority.falseno
key_filestringPath to the TLS certificate
key_pemsecretKey PEM-encoded text for client
max_versionstringMaximum acceptable TLS version for connections."TLS 1.3"no
min_versionstringMinimum acceptable TLS version for connections."TLS 1.2"no
cipher_suiteslist(string)A list of TLS cipher suites that the TLS transport can use.[]no
reload_intervaldurationThe duration after which the certificate is reloaded."0s"no
client_ca_filestringPath to the TLS cert to use by the server to verify a client

If reload_interval is set to "0s", the certificate never reloaded.

The following pairs of arguments are mutually exclusive and can’t both be set simultaneously:

  • ca_pem and ca_file
  • cert_pem and cert_file
  • key_pem and key_file

If cipher_suites is left blank, a safe default list is used. Refer to the Go Cipher Suites documentation for a list of supported cipher suites.

client_ca_file sets the ClientCA and ClientAuth to RequireAndVerifyClientCert in the TLSConfig. Refer to the Go TLS documentation for more information.

keepalive block

The keepalive block configures keepalive settings for connections to a gRPC server.

keepalive doesn’t support any arguments and is configured fully through inner blocks.

server_parameters block

The server_parameters block controls keepalive and maximum age settings for gRPC servers.

The following arguments are supported:

max_connection_idledurationMaximum age for idle connections."infinity"no
max_connection_agedurationMaximum age for non-idle connections."infinity"no
max_connection_age_gracedurationTime to wait before forcibly closing connections."infinity"no
timedurationHow often to ping inactive clients to check for liveness."2h"no
timeoutdurationTime to wait before closing inactive clients that do not respond to liveness checks."20s"no

enforcement_policy block

The enforcement_policy block configures the keepalive enforcement policy for gRPC servers. The server will close connections from clients that violate the configured policy.

The following arguments are supported:

min_timedurationMinimum time clients should wait before sending a keepalive ping."5m"no
permit_without_streambooleanAllow clients to send keepalive pings when there are no active streams.falseno

debug_metrics block

The debug_metrics block configures the metrics that this component generates to monitor its state.

The following arguments are supported:

disable_high_cardinality_metricsbooleanWhether to disable certain high cardinality metrics.trueno
levelstringControls the level of detail for metrics emitted by the wrapped collector."detailed"no

disable_high_cardinality_metrics is the Grafana Alloy equivalent to the telemetry.disableHighCardinalityMetrics feature gate in the OpenTelemetry Collector. It removes attributes that could cause high cardinality metrics. For example, attributes with IP addresses and port numbers in metrics about HTTP and gRPC connections are removed.


If configured, disable_high_cardinality_metrics only applies to otelcol.exporter.* and otelcol.receiver.* components.

level is the Alloy equivalent to the telemetry.metrics.level feature gate in the OpenTelemetry Collector. Possible values are "none", "basic", "normal" and "detailed".

output block

The output block configures a set of components to forward resulting telemetry data to.

The following arguments are supported:

logslist(otelcol.Consumer)List of consumers to send logs to.[]no
metricslist(otelcol.Consumer)List of consumers to send metrics to.[]no
traceslist(otelcol.Consumer)List of consumers to send traces to.[]no

You must specify the output block, but all its arguments are optional. By default, telemetry data is dropped. Configure the metrics, logs, and traces arguments accordingly to send telemetry data to other components.

Exported fields

otelcol.receiver.opencensus does not export any fields.

Component health

otelcol.receiver.opencensus is only reported as unhealthy if given an invalid configuration.

Debug information

otelcol.receiver.opencensus does not expose any component-specific debug information.


This example forwards received telemetry data through a batch processor before finally sending it to an OTLP-capable endpoint:

otelcol.receiver.opencensus "default" {
    cors_allowed_origins = ["https://*", ""]

    endpoint  = ""
    transport = "tcp"

    max_recv_msg_size      = "32KB"
    max_concurrent_streams = "16"
    read_buffer_size       = "1024KB"
    write_buffer_size      = "1024KB"
    include_metadata       = true

    tls {
        cert_file = "test.crt"
        key_file  = "test.key"

    keepalive {
        server_parameters {
            max_connection_idle      = "11s"
            max_connection_age       = "12s"
            max_connection_age_grace = "13s"
            time                     = "30s"
            timeout                  = "5s"

        enforcement_policy {
            min_time              = "10s"
            permit_without_stream = true

    output {
        metrics = [otelcol.processor.batch.default.input]
        logs    = [otelcol.processor.batch.default.input]
        traces  = [otelcol.processor.batch.default.input]

otelcol.processor.batch "default" {
    output {
        metrics = [otelcol.exporter.otlp.default.input]
        logs    = [otelcol.exporter.otlp.default.input]
        traces  = [otelcol.exporter.otlp.default.input]

otelcol.exporter.otlp "default" {
    client {
        endpoint = env("OTLP_ENDPOINT")

Compatible components

otelcol.receiver.opencensus can accept arguments from the following components:


Connecting some components may not be sensible or components may require further configuration to make the connection work correctly. Refer to the linked documentation for more details.