src/context/propagation/encoder.rs

// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements.  See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to You 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.
//

use crate::context::trace_context::TracingContext;
use base64::encode;

/// Encode TracingContext to carry current trace info to the destination of RPC call.
/// In general, the output of this function will be packed in `sw8` header in HTTP call.
pub fn encode_propagation(context: &TracingContext, endpoint: &str, address: &str) -> String {
    let mut res = String::new();

    res += "1-";
    res += format!("{}-", encode(context.trace_id.to_string())).as_str();
    res += format!("{}-", encode(context.trace_segment_id.to_string())).as_str();
    res += format!("{}-", context.peek_active_span_id().unwrap_or(0)).as_str();
    res += format!("{}-", encode(context.service.as_str())).as_str();
    res += format!("{}-", encode(context.service_instance.as_str())).as_str();
    res += format!("{}-", encode(endpoint)).as_str();
    res += &encode(address);
    res
}