Use capnp map for tracing metadata

conmon-rs/common/proto/conmon.capnp

@@ -5,7 +5,8 @@ interface Conmon {
     # Version
     struct VersionRequest {
         verbose @0 :Bool;
-        metadata @1 :Data;
+        metadataOld @1 :Data; # deprecated
+        metadata @2 :Metadata; # Standard metadata to carry.
     }
 
     struct VersionResponse {
@@ -18,7 +19,7 @@ interface Conmon {
         rustVersion @6 :Text;
         cargoVersion @7 :Text;
         cargoTree @8 :Text;
-        metadata @9 :Data;
+        metadata @9 :Data; # deprecated (never used, remove in next major release)
     }
 
     version @0 (request: VersionRequest) -> (response: VersionResponse);
@@ -36,7 +37,8 @@ interface Conmon {
         cleanupCmd @7 :List(Text);
         globalArgs @8 :List(Text);
         commandArgs @9 :List(Text);
-        metadata @10 :Data;
+        metadataOld @10 :Data; # deprecated
+        metadata @11 :Metadata; # Standard metadata to carry.
     }
 
     struct LogDriver {
@@ -68,7 +70,8 @@ interface Conmon {
         timeoutSec @1 :UInt64;
         command @2 :List(Text);
         terminal @3 :Bool;
-        metadata @4 :Data;
+        metadataOld @4 :Data; # deprecated
+        metadata @5 :Metadata; # Standard metadata to carry.
     }
 
     struct ExecSyncContainerResponse {
@@ -87,7 +90,8 @@ interface Conmon {
         socketPath @1 :Text;
         execSessionId @2 :Text;
         stopAfterStdinEof @3 :Bool;
-        metadata @4 :Data;
+        metadataOld @4 :Data; # deprecated
+        metadata @5 :Metadata; # Standard metadata to carry.
     }
 
     struct AttachResponse {
@@ -99,7 +103,8 @@ interface Conmon {
     # ReopenLog
     struct ReopenLogRequest {
         id @0 :Text;
-        metadata @1 :Data;
+        metadataOld @1 :Data; # deprecated
+        metadata @2 :Metadata; # Standard metadata to carry.
     }
 
     struct ReopenLogResponse {
@@ -113,7 +118,9 @@ interface Conmon {
         id @0 :Text; # container identifier
         width @1 :UInt16; # columns in characters
         height @2 :UInt16; # rows in characters
-        metadata @3 :Data;
+        metadataOld @3 :Data; # deprecated
+        metadata @4 :Metadata; # Standard metadata to carry.
+
     }
 
     struct SetWindowSizeResponse {
@@ -124,12 +131,13 @@ interface Conmon {
     ###############################################
     # CreateNamespaces
     struct CreateNamespacesRequest {
-        metadata @0 :Data; # Standard metadata to carry.
+        metadataOld @0 :Data; # deprecated
         namespaces @1 :List(Namespace); # The list of namespaces to unshare.
         uidMappings @2 :List(Text); # User ID mappings when unsharing the user namespace.
         gidMappings @3 :List(Text); # Group ID mappings when unsharing the user namespace.
         basePath @4 :Text; # The root path for storing the namespaces.
         podId @5 :Text; # The pod identifier.
+        metadata @6 :Metadata; # Standard metadata to carry.
     }
 
     enum Namespace {
@@ -151,4 +159,14 @@ interface Conmon {
     }
 
     createNamespaces @6 (request: CreateNamespacesRequest) -> (response: CreateNamespacesResponse);
+
+    ###############################################
+    # Helper types
+
+    using Metadata = TextTextMap;
+    using TextTextMap = List(TextTextMapEntry);
+    struct TextTextMapEntry {
+        key @0 :Text;
+        value @1 :Text;
+    }
 }

conmon-rs/server/Cargo.toml

@@ -30,7 +30,6 @@ prctl = "1.0.0"
 regex = "1.9.1"
 sendfd = { version = "0.4.3", features = ["tokio"] }
 serde = { version = "1.0.171", features = ["derive"] }
-serde_json = "1.0.102"
 shadow-rs = "=0.23.0"
 signal-hook = "0.3.16"
 strum = { version = "0.25.0", features = ["derive"] }

conmon-rs/server/src/capnp_util.rs

@@ -0,0 +1,81 @@
+pub(crate) use map_entry::into_map;
+
+#[allow(unused)]
+pub(crate) use map_entry::set_map;
+
+/// Helper functions to convert between capnp maps (List's of MapEntries) and rust maps
+mod map_entry {
+    use capnp::{
+        struct_list::{Builder, Reader},
+        traits::OwnedStruct,
+    };
+    use conmon_common::conmon_capnp::conmon;
+
+    /// Convert from a MapEntry capnp struct to a (key, value) tuple.
+    pub(crate) trait IntoKeyValue<'a, K, V>: OwnedStruct {
+        fn into_key_value(entry: Self::Reader<'a>) -> capnp::Result<(K, V)>;
+    }
+
+    /// Set the key and value properties of a MapEntry capnp struct.
+    pub(crate) trait SetKeyValue<K, V>: OwnedStruct {
+        fn set_key_value(entry: Self::Builder<'_>, key: K, value: V);
+    }
+
+    impl<'a, K, V> IntoKeyValue<'a, K, V> for conmon::text_text_map_entry::Owned
+    where
+        K: From<&'a str>,
+        V: From<&'a str>,
+    {
+        fn into_key_value(entry: Self::Reader<'a>) -> capnp::Result<(K, V)> {
+            Ok((entry.get_key()?.into(), entry.get_value()?.into()))
+        }
+    }
+
+    impl<K, V> SetKeyValue<K, V> for conmon::text_text_map_entry::Owned
+    where
+        K: AsRef<str>,
+        V: AsRef<str>,
+    {
+        fn set_key_value(mut entry: Self::Builder<'_>, key: K, value: V) {
+            entry.set_key(key.as_ref());
+            entry.set_value(value.as_ref());
+        }
+    }
+
+    /// Convert a capnp map reader (`struct_list::Reader`) into a rust map (`impl FromIterator<(K, V)>`).
+    pub(crate) fn into_map<'a, K, V, E, T>(reader: Reader<'a, E>) -> capnp::Result<T>
+    where
+        E: IntoKeyValue<'a, K, V>,
+        T: FromIterator<(K, V)>,
+    {
+        reader.into_iter().map(E::into_key_value).collect()
+    }
+
+    /// Set a capnp map property from a rust map (`impl IntoIterator<Item=(K, V)>`).
+    ///
+    /// The `init` function is used to allocate a `struct_list::Builder`.
+    ///
+    /// ## Example
+    /// Set the `exampleMap` property in the response capnp builder to the rust map `data`
+    /// ```ignore
+    /// set_from_map(data, |size| response.init_example_map(size));
+    /// ```
+    pub(crate) fn set_map<'a, K, V, E, T>(data: T, init: impl FnOnce(u32) -> Builder<'a, E>)
+    where
+        T: IntoIterator<Item = (K, V)>,
+        T::IntoIter: ExactSizeIterator,
+        E: SetKeyValue<K, V>,
+    {
+        let data = data.into_iter();
+        let size = if let Ok(size) = data.len().try_into() {
+            size
+        } else {
+            panic!("map with more then u32::MAX entries")
+        };
+        let mut list = init(size);
+        for (i, (key, value)) in data.enumerate() {
+            let entry = list.reborrow().get(i as u32);
+            E::set_key_value(entry, key, value);
+        }
+    }
+}

conmon-rs/server/src/lib.rs

@@ -5,6 +5,7 @@ pub use server::Server;
 pub use version::Version;
 
 mod attach;
+mod capnp_util;
 mod child;
 mod child_reaper;
 mod config;

conmon-rs/server/src/telemetry.rs

@@ -1,6 +1,9 @@
 /// Open Telemetry related source code.
+use crate::capnp_util;
 use anyhow::{Context, Result};
+use capnp::struct_list::Reader;
 use clap::crate_name;
+use conmon_common::conmon_capnp::conmon;
 use nix::unistd::gethostname;
 use opentelemetry::{
     global,
@@ -63,13 +66,13 @@ impl Telemetry {
     }
 
     /// Set a new parent context from the provided slice data.
-    pub fn set_parent_context(slice: &'_ [u8]) -> Result<()> {
-        if slice.is_empty() {
+    pub fn set_parent_context(reader: Reader<conmon::text_text_map_entry::Owned>) -> Result<()> {
+        if reader.is_empty() {
             // Make it a noop if no data is provided.
             return Ok(());
         }
 
-        let metadata = Metadata(serde_json::from_slice(slice).context("parse slice as JSON")?);
+        let metadata = Metadata(capnp_util::into_map(reader)?);
         let ctx = global::get_text_map_propagator(|prop| prop.extract(&metadata));
         Span::current().set_parent(ctx);