Adding Tempo for distributed tracing

Cargo.toml

@@ -157,6 +157,14 @@ num-format = "0.4.4"
 num-traits = "0.2.18"
 octocrab = "0.42.1"
 oneshot = "0.1.6"
+opentelemetry = { version = "0.30.0", features = ["trace"] }
+opentelemetry-http = "0.30.0"
+opentelemetry-otlp = { version = "0.30.0", features = [
+    "grpc-tonic",
+    "trace",
+    "tls-roots",
+] }
+opentelemetry_sdk = { version = "0.30.0", features = ["trace", "rt-tokio"] }
 papaya = "0.1.5"
 pathdiff = "0.2.1"
 port-selector = "0.1.6"
@@ -252,6 +260,7 @@ tonic-web-wasm-client = "0.8.0"
 tower = "0.4.13"
 tower-http = "0.6.6"
 tracing = { version = "0.1.40", features = ["release_max_level_debug"] }
+tracing-opentelemetry = "0.31.0"
 tracing-subscriber = { version = "0.3.18", default-features = false, features = [
     "env-filter",
 ] }

docker/Dockerfile

@@ -25,7 +25,7 @@ ARG binaries=
 ARG copy=${binaries:+_copy}
 ARG build_flag=--release
 ARG build_folder=release
-ARG build_features=scylladb,metrics,memory-profiling
+ARG build_features=scylladb,metrics,memory-profiling,tempo
 ARG rustflags="-C force-frame-pointers=yes"
 
 FROM rust:1.74-slim-bookworm AS builder

kubernetes/linera-validator/helmfile.yaml

@@ -154,3 +154,10 @@ releases:
     set:
       - name: crds.enabled
         value: "true"
+  - name: tempo
+    version: 1.23.3
+    namespace: tempo
+    chart: grafana/tempo
+    timeout: 900
+    values:
+      - {{ env "LINERA_HELMFILE_VALUES_LINERA_CORE" | default "values-local.yaml.gotmpl" }}

linera-base/Cargo.toml

@@ -18,6 +18,12 @@ workspace = true
 metrics = ["prometheus"]
 reqwest = ["dep:reqwest"]
 revm = []
+tempo = [
+    "opentelemetry",
+    "opentelemetry-otlp",
+    "opentelemetry_sdk",
+    "tracing-opentelemetry",
+]
 test = ["test-strategy", "proptest"]
 web = [
     "getrandom/js",
@@ -80,6 +86,10 @@ tracing-web = { optional = true, workspace = true }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 chrono.workspace = true
+opentelemetry = { workspace = true, optional = true }
+opentelemetry-otlp = { workspace = true, optional = true }
+opentelemetry_sdk = { workspace = true, optional = true }
+tracing-opentelemetry = { workspace = true, optional = true }
 rand = { workspace = true, features = ["getrandom", "std", "std_rng"] }
 tokio = { workspace = true, features = [
     "process",