maintaining-dependencies.md

Maintaining dependencies

In general, several places in the code base need to be adjusted when upgrading a dependency to a new version.

This documentation contains notes about which place to fix, to make maintenance easier and less error prone.

This doc is only useful when up to date, so make sure to add details about missing parts if any.

Also, another good place to start when upgrading something to N+1 is to find the commit that upgraded to version N (use git blame), and inspect the commit for the last upgrade.

opentelemetry-proto

Comments (opentelemetry-proto)

Unlike other opentelemetry SIGs, opentelemetry-cpp generates code from opentelemetry-proto as part of the opentelemetry-cpp build.

Only the source code of opentelemetry-proto is required, which is why this repository is used as a git submodule under third_party.

Code is generated by the protobuf compiler during the build, so that generated code is never checked in.

This allows more flexibility, should the compiler (protobuf) be upgraded even when the source code (opentelemetry-proto) is unchanged.

Origin (opentelemetry-proto)

The repository for opentelemetry-proto is:

• repository

Check release notes at:

• release-notes

Upgrade (opentelemetry-proto)

When upgrading opentelemetry-proto to a newer release, a few places in the code need adjustment.

In this example, we upgrade from 1.3.1 to 1.3.2

directory third_party/opentelemetry-proto

This is a git submodule, it needs to point to the new tag.

cd third_party/opentelemetry-proto
git log -1

The current submodule show something like:

commit b3060d2104df364136d75a35779e6bd48bac449a (HEAD, tag: v1.3.1)
Author: Damien Mathieu <[email protected]>
Date:   Thu Apr 25 17:55:35 2024 +0200

    generate profiles proto for CI (#552)

Pull new tags:

git pull --tag origin

Upgrade to a new tag:

git pull origin v1.3.2

Check the new state:

git log -1

commit 40b3c1b746767cbc13c2e39da3eaf1a23e54ffdd (HEAD, tag: v1.3.2)
Author: jack-berg <[email protected]>
Date:   Fri Jun 28 08:19:11 2024 -0500

    Prepare changelog for 1.3.2 release (#563)

    Co-authored-by: Armin Ruech <[email protected]>

Go back to the root of opentelemetry-cpp

cd ../..
git status

On branch upgrade_proto_1.3.2
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
        modified:   third_party/opentelemetry-proto (new commits)

Add the upgraded submodule:

git add third_party/opentelemetry-proto

file third_party_release

Update the line pointing to the opentelemetry-proto tag.

opentelemetry-proto=v1.3.2

Typical change:

[malff@malff-desktop opentelemetry-cpp]$ git diff third_party_release
diff --git a/third_party_release b/third_party_release
index 0bbf67f3..7362473f 100644
--- a/third_party_release
+++ b/third_party_release
@@ -19,7 +19,7 @@ benchmark=v1.8.3
 googletest=1.14.0
 ms-gsl=v3.1.0-67-g6f45293
 nlohmann-json=v3.11.3
-opentelemetry-proto=v1.3.1
+opentelemetry-proto=v1.3.2
 opentracing-cpp=v1.6.0
 prometheus-cpp=v1.2.4
 vcpkg=2024.02.14

file bazel/repository.bzl

Locate the entry for opentelemetry-proto:

    # OTLP Protocol definition
    maybe(
        http_archive,
        name = "com_github_opentelemetry_proto",
        build_file = "@io_opentelemetry_cpp//bazel:opentelemetry_proto.BUILD",
        sha256 = "bed250ceec8e4a83aa5604d7d5595a61945059dc662edd058a9da082283f7a00",
        strip_prefix = "opentelemetry-proto-1.3.1",
        urls = [
            "https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.1.tar.gz",
        ],
    )

Update the URL to the new tag:

        urls = [
            "https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.2.tar.gz",
        ],

Update strip_prefix to the new tag:

        strip_prefix = "opentelemetry-proto-1.3.2",

Download the new URL:

wget https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.2.tar.gz

Run a checksum on the new file:

sha256sum v1.3.2.tar.gz

c069c0d96137cf005d34411fa67dd3b6f1f8c64af1e7fb2fe0089a41c425acd7  v1.3.2.tar.gz

Update the checksum in file bazel/repository.bzl:

        sha256 = "c069c0d96137cf005d34411fa67dd3b6f1f8c64af1e7fb2fe0089a41c425acd7",

Typical change:

[malff@malff-desktop opentelemetry-cpp]$ git diff bazel/repository.bzl
diff --git a/bazel/repository.bzl b/bazel/repository.bzl
index bac1e45b..508b95a3 100644
--- a/bazel/repository.bzl
+++ b/bazel/repository.bzl
@@ -88,10 +88,10 @@ def opentelemetry_cpp_deps():
         http_archive,
         name = "com_github_opentelemetry_proto",
         build_file = "@io_opentelemetry_cpp//bazel:opentelemetry_proto.BUILD",
-        sha256 = "bed250ceec8e4a83aa5604d7d5595a61945059dc662edd058a9da082283f7a00",
-        strip_prefix = "opentelemetry-proto-1.3.1",
+        sha256 = "c069c0d96137cf005d34411fa67dd3b6f1f8c64af1e7fb2fe0089a41c425acd7",
+        strip_prefix = "opentelemetry-proto-1.3.2",
         urls = [
-            "https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.1.tar.gz",
+            "https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.2.tar.gz",
         ],
     )

file cmake/opentelemetry-proto.cmake

Update the tag in the CMake logic:

        set(opentelemetry-proto "v1.3.2")

Typical change:

[malff@malff-desktop opentelemetry-cpp]$ git diff cmake/opentelemetry-proto.cmake
diff --git a/cmake/opentelemetry-proto.cmake b/cmake/opentelemetry-proto.cmake
index 19516c3b..dd6213c1 100644
--- a/cmake/opentelemetry-proto.cmake
+++ b/cmake/opentelemetry-proto.cmake
@@ -49,7 +49,7 @@ else()
          "opentelemetry-proto=[ \\t]*([A-Za-z0-9_\\.\\-]+)")
         set(opentelemetry-proto "${CMAKE_MATCH_1}")
       else()
-        set(opentelemetry-proto "v1.3.1")
+        set(opentelemetry-proto "v1.3.2")
       endif()
       unset(OTELCPP_THIRD_PARTY_RELEASE_CONTENT)
     endif()

If opentelemetry-proto contains new files, the makefile needs to be adjusted to build the new code.

Depending on the actual changes in the opentelemetry-proto files, the C++ code in opentelemetry-cpp may need adjustments.

Typically, when opentelemetry-proto:

• defines a new message (for example, for profiling)
• adds new optional fields to an existing message (for example, trace flags)

the existing C++ code should work as is with the new opentelemetry-proto format.

In this case, it is better to:

• upgrade the opentelemetry-proto version independently with one PR.
• upgrade the C++ code later (to use the new message, of provide new fields) in a different PR.

When the C++ code requires a newer minimum version of opentelemetry-proto, make sure to document this, including in the release notes.

file MODULE.bazel

Make sure the new tag is available in bazel central:

• bazel-central

If missing, file a PR to add it, or contact the maintainer:

• repository

Update the opentelemetry-proto version to the new tag:

bazel_dep(name = "opentelemetry-proto", version = "1.3.2", repo_name = "com_github_opentelemetry_proto")

File MODULE.bazel is used in the github CI for repository opentelemetry-cpp, so using a tag that does not exist (yet) in bazel central will break the CI build.

See the known issues section.

Typical change:

[malff@malff-desktop opentelemetry-cpp]$ git diff MODULE.bazel
diff --git a/MODULE.bazel b/MODULE.bazel
index 7b84c2b7..3161ffb1 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -13,7 +13,7 @@ bazel_dep(name = "bazel_skylib", version = "1.5.0")
 bazel_dep(name = "curl", version = "8.4.0")
 bazel_dep(name = "grpc", version = "1.62.1", repo_name = "com_github_grpc_grpc")
 bazel_dep(name = "nlohmann_json", version = "3.11.3", repo_name = "github_nlohmann_json")
-bazel_dep(name = "opentelemetry-proto", version = "1.3.1", repo_name = "com_github_opentelemetry_proto")
+bazel_dep(name = "opentelemetry-proto", version = "1.3.2", repo_name = "com_github_opentelemetry_proto")
 bazel_dep(name = "opentracing-cpp", version = "1.6.0", repo_name = "com_github_opentracing")
 bazel_dep(name = "platforms", version = "0.0.8")
 bazel_dep(name = "prometheus-cpp", version = "1.2.4", repo_name = "com_github_jupp0r_prometheus_cpp")

Known issues (opentelemetry-proto)

For bazel, two different methods to build exists.

First, the code can build using file bazel/repository.bzl. This option does not depend on bazel central.

Secondly, there is also a build using modules, with file MODULE.bazel. This option does depend on bazel central, and CI depends on it.

semantic-conventions and build-tools

Comments (semantic-conventions)

Some code in opentelemetry-cpp is generated automatically, namely files:

• api/include/opentelemetry/trace/semantic_conventions.h
• sdk/include/opentelemetry/sdk/resource/semantic_conventions.h

The semantic conventions C++ declarations are generated using:

• data represented in yaml ("semantic-conventions")
• a code generator ("build-tools")

This generation is not done as part of the build, it is done once by maintainers, and the generated code is added (checked in) in the opentelemetry-cpp repository.

Origin (semantic-conventions)

The repository for semantic-conventions is:

• repository

Check release notes at:

• release-notes

The repository for build-tools is:

• repository

Check release notes at:

• release-notes

Semantic conventions and build-tools works together, make sure to use the proper version of build-tools that is required to use a given version of semantic-conventions.

Upgrade (semantic-conventions)

When upgrading semantic-conventions to a newer release, a few places in the code need adjustment.

In this example, we upgrade from semantic-conventions 1.26.0 to 1.27.0

In this case, semantic-conventions 1.27.0 also require a new version of build-tools, because the yaml format for the data changed.

In this example, we upgrade from build-tools 0.24.0 to 0.25.0

file buildscripts/semantic-convention/generate.sh

Update the line pointing to the semantic-conventions tag.

SEMCONV_VERSION=1.27.0

Update the line pointing to the build-tools tag.

GENERATOR_VERSION=0.25.0

Typical change:

[malff@malff-desktop opentelemetry-cpp]$ git diff buildscripts/semantic-convention/generate.sh
diff --git a/buildscripts/semantic-convention/generate.sh b/buildscripts/semantic-convention/generate.sh
index 2bcd07e2..8ad3292e 100755
--- a/buildscripts/semantic-convention/generate.sh
+++ b/buildscripts/semantic-convention/generate.sh
@@ -19,10 +19,10 @@ ROOT_DIR="${SCRIPT_DIR}/../../"
 #   https://github.com/open-telemetry/opentelemetry-specification
 # Repository from 1.21.0:
 #   https://github.com/open-telemetry/semantic-conventions
-SEMCONV_VERSION=1.26.0
+SEMCONV_VERSION=1.27.0

 # repository: https://github.com/open-telemetry/build-tools
-GENERATOR_VERSION=0.24.0
+GENERATOR_VERSION=0.25.0

 SPEC_VERSION=v$SEMCONV_VERSION
 SCHEMA_URL=https://opentelemetry.io/schemas/$SEMCONV_VERSION

This change alone does nothing, the next step is to execute the generate.sh script.

If generation is successful, the generated code contains the new schema URL:

[malff@malff-desktop opentelemetry-cpp]$ find . -name semantic_conventions.h
./api/include/opentelemetry/trace/semantic_conventions.h
./sdk/include/opentelemetry/sdk/resource/semantic_conventions.h
[malff@malff-desktop opentelemetry-cpp]$ grep kSchemaUrl ./api/include/opentelemetry/trace/semantic_conventions.h
static constexpr const char *kSchemaUrl = "https://opentelemetry.io/schemas/1.27.0";
[malff@malff-desktop opentelemetry-cpp]$ grep kSchemaUrl ./sdk/include/opentelemetry/sdk/resource/semantic_conventions.h
static constexpr const char *kSchemaUrl = "https://opentelemetry.io/schemas/1.27.0";

Apply clang-format on the generated code, and check-in changes.

Known issues (semantic-conventions)

Depending on tooling changes, the generate.sh script may need adjustments.

Depending on changes in code generation, the template used to generate code may need adjustments.

This template is implemented in file buildscripts/semantic-convention/templates/SemanticAttributes.h.j2.

Last, in some special case like name collisions for a given symbol, the template itself may need to be adjusted for special logic.

See for example how messaging.client_id is treated.