chore(agent-data-plane): address review feedback on build metadata comments

Drop the comments narrating which values moved out of the build tooling, and restore the
build metadata description in the release docs. The comments described the change rather
than the current state, which isn't useful to a later reader.

Author: jszwedko

Makefile

@@ -11,10 +11,6 @@ export APP_GIT_HASH := $(or $(CI_COMMIT_SHA),$(shell git rev-parse --short HEAD
 export APP_BUILD_TIME := $(or $(CI_PIPELINE_CREATED_AT),0000-00-00T00:00:00-00:00)
 
 # ADP-specific settings used during builds.
-#
-# ADP's name and version aren't here: the binary declares them itself (see `declare_app_details!` in
-# bin/agent-data-plane/src/main.rs) and Cargo supplies the version, so builds no longer pass them in. ADP_APP_VERSION
-# survives only because release artifacts are named after it.
 export ADP_APP_GIT_HASH := $(APP_GIT_HASH)
 export ADP_APP_VERSION_AUTO := $(shell cat bin/agent-data-plane/Cargo.toml | grep -E "^version = \"" | head -n 1 | cut -d '"' -f 2)
 export ADP_APP_VERSION := $(or $(ADP_APP_VERSION),$(ADP_APP_VERSION_AUTO))

ci/tooling/build-adp-aix.sh

@@ -30,7 +30,6 @@ export CARGO_TARGET_DIR
 
 APP_GIT_HASH_AUTO="$(git -C "${repo_root}" rev-parse --short HEAD 2>/dev/null || echo not-in-git)"
 
-# Only build metadata is passed in; ADP declares its own name and Cargo supplies its version.
 export APP_GIT_HASH="${APP_GIT_HASH:-${ADP_APP_GIT_HASH:-${APP_GIT_HASH_AUTO}}}"
 # Unlike the Makefile, this script defaults APP_DEV_BUILD to "false", so it can't fall back to a placeholder
 # timestamp: saluki-metadata rejects placeholder metadata on release builds. Stamp the current time instead.

ci/tooling/windows-build-adp.ps1

@@ -46,8 +46,7 @@ Install-CachedZipTool `
 
 # saluki-metadata reads these at build time. Must match what the Makefile passes through
 # (ADP_APP_GIT_HASH / ADP_APP_BUILD_TIME) so the Windows binary reports the same build
-# metadata as the linux/darwin binaries do. The application's name and version aren't here:
-# ADP declares those itself and Cargo supplies the version.
+# metadata as the linux/darwin binaries do.
 # Windows PowerShell 5.1 (the default `powershell.exe` in the LTSC2022 build image) doesn't
 # have Get-Date's -AsUTC switch (added in PS 7.1). ToUniversalTime() works on both.
 $env:APP_BUILD_TIME = (Get-Date).ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ssZ")

ci/tooling/windows-integration-tests.ps1

@@ -57,8 +57,7 @@ if (-not (Get-Command docker -ErrorAction SilentlyContinue)) {
 Invoke-Native docker version
 
 Write-Host "[*] Building Panoramic and Agent Data Plane for Windows..."
-# saluki-metadata reads these at build time. ADP declares its own name and version, so only
-# build metadata is passed in here.
+# saluki-metadata reads these at build time.
 # Windows PowerShell 5.1 doesn't have Get-Date's -AsUTC switch (added in PS 7.1).
 $env:APP_BUILD_TIME = (Get-Date).ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ssZ")
 if (-not $env:APP_GIT_HASH) {

docs/agent-data-plane/releasing.md

@@ -81,12 +81,8 @@ during the build process and is used to drive a number of behaviors:
 - outputting the version of ADP, when it was built, the build architecture, etc, as a log at startup
 - special constant identifiers that are used to populate things like HTTP request headers (user agent, etc)
 
-ADP's identity—its full name, short name, identifier, and version—isn't passed in by the build. The binary declares it
-in `bin/agent-data-plane/src/main.rs` using `saluki_metadata::declare_app_details!`, and Cargo supplies the version from
-`bin/agent-data-plane/Cargo.toml`. Changing any of those means editing that declaration, not the build tooling.
-
-What remains describes the build rather than the application, and is calculated with a Make
-target—`emit-adp-build-metadata`—which populates it during local builds or regular CI builds:
+This build metadata is calculated with a Make target—`emit-adp-build-metadata`—which populates it during local builds or
+regular CI builds. The relevant build arguments are all prefixed with `APP_` and are as follows:
 
 - `APP_GIT_HASH`: the Git commit the build was performed from (set to the GitLab CI commit SHA)
 - `APP_BUILD_TIME`: the time the build was performed (set to the creation time of the GitLab CI pipeline)