From 3b971e3ab83356a60e05b62c7aca263eb9760634 Mon Sep 17 00:00:00 2001
From: David Schmitt <david.schmitt@overmind.tech>
Date: Tue, 7 Jan 2025 16:10:09 +0100
Subject: [PATCH] Replace commit.txt with ldflags value

---
 .github/workflows/test-build.yml |  1 -
 .gitignore                       |  1 -
 build/package/Dockerfile         |  2 +-
 tracing/tracing.go               | 12 +++++++++---
 4 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/.github/workflows/test-build.yml b/.github/workflows/test-build.yml
index 10ecbac5..b4be4483 100644
--- a/.github/workflows/test-build.yml
+++ b/.github/workflows/test-build.yml
@@ -35,7 +35,6 @@ jobs:
       - name: Go Generate
         run: |
           go generate ./...
-          cat tracing/commit.txt
 
       - name: Validate Docs Data
         run: |
diff --git a/.gitignore b/.gitignore
index 730ddcf3..eb0a03cb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,6 +7,5 @@ vendor
 Gopkg.lock
 build/compiled
 .idea
-commit.txt
 .envrc
 .golangci.yml
diff --git a/build/package/Dockerfile b/build/package/Dockerfile
index 29bb750e..93c21d88 100644
--- a/build/package/Dockerfile
+++ b/build/package/Dockerfile
@@ -23,7 +23,7 @@ COPY . .
 RUN --mount=type=cache,target=/go/pkg \
     --mount=type=cache,target=/root/.cache/go-build \
     go generate ./... \
-    && GOOS=${TARGETOS} GOARCH=${TARGETARCH} go build -ldflags="-s -w" -trimpath -o source main.go
+    && GOOS=${TARGETOS} GOARCH=${TARGETARCH} go build -ldflags="-s -w -X github.com/overmindtech/aws-source/tracing.ServiceVersion=$(git describe --tags --exact-match 2>/dev/null || git rev-parse --short HEAD)" -trimpath -o source main.go
 
 FROM alpine:3.21
 WORKDIR /
diff --git a/tracing/tracing.go b/tracing/tracing.go
index 6ff42a00..fa371b71 100644
--- a/tracing/tracing.go
+++ b/tracing/tracing.go
@@ -22,9 +22,15 @@ import (
 	semconv "go.opentelemetry.io/otel/semconv/v1.26.0"
 )
 
-//go:generate sh -c "echo -n $(git describe --tags --exact-match 2>/dev/null || git rev-parse --short HEAD) > commit.txt"
-//go:embed commit.txt
-var ServiceVersion string
+// ServiceVersion is the version of the service. This will be overridden by the
+// build system, using:
+// go build -ldflags "-X github.com/overmindtech/api-server/tracing.ServiceVersion=$(git describe --tags --exact-match 2>/dev/null || git rev-parse --short HEAD)" -o your-app
+//
+// This allows our change detection workflow to work correctly. If we were
+// embedding the version here each time we would always produce a slightly
+// different compiled binary, and therefore it would look like there was a
+// change each time
+var ServiceVersion = "dev"
 
 func tracingResource() *resource.Resource {
 	// Identify your application using resource detection