Fix instructions and dependencies (#434)

Signed-off-by: Chance Zibolski <chance.zibolski@gmail.com>

CHANGELOG.md

@@ -115,3 +115,5 @@ significant modifications will be credited to OpenTelemetry Authors.
 ([#416](https://github.com/open-telemetry/opentelemetry-demo/pull/416))
 * Replaced the Jaeger exporter to the OTLP exporter in the OTel Collector
 ([#435](https://github.com/open-telemetry/opentelemetry-demo/pull/435))
+* Update cartservice Dockerfile to support ARM64
+([#439](https://github.com/open-telemetry/opentelemetry-demo/pull/439))

src/cartservice/src/Dockerfile

@@ -20,13 +20,16 @@ WORKDIR /usr/src/app/
 COPY ./src/cartservice/ ./
 COPY ./pb/ ./src/protos/
 
-RUN dotnet restore ./src/cartservice.csproj -r linux-musl-x64
-RUN dotnet publish ./src/cartservice.csproj -p:PublishSingleFile=true -r linux-musl-x64 --self-contained true -p:PublishTrimmed=True -p:TrimMode=Link -c Release -o /cartservice --no-restore
+RUN \
+  RUNTIME_IDENTIIFER=linux-musl-x64; \
+  if [ "$(uname -m)" = "aarch64" ]; then RUNTIME_IDENTIIFER=linux-musl-arm64; fi; \
+  dotnet restore ./src/cartservice.csproj -r $RUNTIME_IDENTIIFER && \
+  dotnet publish ./src/cartservice.csproj -p:PublishSingleFile=true -r $RUNTIME_IDENTIIFER --self-contained true -p:PublishTrimmed=True -p:TrimMode=Link -c Release -o /cartservice --no-restore
 
 # -----------------------------------------------------------------------------
 
 # https://mcr.microsoft.com/v2/dotnet/runtime-deps/tags/list
-FROM mcr.microsoft.com/dotnet/runtime-deps:6.0.5-alpine3.15-amd64
+FROM mcr.microsoft.com/dotnet/runtime-deps:6.0.5-alpine3.15
 
 WORKDIR /usr/src/app/
 COPY --from=builder /cartservice/ ./