Create a layer for the opentelemetrt php extension

 * https://github.com/open-telemetry/opentelemetry-php-instrumentation

layers/opentelemetry/Dockerfile

@@ -0,0 +1,17 @@
+# https://github.com/brefphp/extra-php-extensions/blob/master/layers/yaml/Dockerfile
+
+ARG PHP_VERSION
+ARG BREF_VERSION
+FROM bref/build-php-$PHP_VERSION:$BREF_VERSION AS ext
+
+RUN MAKEFLAGS="-j $(nproc)" && pecl install opentelemetry > /dev/null
+RUN cp `php-config --extension-dir`/opentelemetry.so /tmp/opentelemetry.so
+RUN strip --strip-debug /tmp/opentelemetry.so
+RUN echo 'extension=opentelemetry.so' > /tmp/ext.ini
+
+# Build the final image with just the files we need
+FROM scratch
+
+# Copy things we installed to the final image
+COPY --from=ext /tmp/opentelemetry.so /opt/bref/extensions/opentelemetry.so
+COPY --from=ext /tmp/ext.ini /opt/bref/etc/php/conf.d/ext-opentelemetry.ini

layers/opentelemetry/config.json

@@ -0,0 +1,7 @@
+{
+    "php": [
+        "80",
+        "81",
+        "82"
+    ]
+}

layers/opentelemetry/test.php

@@ -0,0 +1,8 @@
+<?php
+
+if (!function_exists($function =   "OpenTelemetry\Instrumentation\hook")) {
+    echo sprintf('FAIL: Function "%s" does not exist.', $function).PHP_EOL;
+    exit(1);
+}
+
+exit(0);