otel: add build tooling to include otel code

Adds the --otel flag to the configure command and the various build time
variables and checks that are needed in this flow.

It also includes the nxt_otel.c and nxt_otel.h files that are needed for
the rest of Unit to talk to the compiled static library that's generated
from the rust crate.

Signed-off-by: Ava Hahn <a.hahn@f5.com>
Co-authored-by: Gabor Javorszky <g.javorszky@f5.com>
Signed-off-by: Gabor Javorszky <g.javorszky@f5.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/auto/otel b/auto/otel
new file mode 100644
index 00000000..654c45ec
--- /dev/null
+++ b/auto/otel
@@ -0,0 +1,54 @@
+
+# Copyright (C) NGINX, Inc.
+
+if [ $NXT_OTEL = YES ]; then
+
+    $echo "checking for OTEL requirements:"
+
+    $echo -n "  - checking for rust compiler ... "
+    if [ -z $(which rustc 2>/dev/null) ]; then
+        $echo "not found"
+        exit 1;
+    fi
+    $echo "found"
+
+    $echo -n "  - checking for cargo ... "
+    if [ -z $(which cargo 2>/dev/null) ]; then
+        $echo "not found."
+        exit 1;
+    fi
+    $echo "found"
+
+    $echo -n "  - "
+
+    nxt_feature="OpenSSL library"
+    nxt_feature_run=yes
+    nxt_feature_incs=
+    nxt_feature_libs="-lssl -lcrypto"
+    nxt_feature_test="#include <openssl/ssl.h>
+
+                      int main(void) {
+                          SSL_library_init();
+                          return 0;
+                      }"
+    . auto/feature
+
+    if [ ! $nxt_found = yes ]; then
+        $echo
+        $echo $0: error: OpenTelemetry support requires OpenSSL.
+        $echo
+        exit 1;
+    fi
+
+    NXT_OTEL_LIBS="-lssl -lcrypto"
+    if [ $(which pkg-config) ]; then
+        NXT_OTEL_LIBS="$(pkg-config openssl --cflags --libs)"
+    fi
+    cat << END >> $NXT_AUTO_CONFIG_H
+
+#ifndef NXT_HAVE_OTEL
+#define NXT_HAVE_OTEL 1
+#endif
+
+END
+fi