feat: custom Dash0 injector

images/instrumentation/Dockerfile

@@ -1,6 +1,15 @@
+# build injector
+FROM ubuntu:24.04 AS build-injector
+
+RUN apt-get update && apt-get install build-essential -y && apt-get autoremove -y && apt-get autoclean -y
+
+COPY ./injector/src /dash0-init-container/injector
+WORKDIR /dash0-init-container/injector
+RUN gcc -shared -nostdlib -fPIC -Wl,--version-script=dash0_injector.exports.map dash0_injector.c -o dash0_injector.so
+
 # build Node.js artifacts
 FROM node:20.13.1-alpine3.19 AS build-node.js
-RUN mkdir -p /dash0-init-container/instrumentation/node.js
+RUN mkdir -p /instrumentation/node.js
 WORKDIR /dash0-init-container/instrumentation/node.js
 COPY node.js/package* .
 COPY node.js/dash0hq-opentelemetry-*.tgz .
@@ -17,6 +26,7 @@ COPY copy-instrumentation.sh /
 
 # copy node.js artifacts
 RUN mkdir -p /dash0-init-container/instrumentation
+COPY --from=build-injector /dash0-init-container/injector/dash0_injector.so /dash0-init-container/injector/dash0_injector.so
 COPY --from=build-node.js /dash0-init-container/instrumentation/node.js /dash0-init-container/instrumentation/node.js
 
 WORKDIR /

images/instrumentation/injector/src/dash0_injector.c

@@ -0,0 +1,109 @@
+#include <unistd.h>
+#include <stdint.h>
+
+#define ALIGN (sizeof(size_t))
+#define UCHAR_MAX 255
+#define ONES ((size_t)-1/UCHAR_MAX)
+#define HIGHS (ONES * (UCHAR_MAX/2+1))
+#define HASZERO(x) ((x)-ONES & ~(x) & HIGHS)
+
+#define NODE_OPTIONS_ENV_VAR_NAME "NODE_OPTIONS"
+#define NODE_OPTIONS_DASH0_REQUIRE "--require /__dash0__/instrumentation/node.js/node_modules/@dash0hq/opentelemetry"
+
+extern char **__environ;
+
+size_t __strlen(const char *s)
+{
+	const char *a = s;
+	const size_t *w;
+	for (; (uintptr_t)s % ALIGN; s++) if (!*s) return s-a;
+	for (w = (const void *)s; !HASZERO(*w); w++);
+	for (s = (const void *)w; *s; s++);
+	return s-a;
+}
+
+char *__strchrnul(const char *s, int c)
+{
+	size_t *w, k;
+
+	c = (unsigned char)c;
+	if (!c) return (char *)s + __strlen(s);
+
+	for (; (uintptr_t)s % ALIGN; s++)
+		if (!*s || *(unsigned char *)s == c) return (char *)s;
+	k = ONES * c;
+	for (w = (void *)s; !HASZERO(*w) && !HASZERO(*w^k); w++);
+	for (s = (void *)w; *s && *(unsigned char *)s != c; s++);
+	return (char *)s;
+}
+
+char *__strcpy(char *restrict dest, const char *restrict src)
+{
+	const unsigned char *s = src;
+	unsigned char *d = dest;
+	while ((*d++ = *s++));
+	return dest;
+}
+
+char *__strcat(char *restrict dest, const char *restrict src)
+{
+	__strcpy(dest + __strlen(dest), src);
+	return dest;
+}
+
+int __strcmp(const char *l, const char *r)
+{
+	for (; *l==*r && *l; l++, r++);
+	return *(unsigned char *)l - *(unsigned char *)r;
+}
+
+int __strncmp(const char *_l, const char *_r, size_t n)
+{
+	const unsigned char *l=(void *)_l, *r=(void *)_r;
+	if (!n--) return 0;
+	for (; *l && *r && n && *l == *r ; l++, r++, n--);
+	return *l - *r;
+}
+
+char *__getenv(const char *name)
+{
+	size_t l = __strchrnul(name, '=') - name;
+	if (l && !name[l] && __environ)
+		for (char **e = __environ; *e; e++)
+			if (!__strncmp(name, *e, l) && l[*e] == '=')
+				return *e + l+1;
+	return 0;
+}
+
+/*
+ * Buffers of statically-allocated memory that we can use to safely return to
+ * the program manipulated values of env vars without dynamic allocations.
+ */
+char val1[1012];
+char val2[1012];
+
+char *getenv(const char *name)
+{
+    char *origValue = __getenv(name);
+    int l = __strlen(name);
+
+    char *nodeOptionsVarName = NODE_OPTIONS_ENV_VAR_NAME;
+    if (__strcmp(name, nodeOptionsVarName) == 0)
+    {
+        if (__strlen(val1) == 0)
+        {
+            if (origValue != NULL)
+            {
+                __strcat(val1, origValue);
+                __strcat(val1, " ");
+            }
+
+            char *nodeOptionsDash0Require = NODE_OPTIONS_DASH0_REQUIRE;
+            __strcat(val1, nodeOptionsDash0Require);
+        }
+
+        return val1;
+    }
+
+    return origValue;
+}

images/instrumentation/injector/src/dash0_injector.exports.map

@@ -0,0 +1,6 @@
+{
+    global:
+        getenv;
+    local:
+        *;
+};

images/instrumentation/injector/test/node/Dockerfile

@@ -0,0 +1,13 @@
+ARG base_image
+ARG instr_image
+
+FROM ${instr_image} AS instr
+
+FROM ${base_image}
+
+# TODO Normalize node.js path
+
+COPY ./test-cases /test-cases
+
+COPY --from=instr /dash0-init-container /__dash0__
+ENV LD_PRELOAD=/__dash0__/injector/dash0_injector.so

images/instrumentation/injector/test/node/base-images

@@ -0,0 +1,10 @@
+# One base image per line
+node:22-alpine
+node:22-bookworm
+node:22-bullseye
+node:20-alpine
+node:20-bookworm
+node:20-bullseye
+node:18-alpine
+node:18-bookworm
+node:18-bullseye

images/instrumentation/injector/test/node/test-cases/node-options-includes-dash0-require/package.json

@@ -0,0 +1,3 @@
+{
+    "name": "@dash0/injector_tests_node-options-includes-dash0-require"
+}

images/instrumentation/injector/test/node/test-cases/node-options-includes-dash0-require/server.js

@@ -0,0 +1,6 @@
+const nodeOptions = process.env["NODE_OPTIONS"] || "";
+
+if (!nodeOptions.includes("--require /__dash0__/instrumentation/node.js/node_modules/@dash0hq/opentelemetry")) {
+    console.error(`No Dash0 distro require found in NODE_OPTIONS value: '${nodeOptions}'`)
+    process.exit(1);
+}

images/instrumentation/injector/test/test.sh

@@ -0,0 +1,53 @@
+#/bin/env bash
+
+readonly script_dir=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+
+function run_tests () {
+    local runtime="${1}"
+    local docker_image="${2}"
+
+    for t in ${script_dir}/${runtime}/test-cases/*/ ; do
+        test=$(basename $(realpath "${t}"))
+        printf '%s' "Test '${test}' " | sed 's/^/  /' # `echo -n` does not work on Mac OS
+        tempfile=$(mktemp)
+        docker run ${docker_image} "npm" "start" "--prefix" "/test-cases/${test}" > ${tempfile} 2>&1
+        if [ $? -eq 0 ]; then
+            echo OK
+        else
+            echo FAIL
+            echo 'Output (stdout + stderr):'
+            cat ${tempfile} | sed 's/^/    /'
+        fi
+        rm ${tempfile}
+    done
+}
+
+# Build instr image
+instr_image="${1}"
+
+if [ -z "${instr_image}" ]; then    
+    instr_image="dash0-instrumentation:test-latest"
+    echo "Building instrumentation image '${instr_image}' (no instrumentation image tag provided in input)"
+
+    tempfile=$(mktemp)
+    if ! docker build ../.. -t "${instr_image}" > ${tempfile} 2>&1; then
+        echo "Failed to build the instrumentation image:"
+        cat ${tempfile} | sed 's/^/  /'
+    fi
+    rm ${tempfile}
+fi
+
+# Run tests
+for r in ${script_dir}/*/ ; do
+    runtime=$(basename $(realpath "${r}"))
+    echo "Runtime '${runtime}'"
+    grep '^[^#;]' "${script_dir}/${runtime}/base-images" | while read -r base_image ; do
+        echo "Base image '${base_image}'" | sed 's/^/  /'
+        build_output=$(docker build "${script_dir}/${runtime}" --build-arg "instr_image=${instr_image}" --build-arg "base_image=${base_image}" -t "test-${runtime}:latest" 2>&1 | sed 's/^/    /')
+        if [ $? -ne 0 ]; then
+            echo "${build_output}"
+            exit 1
+        fi
+        run_tests "${runtime}" "test-${runtime}:latest" | sed 's/^/  /'
+    done
+done