Support GCC-10 in CI and prom,promhttp,promtest (#25)

Co-authored-by: Eldar Yusupov <eyusupov@gmail.com>

23 files changed, 187 insertions, 90 deletions

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 75bc551..513f47d 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -5,6 +5,16 @@ on:
   - pull_request
 
 jobs:
+  ubuntu-20-04:
+    name: ubuntu-20-04
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: test
+        env:
+          DOCKER_IMAGE: ubuntu:20.04
+          CI: 1
+        run: make
   ubuntu-18-04:
     name: ubuntu-18-04
     runs-on: ubuntu-latest
@@ -13,6 +23,7 @@ jobs:
       - name: test
         env:
           DOCKER_IMAGE: ubuntu:18.04
+          CI: 1
         run: make
   ubuntu-16-04:
     name: ubuntu-16-04
@@ -22,6 +33,7 @@ jobs:
       - name: test
         env:
           DOCKER_IMAGE: ubuntu:16.04
+          CI: 1
         run: make
   debian-buster:
     name: debian-buster
@@ -31,6 +43,7 @@ jobs:
       - name: test
         env:
           DOCKER_IMAGE: debian:buster
+          CI: 1
         run: make
   debian-stretch:
     name: debian-stretch
@@ -40,6 +53,7 @@ jobs:
       - name: test
         env:
           DOCKER_IMAGE: debian:stretch
+          CI: 1
         run: make
   debian-jessie:
     name: debian-jessie
@@ -49,4 +63,5 @@ jobs:
       - name: test
         env:
           DOCKER_IMAGE: debian:jessie
+          CI: 1
         run: make
\ No newline at end of file
diff --git a/auto b/auto
index 120d4e2..3adb4be 100755
--- a/auto
+++ b/auto
@@ -12,6 +12,9 @@ fi
 
 export PROJECT_ROOT=$(pushd $(dirname $0) > /dev/null; echo $PWD; popd > /dev/null)
 export DOCKER_IMAGE
+export CI=${CI:=0}
+export CC=/usr/bin/gcc
+
 PROGRAM_NAME="$(basename $0)"
 
 usage(){
diff --git a/autolib/cmd/dev b/autolib/cmd/dev
index bcbf35f..8025993 100755
--- a/autolib/cmd/dev
+++ b/autolib/cmd/dev
@@ -75,6 +75,9 @@ run(){
   args+=(--security-opt seccomp=unconfined)   # Required for debugging
   args+=(--publish $DOCKER_PORT:$DOCKER_PORT) # map DOCKER_PORT to the host
   args+=(--rm)                                # Remove when done
+  if (( ${CI} == 0 )); then
+    args+=(--tty)
+  fi
 
   echo ${args[@]}
   docker run ${args[@]} prometheus-client-c-dev ${DOCKER_EXEC} ${DOCKER_EXEC_ARGS[@]}
@@ -103,4 +106,19 @@ main(){
   run $@; exit $?
 }
 
-[[ $BASH_SOURCE == $0 ]] && main $@
\ No newline at end of file
+[[ $BASH_SOURCE == $0 ]] && main $@
+
+#  curl -L -o /tmp/gcc-${GCC_VERSION}.tar.xz https://ftpmirror.gnu.org/gcc/gcc-${GCC_VERSION}/gcc-${GCC_VERSION}.tar.xz && \
+#     tar xf /tmp/gcc-${GCC_VERSION}.tar.xz -C /tmp && \
+#     rm -rf /tmp/gcc-${GCC_VERSION}.tar.xz && \
+#     cd /tmp/gcc-${GCC_VERSION} && \
+#       contrib/download_prerequisites && \
+#       ./configure -v --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu --prefix=/usr/local/gcc --enable-checking=release --enable-languages=c --disable-multilib && \
+#       make && \
+#       make install-strip && \
+#     cd $OLDPWD && \
+#     echo 'export PATH=/usr/local/gcc/bin:$PATH' >> /root/.bashrc && \
+#     echo 'LD_LIBRARY_PATH=/usr/local/gcc/lib64:$LD_LIBRARY_PATH' >> /root/.bashrc && \
+#     curl -sL https://github.com/Kitware/CMake/releases/download/v3.14.5/cmake-${CMAKE_VERSION}-Linux-x86_64.tar.gz | tar xzf - -C /opt && \
+#     cp /opt/cmake-${CMAKE_VERSION}-Linux-x86_64/bin/* /usr/local/bin/ && \
+#     cp -R /opt/cmake-${CMAKE_VERSION}-Linux-x86_64/share/cmake-3.14 /usr/local/share/ && \
\ No newline at end of file
diff --git a/autolib/docker.sh b/autolib/docker.sh
index bfef40d..9834c4b 100644
--- a/autolib/docker.sh
+++ b/autolib/docker.sh
@@ -5,11 +5,46 @@ source "${lib}/output.sh"
 
 PROJECT_ROOT=$(pushd "$(dirname ${BASH_SOURCE[0]})/.." > /dev/null; echo $PWD; popd > /dev/null)
 
-autolib_debian_template(){
+autolib_new_debian_template(){
   cat <<'EOF'
 FROM __DOCKER_IMAGE__
 
-RUN apt-get update && \
+RUN set -x && \
+    apt-get update && \
+    apt-get install -y apt-utils software-properties-common && \
+    add-apt-repository ppa:ubuntu-toolchain-r/test && \
+    apt-get update -y && \
+    apt-get install -y curl tar build-essential git pkg-config gdb valgrind gcc-10 libmicrohttpd-dev doxygen graphviz && \
+    rm -f /usr/bin/gcc && \
+    ln -s /usr/bin/gcc-10 /usr/bin/gcc && \
+    curl -sL https://github.com/Kitware/CMake/releases/download/v3.14.5/cmake-3.14.5-Linux-x86_64.tar.gz | tar xzf - -C /opt && \
+    cp /opt/cmake-3.14.5-Linux-x86_64/bin/* /usr/local/bin/ && \
+    cp -R /opt/cmake-3.14.5-Linux-x86_64/share/cmake-3.14 /usr/local/share/ && \
+    curl -sL https://dl.google.com/go/go1.13.1.linux-amd64.tar.gz 2> /dev/null | tar xzf - -C /usr/local && \
+    mkdir -p /gopath/{src,bin} && \
+    printf 'export GOPATH=/gopath\nexport PATH=$PATH:/usr/local/go/bin:/gopath/bin\n' > /root/.bash_profile && \
+    printf '#!/usr/bin/env bash\nsource /root/.bash_profile\nexec /bin/bash $@\n' > /entrypoint && \
+    chmod +x /entrypoint && \
+    GOPATH=/gopath /usr/local/go/bin/go get github.com/prometheus/prom2json && \
+    GOPATH=/gopath /usr/local/go/bin/go install github.com/prometheus/prom2json/cmd/prom2json && \
+    GOPATH=/gopath /usr/local/go/bin/go get github.com/git-chglog/git-chglog && \
+    GOPATH=/gopath /usr/local/go/bin/go install github.com/git-chglog/git-chglog/cmd/git-chglog && \
+    rm -rf /var/lib/apt/lists/*
+
+WORKDIR /code
+ENTRYPOINT ["/entrypoint"]
+
+EOF
+}
+
+autolib_old_debian_template(){
+  cat <<'EOF'
+FROM __DOCKER_IMAGE__
+
+ENV GCC_VERSION 10.1.0
+
+RUN set -x && \
+    apt-get update && \
     apt-get install -y apt-utils && \
     apt-get install -y curl tar build-essential git pkg-config gdb valgrind gcc libmicrohttpd-dev doxygen graphviz && \
     curl -sL https://github.com/Kitware/CMake/releases/download/v3.14.5/cmake-3.14.5-Linux-x86_64.tar.gz | tar xzf - -C /opt && \
@@ -36,14 +71,20 @@ autolib_write_dockerfile(){
   local docker_image="$1"
   local r
   case "$docker_image" in
-    ( ubuntu:18.04 | ubuntu:16.04 | debian:buster | debian:stretch | debian:jessie ) {
-      autolib_debian_template | sed "s/__DOCKER_IMAGE__/$docker_image/g" > ${PROJECT_ROOT}/docker/Dockerfile || {
+    ( ubuntu:20.04 | ubuntu:18.04 ) {
+       autolib_new_debian_template | sed "s/__DOCKER_IMAGE__/$docker_image/g" > ${PROJECT_ROOT}/docker/Dockerfile || {
+        r=$?
+        autolib_output_error "failed to generate dockerfile"
+        return $r
+      }
+    } ;;
+    ( ubuntu:16.04 | debian:buster | debian:stretch | debian:jessie ) {
+      autolib_old_debian_template | sed "s/__DOCKER_IMAGE__/$docker_image/g" > ${PROJECT_ROOT}/docker/Dockerfile || {
         r=$?
         autolib_output_error "failed to generate dockerfile"
         return $r
       }
     } ;;
-
     ( * ) {
       r=1
       autolib_output_error "unsupported DOCKER_IMAGE: $docker_image"
diff --git a/prom/CMakeLists.txt b/prom/CMakeLists.txt
index b99cd75..6ed20b6 100644
--- a/prom/CMakeLists.txt
+++ b/prom/CMakeLists.txt
@@ -106,6 +106,7 @@ include(FindThreads)
 add_library(prom SHARED)
 
 target_compile_options(prom PRIVATE "-Werror" "-Wuninitialized" "-Wall" "-Wno-unused-label" "-std=gnu11")
+target_compile_options(prom PUBLIC "-Werror" "-Wuninitialized" "-Wall" "-Wno-unused-label" "-std=gnu11")
 
 target_include_directories(
     prom
diff --git a/prom/include/prom_collector_registry.h b/prom/include/prom_collector_registry.h
index 8e70c92..974aa24 100644
--- a/prom/include/prom_collector_registry.h
+++ b/prom/include/prom_collector_registry.h
@@ -34,7 +34,7 @@ typedef struct prom_collector_registry prom_collector_registry_t;
  * @brief Initialize the default registry by calling prom_collector_registry_init within your program. You MUST NOT
  * modify this value.
  */
-prom_collector_registry_t *PROM_COLLECTOR_REGISTRY_DEFAULT;
+extern prom_collector_registry_t *PROM_COLLECTOR_REGISTRY_DEFAULT;
 
 /**
  * @brief Initializes the default collector registry and enables metric collection on the executing process
@@ -120,4 +120,4 @@ const char* prom_collector_registry_bridge(prom_collector_registry_t *self);
 int prom_collector_registry_validate_metric_name(prom_collector_registry_t *self,
                                                                 const char *metric_name);
 
-#endif // PROM_H
\ No newline at end of file
+#endif // PROM_H
diff --git a/prom/include/prom_histogram_buckets.h b/prom/include/prom_histogram_buckets.h
index ec850e2..24afe22 100644
--- a/prom/include/prom_histogram_buckets.h
+++ b/prom/include/prom_histogram_buckets.h
@@ -41,7 +41,7 @@ prom_histogram_buckets_t* prom_histogram_buckets_new(size_t count, double bucket
 /**
  * @brief the default histogram buckets: .005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10
  */
-prom_histogram_buckets_t *prom_histogram_default_buckets;
+extern prom_histogram_buckets_t *prom_histogram_default_buckets;
 
 /**
  *@brief Construct a linearly sized prom_histogram_buckets_t*
diff --git a/prom/src/prom_collector_registry.c b/prom/src/prom_collector_registry.c
index 166c239..aa69489 100644
--- a/prom/src/prom_collector_registry.c
+++ b/prom/src/prom_collector_registry.c
@@ -37,6 +37,7 @@
 #include "prom_process_limits_i.h"
 #include "prom_string_builder_i.h"
 
+prom_collector_registry_t *PROM_COLLECTOR_REGISTRY_DEFAULT;
 
 prom_collector_registry_t* prom_collector_registry_new(const char *name)
 {
diff --git a/prom/src/prom_histogram_buckets.c b/prom/src/prom_histogram_buckets.c
index ecfd00c..f63f7ae 100644
--- a/prom/src/prom_histogram_buckets.c
+++ b/prom/src/prom_histogram_buckets.c
@@ -25,6 +25,8 @@
 #include "prom_assert.h"
 #include "prom_log.h"
 
+prom_histogram_buckets_t *prom_histogram_default_buckets;
+
 prom_histogram_buckets_t* prom_histogram_buckets_new(size_t count, double bucket, ...) {
   prom_histogram_buckets_t *self = (prom_histogram_buckets_t*) prom_malloc(sizeof(prom_histogram_buckets_t));
   double *upper_bounds = (double*) prom_malloc(sizeof(double)*count);
@@ -98,4 +100,4 @@ int prom_histogram_buckets_destroy(prom_histogram_buckets_t *self) {
 size_t prom_histogram_buckets_count(prom_histogram_buckets_t *self) {
   PROM_ASSERT(self != NULL);
   return self->count;
-}
\ No newline at end of file
+}
diff --git a/prom/src/prom_metric_t.h b/prom/src/prom_metric_t.h
index cab93d6..17e0847 100644
--- a/prom/src/prom_metric_t.h
+++ b/prom/src/prom_metric_t.h
@@ -42,7 +42,7 @@ typedef enum prom_metric_type {
 /**
  * @brief API PRIVATE Maps metric type constants to human readable string values
  */
-char *prom_metric_type_map[4];
+extern char *prom_metric_type_map[4];
 
 /**
  * @brief API PRIVATE An opaque struct to users containing metric metadata; one or more metric samples; and a metric formatter
diff --git a/prom/src/prom_process_fds.c b/prom/src/prom_process_fds.c
index c8a5f4e..4451782 100644
--- a/prom/src/prom_process_fds.c
+++ b/prom/src/prom_process_fds.c
@@ -30,6 +30,8 @@
 #include "prom_log.h"
 #include "prom_process_fds_t.h"
 
+prom_gauge_t *prom_process_open_fds;
+
 int prom_process_fds_count(const char *path) {
   int count = 0;
   int r = 0;
@@ -74,4 +76,4 @@ int prom_process_fds_init(void) {
     0, NULL
   );
   return 0;
-}
\ No newline at end of file
+}
diff --git a/prom/src/prom_process_fds_t.h b/prom/src/prom_process_fds_t.h
index d7f3e2b..e0e73c6 100644
--- a/prom/src/prom_process_fds_t.h
+++ b/prom/src/prom_process_fds_t.h
@@ -19,6 +19,6 @@
 #ifndef PROM_PROESS_FDS_T_H
 #define PROM_PROESS_FDS_T_H
 
-prom_gauge_t *prom_process_open_fds;
+extern prom_gauge_t *prom_process_open_fds;
 
-#endif // PROM_PROESS_FDS_T_H
\ No newline at end of file
+#endif // PROM_PROESS_FDS_T_H
diff --git a/prom/src/prom_process_limits.c b/prom/src/prom_process_limits.c
index 685a31c..fcc8649 100644
--- a/prom/src/prom_process_limits.c
+++ b/prom/src/prom_process_limits.c
@@ -49,6 +49,10 @@ typedef enum prom_process_limit_rdp_limit_type {
   PROM_PROCESS_LIMITS_RDP_HARD
 } prom_process_limit_rdp_limit_type_t;
 
+prom_gauge_t *prom_process_virtual_memory_max_bytes;
+prom_gauge_t *prom_process_resident_memory_bytes;
+prom_gauge_t *prom_process_max_fds;
+
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 // prom_process_limits_row_t
 
diff --git a/prom/src/prom_process_limits_t.h b/prom/src/prom_process_limits_t.h
index 9435a8b..b18253d 100644
--- a/prom/src/prom_process_limits_t.h
+++ b/prom/src/prom_process_limits_t.h
@@ -21,10 +21,10 @@
 #include "prom_procfs_t.h"
 
 
-prom_gauge_t *prom_process_open_fds;
-prom_gauge_t *prom_process_max_fds;
-prom_gauge_t *prom_process_virtual_memory_max_bytes;
-prom_gauge_t *prom_process_resident_memory_bytes;
+extern prom_gauge_t *prom_process_open_fds;
+extern prom_gauge_t *prom_process_max_fds;
+extern prom_gauge_t *prom_process_virtual_memory_max_bytes;
+extern prom_gauge_t *prom_process_resident_memory_bytes;
 
 
 typedef struct prom_process_limits_row {
@@ -43,4 +43,4 @@ typedef struct prom_process_limits_current_row {
 
 typedef prom_procfs_buf_t prom_process_limits_file_t;
 
-#endif // PROM_PROCESS_T_H
\ No newline at end of file
+#endif // PROM_PROCESS_T_H
diff --git a/prom/src/prom_process_stat.c b/prom/src/prom_process_stat.c
index 9deb717..7a1833c 100644
--- a/prom/src/prom_process_stat.c
+++ b/prom/src/prom_process_stat.c
@@ -28,6 +28,10 @@
 #include "prom_process_stat_t.h"
 #include "prom_procfs_i.h"
 
+prom_gauge_t *prom_process_cpu_seconds_total;
+prom_gauge_t *prom_process_virtual_memory_bytes;
+prom_gauge_t *prom_process_start_time_seconds;
+
 prom_process_stat_file_t* prom_process_stat_file_new(const char *path) {
   if (path) {
     return prom_procfs_buf_new(path);
@@ -195,4 +199,4 @@ int prom_process_stats_init(void) {
     0, NULL
   );
   return 0;
-}
\ No newline at end of file
+}
diff --git a/prom/src/prom_process_stat_t.h b/prom/src/prom_process_stat_t.h
index e9c6a7c..a26ecda 100644
--- a/prom/src/prom_process_stat_t.h
+++ b/prom/src/prom_process_stat_t.h
@@ -22,9 +22,9 @@
 
 #include "prom_procfs_t.h"
 
-prom_gauge_t *prom_process_cpu_seconds_total;
-prom_gauge_t *prom_process_virtual_memory_bytes;
-prom_gauge_t *prom_process_start_time_seconds;
+extern prom_gauge_t *prom_process_cpu_seconds_total;
+extern prom_gauge_t *prom_process_virtual_memory_bytes;
+extern prom_gauge_t *prom_process_start_time_seconds;
 
 /**
  * @brief Refer to man proc and search for /proc/[pid]/stat
@@ -86,4 +86,4 @@ typedef struct prom_process_stat {
 
 typedef prom_procfs_buf_t prom_process_stat_file_t;
 
-#endif // PROM_PROCESS_STATS_T_H
\ No newline at end of file
+#endif // PROM_PROCESS_STATS_T_H
diff --git a/promhttp/CMakeLists.txt b/promhttp/CMakeLists.txt
index 8283a21..5a14903 100644
--- a/promhttp/CMakeLists.txt
+++ b/promhttp/CMakeLists.txt
@@ -59,6 +59,9 @@ target_sources(
 find_library(prom prom HINTS ${CMAKE_CURRENT_SOURCE_DIR}/../prom/build)
 find_library(microhttpd microhttpd)
 
+target_compile_options(promhttp PRIVATE "-Werror" "-Wuninitialized" "-Wall" "-Wno-unused-label" "-std=gnu11")
+target_compile_options(promhttp PUBLIC "-Werror" "-Wuninitialized" "-Wall" "-Wno-unused-label" "-std=gnu11")
+
 target_link_libraries(promhttp PUBLIC Threads::Threads prom microhttpd)
 
 set(CPACK_PACKAGE_NAME libpromhttp-dev)
diff --git a/promtest/test/promtest_counter.c b/promtest/test/promtest_counter.c
index c57cd56..923c8a2 100644
--- a/promtest/test/promtest_counter.c
+++ b/promtest/test/promtest_counter.c
@@ -14,22 +14,23 @@
  * limitations under the License.
  */
 
+#include "promtest_counter.h"
+
 #include <pthread.h>
 
 #include "parson.h"
-#include "unity.h"
-
 #include "prom.h"
 #include "promhttp.h"
 #include "promtest_helpers.h"
-#include "promtest_counter.h"
-
+#include "unity.h"
 
 static void *promtest_counter_handler(void *data);
 static int promtest_parse_counter_output(const char *output, char **value);
+prom_counter_t *foo_counter;
 
 /**
- * @brief For each thread in a threadpool of 10 we increment a single counter 1 million times
+ * @brief For each thread in a threadpool of 10 we increment a single counter 1
+ * million times
  *
  * The purpose of this test is to check for deadlock and race conditions
  */
@@ -43,21 +44,22 @@ void promtest_counter(void) {
 
   // Start each thread
   for (int i = 0; i < PROMTEST_THREAD_POOL_SIZE; i++) {
-    if (pthread_create(&(thread_pool[i]), NULL, promtest_counter_handler, NULL)) {
+    if (pthread_create(&(thread_pool[i]), NULL, promtest_counter_handler,
+                       NULL)) {
       TEST_FAIL_MESSAGE("failed to create thread");
     }
   }
 
   // Join each thread
   for (int i = 0; i < PROMTEST_THREAD_POOL_SIZE; i++) {
-    if (pthread_join(thread_pool[i], (void**) &(retvals[i]))) {
+    if (pthread_join(thread_pool[i], (void **)&(retvals[i]))) {
       TEST_FAIL_MESSAGE("thread failed to join");
     }
   }
 
   // verify clean exit for each thread
   for (int i = 0; i < PROMTEST_THREAD_POOL_SIZE; i++) {
-    if (*((int *) retvals[i]) != 0) {
+    if (*((int *)retvals[i]) != 0) {
       TEST_FAIL_MESSAGE("thread did not exit properly");
     }
   }
@@ -78,7 +80,7 @@ void promtest_counter(void) {
   }
 
   // Parse the output
-  char *value = (char *) malloc(sizeof(char)*100);
+  char *value = (char *)malloc(sizeof(char) * 100);
   if (promtest_parse_counter_output(output, &value)) {
     TEST_FAIL_MESSAGE("failed to parse output");
   }
@@ -97,22 +99,25 @@ int promtest_counter_setup(void) {
   prom_collector_registry_default_init();
 
   // Set the counter
-  foo_counter = prom_collector_registry_must_register_metric(prom_counter_new(
-    "foo_counter", "counter for foo", 0, NULL
-  ));
+  foo_counter = prom_collector_registry_must_register_metric(
+      prom_counter_new("foo_counter", "counter for foo", 0, NULL));
 
   // Set the collector registry on the handler to the default registry
   promhttp_set_active_collector_registry(NULL);
 
   // Start the HTTP server
-  promtest_daemon = promhttp_start_daemon(MHD_USE_SELECT_INTERNALLY, 8000, NULL, NULL);
+  promtest_daemon =
+      promhttp_start_daemon(MHD_USE_SELECT_INTERNALLY, 8000, NULL, NULL);
 
-  if (promtest_daemon == NULL) return 1;
-  else return 0;
+  if (promtest_daemon == NULL)
+    return 1;
+  else
+    return 0;
 }
 
 int promtest_counter_teardown(void) {
-  // Destroy the default registry. This effectively deallocates all metrics registered to it, including itself
+  // Destroy the default registry. This effectively deallocates all metrics
+  // registered to it, including itself
   prom_collector_registry_destroy(PROM_COLLECTOR_REGISTRY_DEFAULT);
   PROM_COLLECTOR_REGISTRY_DEFAULT = NULL;
 
@@ -122,7 +127,6 @@ int promtest_counter_teardown(void) {
   return 0;
 }
 
-
 /**
  * @brief The entrypoint to a worker thread within the prom_counter_test
  */
@@ -130,9 +134,9 @@ static void *promtest_counter_handler(void *data) {
   for (int i = 0; i < 1000000; i++) {
     prom_counter_inc(foo_counter, NULL);
   }
-  int *retval = (int*) malloc(sizeof(int));
+  int *retval = (int *)malloc(sizeof(int));
   *retval = 0;
-  return (void*) retval;
+  return (void *)retval;
 }
 
 /**
@@ -165,14 +169,14 @@ static int promtest_parse_counter_output(const char *output, char **value) {
     if (samples == NULL) {
       TEST_FAIL_MESSAGE("failed to retrieve metrics from JSON_Object");
     }
-    if (json_array_get_count(samples) < 1){
+    if (json_array_get_count(samples) < 1) {
       TEST_FAIL_MESSAGE("No samples found");
     }
     JSON_Object *sample = json_array_get_object(samples, 0);
     if (sample == NULL) {
       TEST_FAIL_MESSAGE("failed to get metric sample");
     }
-    *value = (char *) json_object_get_string(sample, "value");
+    *value = (char *)json_object_get_string(sample, "value");
     break;
   }
   if (strlen(*value) == 0) {
@@ -180,4 +184,3 @@ static int promtest_parse_counter_output(const char *output, char **value) {
   }
   return 0;
 }
-
diff --git a/promtest/test/promtest_counter.h b/promtest/test/promtest_counter.h
index a8fd719..a94817a 100644
--- a/promtest/test/promtest_counter.h
+++ b/promtest/test/promtest_counter.h
@@ -19,11 +19,11 @@
 #ifndef PROMTEST_COUNTER_H
 #define PROMTEST_COUNTER_H
 
-prom_counter_t *foo_counter;
+extern prom_counter_t *foo_counter;
 
 int promtest_counter_setup(void);
 int promtest_counter_teardown(void);
 
 void promtest_counter(void);
 
-#endif // PROMTEST_COUNTER_H
\ No newline at end of file
+#endif  // PROMTEST_COUNTER_H
\ No newline at end of file
diff --git a/promtest/test/promtest_gauge.c b/promtest/test/promtest_gauge.c
index c33450d..fd6244d 100644
--- a/promtest/test/promtest_gauge.c
+++ b/promtest/test/promtest_gauge.c
@@ -14,22 +14,23 @@
  * limitations under the License.
  */
 
+#include "promtest_gauge.h"
+
 #include <pthread.h>
 
 #include "parson.h"
-#include "unity.h"
-
 #include "prom.h"
 #include "promhttp.h"
 #include "promtest_helpers.h"
-#include "promtest_gauge.h"
-
+#include "unity.h"
 
 static void *promtest_gauge_handler(void *data);
 static int promtest_parse_gauge_output(const char *output, char **value);
+prom_gauge_t *foo_gauge;
 
 /**
- * @brief For each thread in a threadpool of 10 we increment a single gauge 1 million times
+ * @brief For each thread in a threadpool of 10 we increment a single gauge 1
+ * million times
  *
  * The purpose of this test is to check for deadlock and race conditions
  */
@@ -50,14 +51,14 @@ void promtest_gauge(void) {
 
   // Join each thread
   for (int i = 0; i < PROMTEST_THREAD_POOL_SIZE; i++) {
-    if (pthread_join(thread_pool[i], (void**) &(retvals[i]))) {
+    if (pthread_join(thread_pool[i], (void **)&(retvals[i]))) {
       TEST_FAIL_MESSAGE("thread failed to join");
     }
   }
 
   // verify clean exit for each thread
   for (int i = 0; i < PROMTEST_THREAD_POOL_SIZE; i++) {
-    if (*((int *) retvals[i]) != 0) {
+    if (*((int *)retvals[i]) != 0) {
       TEST_FAIL_MESSAGE("thread did not exit properly");
     }
   }
@@ -78,7 +79,7 @@ void promtest_gauge(void) {
   }
 
   // Parse the output
-  char *value = (char *) malloc(sizeof(char)*100);
+  char *value = (char *)malloc(sizeof(char) * 100);
   if (promtest_parse_gauge_output(output, &value)) {
     TEST_FAIL_MESSAGE("failed to parse output");
   }
@@ -97,22 +98,25 @@ int promtest_gauge_setup(void) {
   prom_collector_registry_default_init();
 
   // Set the gauge
-  foo_gauge = prom_collector_registry_must_register_metric(prom_gauge_new(
-    "foo_gauge", "gauge for foo", 0, NULL
-  ));
+  foo_gauge = prom_collector_registry_must_register_metric(
+      prom_gauge_new("foo_gauge", "gauge for foo", 0, NULL));
 
   // Set the collector registry on the handler to the default registry
   promhttp_set_active_collector_registry(NULL);
 
   // Start the HTTP server
-  promtest_daemon = promhttp_start_daemon(MHD_USE_SELECT_INTERNALLY, 8000, NULL, NULL);
+  promtest_daemon =
+      promhttp_start_daemon(MHD_USE_SELECT_INTERNALLY, 8000, NULL, NULL);
 
-  if (promtest_daemon == NULL) return 1;
-  else return 0;
+  if (promtest_daemon == NULL)
+    return 1;
+  else
+    return 0;
 }
 
 int promtest_gauge_teardown(void) {
-  // Destroy the default registry. This effectively deallocates all metrics registered to it, including itself
+  // Destroy the default registry. This effectively deallocates all metrics
+  // registered to it, including itself
   prom_collector_registry_destroy(PROM_COLLECTOR_REGISTRY_DEFAULT);
 
   PROM_COLLECTOR_REGISTRY_DEFAULT = NULL;
@@ -123,7 +127,6 @@ int promtest_gauge_teardown(void) {
   return 0;
 }
 
-
 /**
  * @brief The entrypoint to a worker thread within the prom_gauge_test
  */
@@ -131,9 +134,9 @@ static void *promtest_gauge_handler(void *data) {
   for (int i = 0; i < 1000000; i++) {
     prom_gauge_inc(foo_gauge, NULL);
   }
-  int *retval = (int*) malloc(sizeof(int));
+  int *retval = (int *)malloc(sizeof(int));
   *retval = 0;
-  return (void*) retval;
+  return (void *)retval;
 }
 
 /**
@@ -166,14 +169,14 @@ static int promtest_parse_gauge_output(const char *output, char **value) {
     if (samples == NULL) {
       TEST_FAIL_MESSAGE("failed to retrieve metrics from JSON_Object");
     }
-    if (json_array_get_count(samples) < 1){
+    if (json_array_get_count(samples) < 1) {
       TEST_FAIL_MESSAGE("No samples found");
     }
     JSON_Object *sample = json_array_get_object(samples, 0);
     if (sample == NULL) {
       TEST_FAIL_MESSAGE("failed to get metric sample");
     }
-    *value = (char *) json_object_get_string(sample, "value");
+    *value = (char *)json_object_get_string(sample, "value");
     break;
   }
   if (strlen(*value) == 0) {
@@ -181,4 +184,3 @@ static int promtest_parse_gauge_output(const char *output, char **value) {
   }
   return 0;
 }
-
diff --git a/promtest/test/promtest_gauge.h b/promtest/test/promtest_gauge.h
index 149fbbc..1abcc46 100644
--- a/promtest/test/promtest_gauge.h
+++ b/promtest/test/promtest_gauge.h
@@ -19,11 +19,11 @@
 #ifndef PROMTEST_GAUGE_H
 #define PROMTEST_GAUGE_H
 
-prom_gauge_t *foo_gauge;
+extern prom_gauge_t *foo_gauge;
 
 int promtest_gauge_setup(void);
 int promtest_gauge_teardown(void);
 
 void promtest_gauge(void);
 
-#endif // PROMTEST_GAUGE_H
\ No newline at end of file
+#endif  // PROMTEST_GAUGE_H
\ No newline at end of file
diff --git a/promtest/test/promtest_helpers.c b/promtest/test/promtest_helpers.c
index 01a0da2..e27d7ca 100644
--- a/promtest/test/promtest_helpers.c
+++ b/promtest/test/promtest_helpers.c
@@ -14,15 +14,18 @@
  * limitations under the License.
  */
 
-#include <stdlib.h>
+#include "promtest_helpers.h"
+
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "prom.h"
-#include "promtest_helpers.h"
 
+struct MHD_Daemon *promtest_daemon;
 
 promtest_popen_buf_t *promtest_popen_buf_new(FILE *f) {
-  promtest_popen_buf_t *self = (promtest_popen_buf_t*) malloc(sizeof(promtest_popen_buf_t));
+  promtest_popen_buf_t *self =
+      (promtest_popen_buf_t *)malloc(sizeof(promtest_popen_buf_t));
   self->buf = malloc(32);
   self->size = 32;
   self->allocated = 32;
@@ -31,9 +34,9 @@ promtest_popen_buf_t *promtest_popen_buf_new(FILE *f) {
 }
 
 int promtest_popen_buf_ensure_space(promtest_popen_buf_t *self) {
-  if (self->allocated >= self->size+1) return 0;
-  while (self->allocated < self->size+1) self->allocated <<= 1;
-  self->buf = (char *) prom_realloc(self->buf, self->allocated);
+  if (self->allocated >= self->size + 1) return 0;
+  while (self->allocated < self->size + 1) self->allocated <<= 1;
+  self->buf = (char *)prom_realloc(self->buf, self->allocated);
   return 0;
 }
 
@@ -41,19 +44,16 @@ int promtest_popen_buf_destroy(promtest_popen_buf_t *self) {
   if (self == NULL) {
     return 0;
   }
-  free((void*) self->buf);
+  free((void *)self->buf);
   self->buf = NULL;
-  free((void*) self);
+  free((void *)self);
   self = NULL;
   return 0;
 }
 
-int promtest_popen_buf_read(promtest_popen_buf_t* self) {
-  for (
-    int current_char = fgetc(self->f), i = 0;
-    current_char != EOF;
-    current_char = fgetc(self->f), i++
-  ) {
+int promtest_popen_buf_read(promtest_popen_buf_t *self) {
+  for (int current_char = fgetc(self->f), i = 0; current_char != EOF;
+       current_char = fgetc(self->f), i++) {
     promtest_popen_buf_ensure_space(self);
     self->buf[i] = current_char;
     self->size++;
diff --git a/promtest/test/promtest_helpers.h b/promtest/test/promtest_helpers.h
index 4bdc6a2..b6cb2c3 100644
--- a/promtest/test/promtest_helpers.h
+++ b/promtest/test/promtest_helpers.h
@@ -21,7 +21,7 @@
 
 #define PROMTEST_THREAD_POOL_SIZE 5
 
-struct MHD_Daemon *promtest_daemon;
+extern struct MHD_Daemon *promtest_daemon;
 
 typedef struct promtest_popen_buf {
   char *buf;
@@ -32,9 +32,7 @@ typedef struct promtest_popen_buf {
 
 promtest_popen_buf_t *promtest_popen_buf_new(FILE *f);
 int promtest_popen_buf_destroy(promtest_popen_buf_t *self);
-int promtest_popen_buf_read(promtest_popen_buf_t* self);
+int promtest_popen_buf_read(promtest_popen_buf_t *self);
 int promtest_popen_buf_ensure_space(promtest_popen_buf_t *self);
 
-
-#endif // PROMTEST_HELPERS_H
-
+#endif  // PROMTEST_HELPERS_H