Prevent compiling the whole project on each commit.

Putting the git information into a generated sourcefile prevents
recompiling the whole project after each commit.

include/__compiled_constants.h

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#pragma once
+
+// The referenced values are generated by pio-scripts/auto_firmware_version.py
+
+
+extern const char *__COMPILED_GIT_HASH__;
+// extern const char *__COMPILED_DATE_TIME_UTC_STR__;

pio-scripts/auto_firmware_version.py

@@ -2,6 +2,7 @@
 #
 # Copyright (C) 2022 Thomas Basler and others
 #
+import os
 import pkg_resources
 
 Import("env")
@@ -15,15 +16,64 @@ if missing_pkgs:
 
 from dulwich import porcelain
 
-def get_firmware_specifier_build_flag():
+
+def updateFileIfChanged(filename, content):
+    mustUpdate = True
+    try:
+        fp = open(filename, "rb")
+        if fp.read() == content:
+            mustUpdate = False
+        fp.close()
+    except:
+        pass
+    if mustUpdate:
+        fp = open(filename, "wb")
+        fp.write(content)
+        fp.close()
+    return mustUpdate
+
+
+def get_build_version():
     try:
         build_version = porcelain.describe('.')  # '.' refers to the repository root dir
     except:
         build_version = "g0000000"
-    build_flag = "-D AUTO_GIT_HASH=\\\"" + build_version + "\\\""
     print ("Firmware Revision: " + build_version)
+    return build_version
+
+
+def get_firmware_specifier_build_flag():
+    build_version = get_build_version()
+    build_flag = "-D AUTO_GIT_HASH=\\\"" + build_version + "\\\""
     return (build_flag)
 
-env.Append(
+
+def do_main():
+    if 0:
+        # this results in a full recompilation of the whole project after each commit
+        env.Append(
             BUILD_FLAGS=[get_firmware_specifier_build_flag()]
-)
+        )
+    else:
+        # we just create a .c file containing the needed datas
+        targetfile = os.path.join(env.subst("$BUILD_DIR"), "__compiled_constants.c")
+        lines = ""
+        lines += "/* Generated file within build process - Do NOT edit */\n"
+
+        if 0:
+            # Add the current date and time as string in UTC timezone
+            from datetime import datetime, timezone
+            now = datetime.now(tz=timezone.utc)
+            COMPILED_DATE_TIME_UTC_STR = now.strftime("%Y/%m/%d %H:%M:%S")
+            lines += 'const char *__COMPILED_DATE_TIME_UTC_STR__ = "%s";\n' % (COMPILED_DATE_TIME_UTC_STR)
+
+        if 1:
+            # Add the description of the current git revision
+            lines += 'const char *__COMPILED_GIT_HASH__ = "%s";\n' % (get_build_version())
+
+        updateFileIfChanged(targetfile, bytes(lines, "utf-8"))
+
+        # Add the created file to the buildfiles - platformio knows how to handle *.c files
+        env.AppendUnique(PIOBUILDFILES=[targetfile])
+
+do_main()

src/MqttHandleHass.cpp

@@ -8,6 +8,7 @@
 #include "NetworkSettings.h"
 #include "Utils.h"
 #include "defaults.h"
+#include "__compiled_constants.h"
 
 MqttHandleHassClass MqttHandleHass;
 
@@ -380,7 +381,7 @@ void MqttHandleHassClass::createInverterInfo(JsonDocument& root, std::shared_ptr
         getDtuUrl(),
         "OpenDTU",
         inv->typeName(),
-        AUTO_GIT_HASH,
+        __COMPILED_GIT_HASH__,
         getDtuUniqueId());
 }
 
@@ -393,7 +394,7 @@ void MqttHandleHassClass::createDtuInfo(JsonDocument& root)
         getDtuUrl(),
         "OpenDTU",
         "OpenDTU",
-        AUTO_GIT_HASH);
+        __COMPILED_GIT_HASH__);
 }
 
 void MqttHandleHassClass::createDeviceInfo(

src/NetworkSettings.cpp

@@ -10,6 +10,7 @@
 #include "defaults.h"
 #include <ESPmDNS.h>
 #include <ETH.h>
+#include "__compiled_constants.h"
 
 NetworkSettingsClass::NetworkSettingsClass()
     : _loopTask(TASK_IMMEDIATE, TASK_FOREVER, std::bind(&NetworkSettingsClass::loop, this))
@@ -136,7 +137,7 @@ void NetworkSettingsClass::handleMDNS()
 
         MDNS.addService("http", "tcp", 80);
         MDNS.addService("opendtu", "tcp", 80);
-        MDNS.addServiceTxt("opendtu", "tcp", "git_hash", AUTO_GIT_HASH);
+        MDNS.addServiceTxt("opendtu", "tcp", "git_hash", __COMPILED_GIT_HASH__);
 
         MessageOutput.println("done");
     } else {

src/WebApi_prometheus.cpp

@@ -9,6 +9,7 @@
 #include "NetworkSettings.h"
 #include "WebApi.h"
 #include <Hoymiles.h>
+#include "__compiled_constants.h"
 
 void WebApiPrometheusClass::init(AsyncWebServer& server, Scheduler& scheduler)
 {
@@ -29,7 +30,7 @@ void WebApiPrometheusClass::onPrometheusMetricsGet(AsyncWebServerRequest* reques
         stream->print("# HELP opendtu_build Build info\n");
         stream->print("# TYPE opendtu_build gauge\n");
         stream->printf("opendtu_build{name=\"%s\",id=\"%s\",version=\"%d.%d.%d\"} 1\n",
-            NetworkSettings.getHostname().c_str(), AUTO_GIT_HASH, CONFIG_VERSION >> 24 & 0xff, CONFIG_VERSION >> 16 & 0xff, CONFIG_VERSION >> 8 & 0xff);
+            NetworkSettings.getHostname().c_str(), __COMPILED_GIT_HASH__, CONFIG_VERSION >> 24 & 0xff, CONFIG_VERSION >> 16 & 0xff, CONFIG_VERSION >> 8 & 0xff);
 
         stream->print("# HELP opendtu_platform Platform info\n");
         stream->print("# TYPE opendtu_platform gauge\n");

src/WebApi_sysstatus.cpp

@@ -11,10 +11,7 @@
 #include <Hoymiles.h>
 #include <LittleFS.h>
 #include <ResetReason.h>
-
+#include "__compiled_constants.h"
-#ifndef AUTO_GIT_HASH
-#define AUTO_GIT_HASH ""
-#endif
 
 void WebApiSysstatusClass::init(AsyncWebServer& server, Scheduler& scheduler)
 {
@@ -64,7 +61,7 @@ void WebApiSysstatusClass::onSystemStatus(AsyncWebServerRequest* request)
     char version[16];
     snprintf(version, sizeof(version), "%d.%d.%d", CONFIG_VERSION >> 24 & 0xff, CONFIG_VERSION >> 16 & 0xff, CONFIG_VERSION >> 8 & 0xff);
     root["config_version"] = version;
-    root["git_hash"] = AUTO_GIT_HASH;
+    root["git_hash"] = __COMPILED_GIT_HASH__;
     root["pioenv"] = PIOENV;
 
     root["uptime"] = esp_timer_get_time() / 1000000;