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-rw-r--r--libnetdata/config/Makefile.am9
-rw-r--r--libnetdata/config/README.md48
-rw-r--r--libnetdata/config/appconfig.c588
-rw-r--r--libnetdata/config/appconfig.h136
4 files changed, 781 insertions, 0 deletions
diff --git a/libnetdata/config/Makefile.am b/libnetdata/config/Makefile.am
new file mode 100644
index 0000000..1cb69ed
--- /dev/null
+++ b/libnetdata/config/Makefile.am
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+AUTOMAKE_OPTIONS = subdir-objects
+MAINTAINERCLEANFILES = $(srcdir)/Makefile.in
+
+
+dist_noinst_DATA = \
+ README.md \
+ $(NULL)
diff --git a/libnetdata/config/README.md b/libnetdata/config/README.md
new file mode 100644
index 0000000..f0a27d9
--- /dev/null
+++ b/libnetdata/config/README.md
@@ -0,0 +1,48 @@
+# netdata ini config files
+
+Configuration files `netdata.conf` and `stream.conf` are netdata ini files.
+
+## Motivation
+
+The whole idea came up when we were evaluating the documentation involved
+in maintaining a complex configuration system. Our intention was to give
+configuration options for everything imaginable. But then, documenting all
+these options would require a tremendous amount of time, users would have
+to search through endless pages for the option they need, etc.
+
+We concluded then that **configuring software like that is a waste of time
+and effort**. Of course there must be plenty of configuration options, but
+the implementation itself should require a lot less effort for both the
+developers and the users.
+
+So, we did this:
+
+1. No configuration is required to run netdata
+2. There are plenty of options to tweak
+3. There is minimal documentation (or no at all)
+
+## Why this works?
+
+The configuration file is a `name = value` dictionary with `[sections]`.
+Write whatever you like there as long as it follows this simple format.
+
+Netdata loads this dictionary and then when the code needs a value from
+it, it just looks up the `name` in the dictionary at the proper `section`.
+In all places, in the code, there are both the `names` and their
+`default values`, so if something is not found in the configuration
+file, the default is used. The lookup is made using B-Trees and hashes
+(no string comparisons), so they are super fast. Also the `names` of the
+settings can be `my super duper setting that once set to yes, will turn the world upside down = no`
+- so goodbye to most of the documentation involved.
+
+Next, netdata can generate a valid configuration for the user to edit.
+No need to remember anything or copy and paste settings. Just get the
+configuration from the server (`/netdata.conf` on your netdata server),
+edit it and save it.
+
+Last, what about options you believe you have set, but you misspelled?
+When you get the configuration file from the server, there will be a
+comment above all `name = value` pairs the server does not use.
+So you know that whatever you wrote there, is not used.
+
+[![analytics](https://www.google-analytics.com/collect?v=1&aip=1&t=pageview&_s=1&ds=github&dr=https%3A%2F%2Fgithub.com%2Fnetdata%2Fnetdata&dl=https%3A%2F%2Fmy-netdata.io%2Fgithub%2Flibnetdata%2Fconfig%2FREADME&_u=MAC~&cid=5792dfd7-8dc4-476b-af31-da2fdb9f93d2&tid=UA-64295674-3)]()
diff --git a/libnetdata/config/appconfig.c b/libnetdata/config/appconfig.c
new file mode 100644
index 0000000..9e6a0c0
--- /dev/null
+++ b/libnetdata/config/appconfig.c
@@ -0,0 +1,588 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "../libnetdata.h"
+
+#define CONFIG_FILE_LINE_MAX ((CONFIG_MAX_NAME + CONFIG_MAX_VALUE + 1024) * 2)
+
+// ----------------------------------------------------------------------------
+// definitions
+
+#define CONFIG_VALUE_LOADED 0x01 // has been loaded from the config
+#define CONFIG_VALUE_USED 0x02 // has been accessed from the program
+#define CONFIG_VALUE_CHANGED 0x04 // has been changed from the loaded value or the internal default value
+#define CONFIG_VALUE_CHECKED 0x08 // has been checked if the value is different from the default
+
+struct config_option {
+ avl avl; // the index entry of this entry - this has to be first!
+
+ uint8_t flags;
+ uint32_t hash; // a simple hash to speed up searching
+ // we first compare hashes, and only if the hashes are equal we do string comparisons
+
+ char *name;
+ char *value;
+
+ struct config_option *next; // config->mutex protects just this
+};
+
+struct section {
+ avl avl; // the index entry of this section - this has to be first!
+
+ uint32_t hash; // a simple hash to speed up searching
+ // we first compare hashes, and only if the hashes are equal we do string comparisons
+
+ char *name;
+
+ struct section *next; // gloabl config_mutex protects just this
+
+ struct config_option *values;
+ avl_tree_lock values_index;
+
+ netdata_mutex_t mutex; // this locks only the writers, to ensure atomic updates
+ // readers are protected using the rwlock in avl_tree_lock
+};
+
+
+// ----------------------------------------------------------------------------
+// locking
+
+static inline void appconfig_wrlock(struct config *root) {
+ netdata_mutex_lock(&root->mutex);
+}
+
+static inline void appconfig_unlock(struct config *root) {
+ netdata_mutex_unlock(&root->mutex);
+}
+
+static inline void config_section_wrlock(struct section *co) {
+ netdata_mutex_lock(&co->mutex);
+}
+
+static inline void config_section_unlock(struct section *co) {
+ netdata_mutex_unlock(&co->mutex);
+}
+
+
+// ----------------------------------------------------------------------------
+// config name-value index
+
+static int appconfig_option_compare(void *a, void *b) {
+ if(((struct config_option *)a)->hash < ((struct config_option *)b)->hash) return -1;
+ else if(((struct config_option *)a)->hash > ((struct config_option *)b)->hash) return 1;
+ else return strcmp(((struct config_option *)a)->name, ((struct config_option *)b)->name);
+}
+
+#define appconfig_option_index_add(co, cv) (struct config_option *)avl_insert_lock(&((co)->values_index), (avl *)(cv))
+#define appconfig_option_index_del(co, cv) (struct config_option *)avl_remove_lock(&((co)->values_index), (avl *)(cv))
+
+static struct config_option *appconfig_option_index_find(struct section *co, const char *name, uint32_t hash) {
+ struct config_option tmp;
+ tmp.hash = (hash)?hash:simple_hash(name);
+ tmp.name = (char *)name;
+
+ return (struct config_option *)avl_search_lock(&(co->values_index), (avl *) &tmp);
+}
+
+
+// ----------------------------------------------------------------------------
+// config sections index
+
+int appconfig_section_compare(void *a, void *b) {
+ if(((struct section *)a)->hash < ((struct section *)b)->hash) return -1;
+ else if(((struct section *)a)->hash > ((struct section *)b)->hash) return 1;
+ else return strcmp(((struct section *)a)->name, ((struct section *)b)->name);
+}
+
+#define appconfig_index_add(root, cfg) (struct section *)avl_insert_lock(&(root)->index, (avl *)(cfg))
+#define appconfig_index_del(root, cfg) (struct section *)avl_remove_lock(&(root)->index, (avl *)(cfg))
+
+static struct section *appconfig_index_find(struct config *root, const char *name, uint32_t hash) {
+ struct section tmp;
+ tmp.hash = (hash)?hash:simple_hash(name);
+ tmp.name = (char *)name;
+
+ return (struct section *)avl_search_lock(&root->index, (avl *) &tmp);
+}
+
+
+// ----------------------------------------------------------------------------
+// config section methods
+
+static inline struct section *appconfig_section_find(struct config *root, const char *section) {
+ return appconfig_index_find(root, section, 0);
+}
+
+static inline struct section *appconfig_section_create(struct config *root, const char *section) {
+ debug(D_CONFIG, "Creating section '%s'.", section);
+
+ struct section *co = callocz(1, sizeof(struct section));
+ co->name = strdupz(section);
+ co->hash = simple_hash(co->name);
+ netdata_mutex_init(&co->mutex);
+
+ avl_init_lock(&co->values_index, appconfig_option_compare);
+
+ if(unlikely(appconfig_index_add(root, co) != co))
+ error("INTERNAL ERROR: indexing of section '%s', already exists.", co->name);
+
+ appconfig_wrlock(root);
+ struct section *co2 = root->sections;
+ if(co2) {
+ while (co2->next) co2 = co2->next;
+ co2->next = co;
+ }
+ else root->sections = co;
+ appconfig_unlock(root);
+
+ return co;
+}
+
+
+// ----------------------------------------------------------------------------
+// config name-value methods
+
+static inline struct config_option *appconfig_value_create(struct section *co, const char *name, const char *value) {
+ debug(D_CONFIG, "Creating config entry for name '%s', value '%s', in section '%s'.", name, value, co->name);
+
+ struct config_option *cv = callocz(1, sizeof(struct config_option));
+ cv->name = strdupz(name);
+ cv->hash = simple_hash(cv->name);
+ cv->value = strdupz(value);
+
+ struct config_option *found = appconfig_option_index_add(co, cv);
+ if(found != cv) {
+ error("indexing of config '%s' in section '%s': already exists - using the existing one.", cv->name, co->name);
+ freez(cv->value);
+ freez(cv->name);
+ freez(cv);
+ return found;
+ }
+
+ config_section_wrlock(co);
+ struct config_option *cv2 = co->values;
+ if(cv2) {
+ while (cv2->next) cv2 = cv2->next;
+ cv2->next = cv;
+ }
+ else co->values = cv;
+ config_section_unlock(co);
+
+ return cv;
+}
+
+int appconfig_exists(struct config *root, const char *section, const char *name) {
+ struct config_option *cv;
+
+ debug(D_CONFIG, "request to get config in section '%s', name '%s'", section, name);
+
+ struct section *co = appconfig_section_find(root, section);
+ if(!co) return 0;
+
+ cv = appconfig_option_index_find(co, name, 0);
+ if(!cv) return 0;
+
+ return 1;
+}
+
+int appconfig_move(struct config *root, const char *section_old, const char *name_old, const char *section_new, const char *name_new) {
+ struct config_option *cv_old, *cv_new;
+ int ret = -1;
+
+ debug(D_CONFIG, "request to rename config in section '%s', old name '%s', to section '%s', new name '%s'", section_old, name_old, section_new, name_new);
+
+ struct section *co_old = appconfig_section_find(root, section_old);
+ if(!co_old) return ret;
+
+ struct section *co_new = appconfig_section_find(root, section_new);
+ if(!co_new) co_new = appconfig_section_create(root, section_new);
+
+ config_section_wrlock(co_old);
+ if(co_old != co_new)
+ config_section_wrlock(co_new);
+
+ cv_old = appconfig_option_index_find(co_old, name_old, 0);
+ if(!cv_old) goto cleanup;
+
+ cv_new = appconfig_option_index_find(co_new, name_new, 0);
+ if(cv_new) goto cleanup;
+
+ if(unlikely(appconfig_option_index_del(co_old, cv_old) != cv_old))
+ error("INTERNAL ERROR: deletion of config '%s' from section '%s', deleted tge wrong config entry.", cv_old->name, co_old->name);
+
+ if(co_old->values == cv_old) {
+ co_old->values = cv_old->next;
+ }
+ else {
+ struct config_option *t;
+ for(t = co_old->values; t && t->next != cv_old ;t = t->next) ;
+ if(!t || t->next != cv_old)
+ error("INTERNAL ERROR: cannot find variable '%s' in section '%s' of the config - but it should be there.", cv_old->name, co_old->name);
+ else
+ t->next = cv_old->next;
+ }
+
+ freez(cv_old->name);
+ cv_old->name = strdupz(name_new);
+ cv_old->hash = simple_hash(cv_old->name);
+
+ cv_new = cv_old;
+ cv_new->next = co_new->values;
+ co_new->values = cv_new;
+
+ if(unlikely(appconfig_option_index_add(co_new, cv_old) != cv_old))
+ error("INTERNAL ERROR: re-indexing of config '%s' in section '%s', already exists.", cv_old->name, co_new->name);
+
+ ret = 0;
+
+cleanup:
+ if(co_old != co_new)
+ config_section_unlock(co_new);
+ config_section_unlock(co_old);
+ return ret;
+}
+
+char *appconfig_get(struct config *root, const char *section, const char *name, const char *default_value)
+{
+ struct config_option *cv;
+
+ debug(D_CONFIG, "request to get config in section '%s', name '%s', default_value '%s'", section, name, default_value);
+
+ struct section *co = appconfig_section_find(root, section);
+ if(!co) co = appconfig_section_create(root, section);
+
+ cv = appconfig_option_index_find(co, name, 0);
+ if(!cv) {
+ cv = appconfig_value_create(co, name, default_value);
+ if(!cv) return NULL;
+ }
+ cv->flags |= CONFIG_VALUE_USED;
+
+ if((cv->flags & CONFIG_VALUE_LOADED) || (cv->flags & CONFIG_VALUE_CHANGED)) {
+ // this is a loaded value from the config file
+ // if it is different that the default, mark it
+ if(!(cv->flags & CONFIG_VALUE_CHECKED)) {
+ if(strcmp(cv->value, default_value) != 0) cv->flags |= CONFIG_VALUE_CHANGED;
+ cv->flags |= CONFIG_VALUE_CHECKED;
+ }
+ }
+
+ return(cv->value);
+}
+
+long long appconfig_get_number(struct config *root, const char *section, const char *name, long long value)
+{
+ char buffer[100], *s;
+ sprintf(buffer, "%lld", value);
+
+ s = appconfig_get(root, section, name, buffer);
+ if(!s) return value;
+
+ return strtoll(s, NULL, 0);
+}
+
+LONG_DOUBLE appconfig_get_float(struct config *root, const char *section, const char *name, LONG_DOUBLE value)
+{
+ char buffer[100], *s;
+ sprintf(buffer, "%0.5" LONG_DOUBLE_MODIFIER, value);
+
+ s = appconfig_get(root, section, name, buffer);
+ if(!s) return value;
+
+ return str2ld(s, NULL);
+}
+
+int appconfig_get_boolean(struct config *root, const char *section, const char *name, int value)
+{
+ char *s;
+ if(value) s = "yes";
+ else s = "no";
+
+ s = appconfig_get(root, section, name, s);
+ if(!s) return value;
+
+ if(!strcasecmp(s, "yes") || !strcasecmp(s, "true") || !strcasecmp(s, "on") || !strcasecmp(s, "auto") || !strcasecmp(s, "on demand")) return 1;
+ return 0;
+}
+
+int appconfig_get_boolean_ondemand(struct config *root, const char *section, const char *name, int value)
+{
+ char *s;
+
+ if(value == CONFIG_BOOLEAN_AUTO)
+ s = "auto";
+
+ else if(value == CONFIG_BOOLEAN_NO)
+ s = "no";
+
+ else
+ s = "yes";
+
+ s = appconfig_get(root, section, name, s);
+ if(!s) return value;
+
+ if(!strcmp(s, "yes"))
+ return CONFIG_BOOLEAN_YES;
+ else if(!strcmp(s, "no"))
+ return CONFIG_BOOLEAN_NO;
+ else if(!strcmp(s, "auto") || !strcmp(s, "on demand"))
+ return CONFIG_BOOLEAN_AUTO;
+
+ return value;
+}
+
+const char *appconfig_set_default(struct config *root, const char *section, const char *name, const char *value)
+{
+ struct config_option *cv;
+
+ debug(D_CONFIG, "request to set default config in section '%s', name '%s', value '%s'", section, name, value);
+
+ struct section *co = appconfig_section_find(root, section);
+ if(!co) return appconfig_set(root, section, name, value);
+
+ cv = appconfig_option_index_find(co, name, 0);
+ if(!cv) return appconfig_set(root, section, name, value);
+
+ cv->flags |= CONFIG_VALUE_USED;
+
+ if(cv->flags & CONFIG_VALUE_LOADED)
+ return cv->value;
+
+ if(strcmp(cv->value, value) != 0) {
+ cv->flags |= CONFIG_VALUE_CHANGED;
+
+ freez(cv->value);
+ cv->value = strdupz(value);
+ }
+
+ return cv->value;
+}
+
+const char *appconfig_set(struct config *root, const char *section, const char *name, const char *value)
+{
+ struct config_option *cv;
+
+ debug(D_CONFIG, "request to set config in section '%s', name '%s', value '%s'", section, name, value);
+
+ struct section *co = appconfig_section_find(root, section);
+ if(!co) co = appconfig_section_create(root, section);
+
+ cv = appconfig_option_index_find(co, name, 0);
+ if(!cv) cv = appconfig_value_create(co, name, value);
+ cv->flags |= CONFIG_VALUE_USED;
+
+ if(strcmp(cv->value, value) != 0) {
+ cv->flags |= CONFIG_VALUE_CHANGED;
+
+ freez(cv->value);
+ cv->value = strdupz(value);
+ }
+
+ return value;
+}
+
+long long appconfig_set_number(struct config *root, const char *section, const char *name, long long value)
+{
+ char buffer[100];
+ sprintf(buffer, "%lld", value);
+
+ appconfig_set(root, section, name, buffer);
+
+ return value;
+}
+
+LONG_DOUBLE appconfig_set_float(struct config *root, const char *section, const char *name, LONG_DOUBLE value)
+{
+ char buffer[100];
+ sprintf(buffer, "%0.5" LONG_DOUBLE_MODIFIER, value);
+
+ appconfig_set(root, section, name, buffer);
+
+ return value;
+}
+
+int appconfig_set_boolean(struct config *root, const char *section, const char *name, int value)
+{
+ char *s;
+ if(value) s = "yes";
+ else s = "no";
+
+ appconfig_set(root, section, name, s);
+
+ return value;
+}
+
+
+// ----------------------------------------------------------------------------
+// config load/save
+
+int appconfig_load(struct config *root, char *filename, int overwrite_used)
+{
+ int line = 0;
+ struct section *co = NULL;
+
+ char buffer[CONFIG_FILE_LINE_MAX + 1], *s;
+
+ if(!filename) filename = CONFIG_DIR "/" CONFIG_FILENAME;
+
+ debug(D_CONFIG, "CONFIG: opening config file '%s'", filename);
+
+ FILE *fp = fopen(filename, "r");
+ if(!fp) {
+ // info("CONFIG: cannot open file '%s'. Using internal defaults.", filename);
+ return 0;
+ }
+
+ while(fgets(buffer, CONFIG_FILE_LINE_MAX, fp) != NULL) {
+ buffer[CONFIG_FILE_LINE_MAX] = '\0';
+ line++;
+
+ s = trim(buffer);
+ if(!s || *s == '#') {
+ debug(D_CONFIG, "CONFIG: ignoring line %d of file '%s', it is empty.", line, filename);
+ continue;
+ }
+
+ int len = (int) strlen(s);
+ if(*s == '[' && s[len - 1] == ']') {
+ // new section
+ s[len - 1] = '\0';
+ s++;
+
+ co = appconfig_section_find(root, s);
+ if(!co) co = appconfig_section_create(root, s);
+
+ continue;
+ }
+
+ if(!co) {
+ // line outside a section
+ error("CONFIG: ignoring line %d ('%s') of file '%s', it is outside all sections.", line, s, filename);
+ continue;
+ }
+
+ char *name = s;
+ char *value = strchr(s, '=');
+ if(!value) {
+ error("CONFIG: ignoring line %d ('%s') of file '%s', there is no = in it.", line, s, filename);
+ continue;
+ }
+ *value = '\0';
+ value++;
+
+ name = trim(name);
+ value = trim(value);
+
+ if(!name || *name == '#') {
+ error("CONFIG: ignoring line %d of file '%s', name is empty.", line, filename);
+ continue;
+ }
+
+ if(!value) value = "";
+
+ struct config_option *cv = appconfig_option_index_find(co, name, 0);
+
+ if(!cv) cv = appconfig_value_create(co, name, value);
+ else {
+ if(((cv->flags & CONFIG_VALUE_USED) && overwrite_used) || !(cv->flags & CONFIG_VALUE_USED)) {
+ debug(D_CONFIG, "CONFIG: line %d of file '%s', overwriting '%s/%s'.", line, filename, co->name, cv->name);
+ freez(cv->value);
+ cv->value = strdupz(value);
+ }
+ else
+ debug(D_CONFIG, "CONFIG: ignoring line %d of file '%s', '%s/%s' is already present and used.", line, filename, co->name, cv->name);
+ }
+ cv->flags |= CONFIG_VALUE_LOADED;
+ }
+
+ fclose(fp);
+
+ return 1;
+}
+
+void appconfig_generate(struct config *root, BUFFER *wb, int only_changed)
+{
+ int i, pri;
+ struct section *co;
+ struct config_option *cv;
+
+ for(i = 0; i < 3 ;i++) {
+ switch(i) {
+ case 0:
+ buffer_strcat(wb,
+ "# netdata configuration\n"
+ "#\n"
+ "# You can download the latest version of this file, using:\n"
+ "#\n"
+ "# wget -O /etc/netdata/netdata.conf http://localhost:19999/netdata.conf\n"
+ "# or\n"
+ "# curl -o /etc/netdata/netdata.conf http://localhost:19999/netdata.conf\n"
+ "#\n"
+ "# You can uncomment and change any of the options below.\n"
+ "# The value shown in the commented settings, is the default value.\n"
+ "#\n"
+ "\n# global netdata configuration\n");
+ break;
+
+ case 1:
+ buffer_strcat(wb, "\n\n# per plugin configuration\n");
+ break;
+
+ case 2:
+ buffer_strcat(wb, "\n\n# per chart configuration\n");
+ break;
+ }
+
+ appconfig_wrlock(root);
+ for(co = root->sections; co ; co = co->next) {
+ if(!strcmp(co->name, CONFIG_SECTION_GLOBAL)
+ || !strcmp(co->name, CONFIG_SECTION_WEB)
+ || !strcmp(co->name, CONFIG_SECTION_STATSD)
+ || !strcmp(co->name, CONFIG_SECTION_PLUGINS)
+ || !strcmp(co->name, CONFIG_SECTION_CLOUD)
+ || !strcmp(co->name, CONFIG_SECTION_REGISTRY)
+ || !strcmp(co->name, CONFIG_SECTION_HEALTH)
+ || !strcmp(co->name, CONFIG_SECTION_BACKEND)
+ || !strcmp(co->name, CONFIG_SECTION_STREAM)
+ )
+ pri = 0;
+ else if(!strncmp(co->name, "plugin:", 7)) pri = 1;
+ else pri = 2;
+
+ if(i == pri) {
+ int loaded = 0;
+ int used = 0;
+ int changed = 0;
+ int count = 0;
+
+ config_section_wrlock(co);
+ for(cv = co->values; cv ; cv = cv->next) {
+ used += (cv->flags & CONFIG_VALUE_USED)?1:0;
+ loaded += (cv->flags & CONFIG_VALUE_LOADED)?1:0;
+ changed += (cv->flags & CONFIG_VALUE_CHANGED)?1:0;
+ count++;
+ }
+ config_section_unlock(co);
+
+ if(!count) continue;
+ if(only_changed && !changed && !loaded) continue;
+
+ if(!used) {
+ buffer_sprintf(wb, "\n# section '%s' is not used.", co->name);
+ }
+
+ buffer_sprintf(wb, "\n[%s]\n", co->name);
+
+ config_section_wrlock(co);
+ for(cv = co->values; cv ; cv = cv->next) {
+
+ if(used && !(cv->flags & CONFIG_VALUE_USED)) {
+ buffer_sprintf(wb, "\n\t# option '%s' is not used.\n", cv->name);
+ }
+ buffer_sprintf(wb, "\t%s%s = %s\n", ((!(cv->flags & CONFIG_VALUE_LOADED)) && (!(cv->flags & CONFIG_VALUE_CHANGED)) && (cv->flags & CONFIG_VALUE_USED))?"# ":"", cv->name, cv->value);
+ }
+ config_section_unlock(co);
+ }
+ }
+ appconfig_unlock(root);
+ }
+}
diff --git a/libnetdata/config/appconfig.h b/libnetdata/config/appconfig.h
new file mode 100644
index 0000000..78099aa
--- /dev/null
+++ b/libnetdata/config/appconfig.h
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+/*
+ * This section manages ini config files, like netdata.conf and stream.conf
+ *
+ * It is organized like this:
+ *
+ * struct config (i.e. netdata.conf or stream.conf)
+ * .sections = a linked list of struct section
+ * .mutex = a mutex to protect the above linked list due to multi-threading
+ * .index = an AVL tree of struct section
+ *
+ * struct section (i.e. [global] or [health] of netdata.conf)
+ * .value = a linked list of struct config_option
+ * .mutex = a mutex to protect the above linked list due to multi-threading
+ * .value_index = an AVL tree of struct config_option
+ *
+ * struct config_option (ie. a name-value pair for each ini file option)
+ *
+ * The following operations on name-value options are supported:
+ * SET to set the value of an option
+ * SET DEFAULT to set the value and the default value of an option
+ * GET to get the value of an option
+ * EXISTS to check if an option exists
+ * MOVE to move an option from a section to another section, and/or rename it
+ *
+ * GET and SET operations are provided for the following data types:
+ * STRING
+ * NUMBER (long long)
+ * FLOAT (long double)
+ * BOOLEAN (false, true)
+ * BOOLEAN ONDEMAND (false, true, auto)
+ *
+ * GET and SET operations create struct config_option, if it is not already present.
+ * This allows netdata to run even without netdata.conf and stream.conf. The internal
+ * defaults are used to create the structure that should exist in the ini file and the config
+ * file can be downloaded from the server.
+ *
+ * Also 2 operations are supported for the whole config file:
+ *
+ * LOAD To load the ini file from disk
+ * GENERATE To generate the ini file (this is used to download the ini file from the server)
+ *
+ * For each option (name-value pair), the system maintains 4 flags:
+ * LOADED to indicate that the value has been loaded from the file
+ * USED to indicate that netdata used the value
+ * CHANGED to indicate that the value has been changed from the loaded value or the internal default value
+ * CHECKED is used internally for optimization (to avoid an strcmp() every time GET is called).
+ *
+ * TODO:
+ * 1. The linked lists and the mutexes can be removed and the AVL trees can become DICTIONARY.
+ * This part of the code was written before we add traversal to AVL.
+ *
+ * 2. High level data types could be supported, to simplify the rest of the code:
+ * MULTIPLE CHOICE to let the user select one of the supported keywords
+ * this would allow users see in comments the available options
+ *
+ * SIMPLE PATTERN to let the user define netdata SIMPLE PATTERNS
+ *
+ * 3. Sorting of options should be supported.
+ * Today, when the ini file is downloaded from the server, the options are shown in the order
+ * they appear in the linked list (the order they were added, listing changed options first).
+ * If we remove the linked list, the order they appear in the AVL tree will be used (which is
+ * random due to simple_hash()).
+ * Ideally, we support sorting of options when generating the ini file.
+ *
+ * 4. There is no free() operation. So, memory is freed on netdata exit.
+ *
+ * 5. Avoid memory fragmentation
+ * Since entries are created from multiple threads and a lot of allocations are required
+ * for each config_option, fragmentation can be a problem for IoT.
+ *
+ * 6. Although this way of managing options is quite flexible and dynamic, it wastes memory
+ * for the names of the options. Since most of the option names are static, we could provide
+ * a method to allocate only the dynamic option names.
+ */
+
+#ifndef NETDATA_CONFIG_H
+#define NETDATA_CONFIG_H 1
+
+#include "../libnetdata.h"
+
+#define CONFIG_FILENAME "netdata.conf"
+
+#define CONFIG_SECTION_GLOBAL "global"
+#define CONFIG_SECTION_WEB "web"
+#define CONFIG_SECTION_STATSD "statsd"
+#define CONFIG_SECTION_PLUGINS "plugins"
+#define CONFIG_SECTION_CLOUD "cloud"
+#define CONFIG_SECTION_REGISTRY "registry"
+#define CONFIG_SECTION_HEALTH "health"
+#define CONFIG_SECTION_BACKEND "backend"
+#define CONFIG_SECTION_STREAM "stream"
+
+// these are used to limit the configuration names and values lengths
+// they are not enforced by config.c functions (they will strdup() all strings, no matter of their length)
+#define CONFIG_MAX_NAME 1024
+#define CONFIG_MAX_VALUE 2048
+
+struct config {
+ struct section *sections;
+ netdata_mutex_t mutex;
+ avl_tree_lock index;
+};
+
+#define CONFIG_BOOLEAN_INVALID 100 // an invalid value to check for validity (used as default initialization when needed)
+
+#define CONFIG_BOOLEAN_NO 0 // disabled
+#define CONFIG_BOOLEAN_YES 1 // enabled
+
+#ifndef CONFIG_BOOLEAN_AUTO
+#define CONFIG_BOOLEAN_AUTO 2 // enabled if it has useful info when enabled
+#endif
+
+extern int appconfig_load(struct config *root, char *filename, int overwrite_used);
+
+extern char *appconfig_get(struct config *root, const char *section, const char *name, const char *default_value);
+extern long long appconfig_get_number(struct config *root, const char *section, const char *name, long long value);
+extern LONG_DOUBLE appconfig_get_float(struct config *root, const char *section, const char *name, LONG_DOUBLE value);
+extern int appconfig_get_boolean(struct config *root, const char *section, const char *name, int value);
+extern int appconfig_get_boolean_ondemand(struct config *root, const char *section, const char *name, int value);
+
+extern const char *appconfig_set(struct config *root, const char *section, const char *name, const char *value);
+extern const char *appconfig_set_default(struct config *root, const char *section, const char *name, const char *value);
+extern long long appconfig_set_number(struct config *root, const char *section, const char *name, long long value);
+extern LONG_DOUBLE appconfig_set_float(struct config *root, const char *section, const char *name, LONG_DOUBLE value);
+extern int appconfig_set_boolean(struct config *root, const char *section, const char *name, int value);
+
+extern int appconfig_exists(struct config *root, const char *section, const char *name);
+extern int appconfig_move(struct config *root, const char *section_old, const char *name_old, const char *section_new, const char *name_new);
+
+extern void appconfig_generate(struct config *root, BUFFER *wb, int only_changed);
+
+extern int appconfig_section_compare(void *a, void *b);
+
+#endif /* NETDATA_CONFIG_H */