Allow netdata plugins to expose functions for querying more information about specific charts (#13720)

* function renames and code cleanup in popen.c; no actual code changes

* netdata popen() now opens both child process stdin and stdout and returns FILE * for both

* pass both input and output to parser structures

* updated rrdset to call custom functions

* RRDSET FUNCTION leading calls for both sync and async operation

* put RRDSET functions to a separate file

* added format and timeout at function definition

* support for synchronous (internal plugins) and asynchronous (external plugins and children) functions

* /api/v1/function endpoint

* functions are now attached to the host and there is a dictionary view per chart

* functions implemented at plugins.d

* remove the defer until keyword hook from plugins.d when it is done

* stream sender implementation of functions

* sanitization of all functions so that certain characters are only allowed

* strictier sanitization

* common max size

* 1st working plugins.d example

* always init inflight dictionary

* properly destroy dictionaries to avoid parallel insertion of items

* add more debugging on disconnection reasons

* add more debugging on disconnection reasons again

* streaming receiver respects newlines

* dont use the same fp for both streaming receive and send

* dont free dbengine memory with internal checks

* make sender proceed in the buffer

* added timing info and garbage collection at plugins.d

* added info about routing nodes

* added info about routing nodes with delay

* added more info about delays

* added more info about delays again

* signal sending thread to wake up

* streaming version labeling and commented code to support capabilities

* added functions to /api/v1/data, /api/v1/charts, /api/v1/chart, /api/v1/info

* redirect top output to stdout

* address coverity findings

* fix resource leaks of popen

* log attempts to connect to individual destinations

* better messages

* properly parse destinations

* try to find a function from the most matching to the least matching

* log added streaming destinations

* rotate destinations bypassing a node in the middle that does not accept our connection

* break the loops properly

* use typedef to define callbacks

* capabilities negotiation during streaming

* functions exposed upstream based on capabilities; compression disabled per node persisting reconnects; always try to connect with all capabilities

* restore functionality to lookup functions

* better logging of capabilities

* remove old versions from capabilities when a newer version is there

* fix formatting

* optimization for plugins.d rrdlabels to avoid creating and destructing dictionaries all the time

* delayed health initialization for rrddim and rrdset

* cleanup health initialization

* fix for popen() not returning the right value

* add health worker jobs for initializing rrdset and rrddim

* added content type support for functions; apps.plugin permanent function to display all the processes

* fixes for functions parameters parsing in apps.plugin

* fix for process matching in apps.plugiin

* first working function for apps.plugin

* Dashboard ACL is disabled for functions; Function errors are all in JSON format

* apps.plugin function processes returns json table

* use json_escape_string() to escape message

* fix formatting

* apps.plugin exposes all its metrics to function processes

* fix json formatting when filtering out some rows

* reopen the internal pipe of rrdpush in case of errors

* misplaced statement

* do not use buffer->len

* support for GLOBAL functions (functions that are not linked to a chart

* added /api/v1/functions endpoint; removed format from the FUNCTIONS api;

* swagger documentation about the new api end points

* added plugins.d documentation about functions

* never re-close a file

* remove uncessesary ifdef

* fixed issues identified by codacy

* fix for null label value

* make edit-config copy-and-paste friendly

* Revert "make edit-config copy-and-paste friendly"

This reverts commit 54500c0e0a97f65a0c66c4d34e966f6a9056698e.

* reworked sender handshake to fix coverity findings

* timeout is zero, for both send_timeout() and recv_timeout()

* properly detect that parent closed the socket

* support caching of function responses; limit function response to 10MB; added protection from malformed function responses

* disabled excessive logging

* added units to apps.plugin function processes and normalized all values to be human readable

* shorter field names

* fixed issues reported

* fixed apps.plugin error response; tested that pluginsd can properly handle faulty responses

* use double linked list macros for double linked list management

* faster apps.plugin function printing by minimizing file operations

* added memory percentage

* fix compatibility issues with older compilers and FreeBSD

* rrdpush sender code cleanup; rrhost structure cleanup from sender flags and variables;

* fix letftover variable in ifdef

* apps.plugin: do not call detach from the thread; exit immediately when input is broken

* exclude AR charts from health

* flush cleaner; prefer sender output

* clarity

* do not fill the cbuffer if not connected

* fix

* dont enabled host->sender if streaming is not enabled; send host label updates to parent;

* functions are only available through ACLK

* Prepared statement reports only in dev mode

* fix AR chart detection

* fix for streaming not being enabling itself

* more cleanup of sender and receiver structures

* moved read-only flags and configuration options to rrdhost->options

* fixed merge with master

* fix for incomplete rename

* prevent service thread from working on charts that are being collected

Co-authored-by: Stelios Fragkakis <52996999+stelfrag@users.noreply.github.com>

1 files changed, 26 insertions, 24 deletions

diff --git a/collectors/cgroups.plugin/sys_fs_cgroup.c b/collectors/cgroups.plugin/sys_fs_cgroup.c
index 74aedf2b52..3bee46dcf4 100644
--- a/collectors/cgroups.plugin/sys_fs_cgroup.c
+++ b/collectors/cgroups.plugin/sys_fs_cgroup.c
@@ -153,14 +153,15 @@ static enum cgroups_systemd_setting cgroups_detect_systemd(const char *exec)
     char buf[MAXSIZE_PROC_CMDLINE];
     char *begin, *end;
 
-    FILE *f = mypopen(exec, &command_pid);
+    FILE *fp_child_input;
+    FILE *fp_child_output = netdata_popen(exec, &command_pid, &fp_child_input);
 
-    if (!f)
+    if (!fp_child_output)
         return retval;
 
     fd_set rfds;
     struct timeval timeout;
-    int fd = fileno(f);
+    int fd = fileno(fp_child_output);
     int ret = -1;
 
     FD_ZERO(&rfds);
@@ -177,7 +178,7 @@ static enum cgroups_systemd_setting cgroups_detect_systemd(const char *exec)
     } else if (ret == 0) {
         info("Cannot get the output of \"%s\" within %"PRId64" seconds", exec, (int64_t)timeout.tv_sec);
     } else {
-        while (fgets(buf, MAXSIZE_PROC_CMDLINE, f) != NULL) {
+        while (fgets(buf, MAXSIZE_PROC_CMDLINE, fp_child_output) != NULL) {
             if ((begin = strstr(buf, SYSTEMD_HIERARCHY_STRING))) {
                 end = begin = begin + strlen(SYSTEMD_HIERARCHY_STRING);
                 if (!*begin)
@@ -196,7 +197,7 @@ static enum cgroups_systemd_setting cgroups_detect_systemd(const char *exec)
         }
     }
 
-    if (mypclose(f, command_pid))
+    if (netdata_pclose(fp_child_input, fp_child_output, command_pid))
         return SYSTEMD_CGROUP_ERR;
 
     return retval;
@@ -210,18 +211,19 @@ static enum cgroups_type cgroups_try_detect_version()
     int cgroups2_available = 0;
 
     // 1. check if cgroups2 available on system at all
-    FILE *f = mypopen("grep cgroup /proc/filesystems", &command_pid);
-    if (!f) {
+    FILE *fp_child_input;
+    FILE *fp_child_output = netdata_popen("grep cgroup /proc/filesystems", &command_pid, &fp_child_input);
+    if (!fp_child_output) {
         error("popen failed");
         return CGROUPS_AUTODETECT_FAIL;
     }
-    while (fgets(buf, MAXSIZE_PROC_CMDLINE, f) != NULL) {
+    while (fgets(buf, MAXSIZE_PROC_CMDLINE, fp_child_output) != NULL) {
         if (strstr(buf, "cgroup2")) {
             cgroups2_available = 1;
             break;
         }
     }
-    if(mypclose(f, command_pid))
+    if(netdata_pclose(fp_child_input, fp_child_output, command_pid))
         return CGROUPS_AUTODETECT_FAIL;
 
     if(!cgroups2_available)
@@ -254,19 +256,19 @@ static enum cgroups_type cgroups_try_detect_version()
 
     // 4. if we are unified as on Fedora (default cgroups2 only mode)
     //    check kernel command line flag that can override that setting
-    f = fopen("/proc/cmdline", "r");
-    if (!f) {
+    FILE *fp = fopen("/proc/cmdline", "r");
+    if (!fp) {
         error("Error reading kernel boot commandline parameters");
         return CGROUPS_AUTODETECT_FAIL;
     }
 
-    if (!fgets(buf, MAXSIZE_PROC_CMDLINE, f)) {
+    if (!fgets(buf, MAXSIZE_PROC_CMDLINE, fp)) {
         error("couldn't read all cmdline params into buffer");
-        fclose(f);
+        fclose(fp);
         return CGROUPS_AUTODETECT_FAIL;
     }
 
-    fclose(f);
+    fclose(fp);
 
     if (strstr(buf, "systemd.unified_cgroup_hierarchy=0")) {
         info("cgroups v2 (unified cgroups) is available but are disabled on this system.");
@@ -1665,16 +1667,16 @@ static inline void read_cgroup_network_interfaces(struct cgroup *cg) {
     }
 
     debug(D_CGROUP, "executing cgroup_identifier %s --cgroup '%s' for cgroup '%s'", cgroups_network_interface_script, cgroup_identifier, cg->id);
-    FILE *fp;
-    (void)mypopen_raw_default_flags_and_environment(&cgroup_pid, &fp, cgroups_network_interface_script, "--cgroup", cgroup_identifier);
-    if(!fp) {
+    FILE *fp_child_input, *fp_child_output;
+    (void)netdata_popen_raw_default_flags_and_environment(&cgroup_pid, &fp_child_input, &fp_child_output, cgroups_network_interface_script, "--cgroup", cgroup_identifier);
+    if(!fp_child_output) {
         error("CGROUP: cannot popen(%s --cgroup \"%s\", \"r\").", cgroups_network_interface_script, cgroup_identifier);
         return;
     }
 
     char *s;
     char buffer[CGROUP_NETWORK_INTERFACE_MAX_LINE + 1];
-    while((s = fgets(buffer, CGROUP_NETWORK_INTERFACE_MAX_LINE, fp))) {
+    while((s = fgets(buffer, CGROUP_NETWORK_INTERFACE_MAX_LINE, fp_child_output))) {
         trim(s);
 
         if(*s && *s != '\n') {
@@ -1709,7 +1711,7 @@ static inline void read_cgroup_network_interfaces(struct cgroup *cg) {
         }
     }
 
-    mypclose(fp, cgroup_pid);
+    netdata_pclose(fp_child_input, fp_child_output, cgroup_pid);
     // debug(D_CGROUP, "closed cgroup_identifier for cgroup '%s'", cg->id);
 }
 
@@ -1871,9 +1873,9 @@ static inline void discovery_rename_cgroup(struct cgroup *cg) {
     debug(D_CGROUP, "executing command %s \"%s\" for cgroup '%s'", cgroups_rename_script, cg->intermediate_id, cg->chart_id);
     pid_t cgroup_pid;
 
-    FILE *fp;
-    (void)mypopen_raw_default_flags_and_environment(&cgroup_pid, &fp, cgroups_rename_script, cg->id, cg->intermediate_id);
-    if (!fp) {
+    FILE *fp_child_input, *fp_child_output;
+    (void)netdata_popen_raw_default_flags_and_environment(&cgroup_pid, &fp_child_input, &fp_child_output, cgroups_rename_script, cg->id, cg->intermediate_id);
+    if (!fp_child_output) {
         error("CGROUP: cannot popen(%s \"%s\", \"r\").", cgroups_rename_script, cg->intermediate_id);
         cg->pending_renames = 0;
         cg->processed = 1;
@@ -1881,8 +1883,8 @@ static inline void discovery_rename_cgroup(struct cgroup *cg) {
     }
 
     char buffer[CGROUP_CHARTID_LINE_MAX + 1];
-    char *new_name = fgets(buffer, CGROUP_CHARTID_LINE_MAX, fp);
-    int exit_code = mypclose(fp, cgroup_pid);
+    char *new_name = fgets(buffer, CGROUP_CHARTID_LINE_MAX, fp_child_output);
+    int exit_code = netdata_pclose(fp_child_input, fp_child_output, cgroup_pid);
 
     switch (exit_code) {
         case 0: