Use CreateTimeSeries to write agent metrics (#154)

* Use CreateTimeSeries to write agent metrics.

This replaces CreateCollectdTimeSeries only for the metrics that the Stackdriver Monitoring plugin reports about itself.

src/stackdriver_agent.c

@@ -28,6 +28,8 @@
 #include "liboconfig/oconfig.h"
 #include "stackdriver-agent-keys.h"
 
+#define AGENT_PREFIX "agent.googleapis.com/agent"
+
 static const char this_plugin_name[] = "stackdriver_agent";
 
 static const char *hostname = NULL;
@@ -119,10 +121,17 @@ static int sagt_read(user_data_t *user_data)
  value_list_t vl = {}; // zero-init
  sstrncpy(vl.plugin, this_plugin_name, sizeof(vl.plugin));
 
+ // This function passes metric information using two mechanisms. The standard
+ // collectd type and type_instance are useful for most plugins and expected by
+ // some of the caching inside collectd, and the Stackdriver metadata is needed
+ // to write these with the CreateTimeSeries call in the write_gcm plug-in.
+
  // uptime
  {
  meta_data_t *md = meta_data_create();
- if (meta_data_add_string(md, "version", COLLECTD_USERAGENT) == 0) {
+ if (meta_data_add_string(
+ md, "stackdriver_metric_type", AGENT_PREFIX "/uptime") == 0 &&
+ meta_data_add_string(md, "label:version", COLLECTD_USERAGENT) == 0) {
  derive_t uptime = CDTIME_T_TO_TIME_T(now - ctx->start_time);
  sagt_submit_derive("uptime", NULL, now, interval, uptime, md);
  }
@@ -135,9 +144,15 @@ static int sagt_read(user_data_t *user_data)
  if (f) {
  size_t vm = 0;
  if (fscanf(f, "%zu", &vm)) {
+ meta_data_t *md = meta_data_create();
  long page_size = sysconf(_SC_PAGESIZE);
  size_t mused = vm * page_size;
- sagt_submit_gauge("memory_usage", NULL, now, interval, mused, NULL);
+ if (meta_data_add_string(
+ md, "stackdriver_metric_type",
+ AGENT_PREFIX "/memory_usage") == 0) {
+ sagt_submit_gauge("memory_usage", NULL, now, interval, mused, md);
+ }
+ meta_data_destroy(md);
  }
  fclose(f);
  }
@@ -146,39 +161,58 @@ static int sagt_read(user_data_t *user_data)
  // Stats for API requests. The corresponding uc_meta_data_set calls are in
  // write_gcm.c.
  {
- uint64_t value;
- if (uc_meta_data_get_unsigned_int(
- &vl, SAGT_API_REQUESTS_SUCCESS, &value) == 0) {
- sagt_submit_derive("api_request_count", "success",
- now, interval, value, NULL);
- }
- if (uc_meta_data_get_unsigned_int(
- &vl, SAGT_API_REQUESTS_CONNECTIVITY_FAILURES, &value) == 0) {
- sagt_submit_derive("api_request_count", "connectivity_failures",
- now, interval, value, NULL);
- }
- if (uc_meta_data_get_unsigned_int(
- &vl, SAGT_API_REQUESTS_ERRORS, &value) == 0) {
- sagt_submit_derive("api_request_count", "errors",
- now, interval, value, NULL);
+ meta_data_t *md = meta_data_create();
+ if (meta_data_add_string(
+ md, "stackdriver_metric_type",
+ AGENT_PREFIX "/api_request_count") == 0) {
+ uint64_t value;
+ if (uc_meta_data_get_unsigned_int(
+ &vl, SAGT_API_REQUESTS_SUCCESS, &value) == 0 &&
+ meta_data_add_string(md, "label:state", "success") == 0) {
+ sagt_submit_derive(
+ "api_request_count", "success", now, interval, value, md);
+ }
+ if (uc_meta_data_get_unsigned_int(
+ &vl, SAGT_API_REQUESTS_CONNECTIVITY_FAILURES, &value) == 0 &&
+ meta_data_add_string(
+ md, "label:state", "connectivity_failures") == 0) {
+ sagt_submit_derive(
+ "api_request_count", "connectivity_failures", now, interval, value,
+ md);
+ }
+ if (uc_meta_data_get_unsigned_int(
+ &vl, SAGT_API_REQUESTS_ERRORS, &value) == 0 &&
+ meta_data_add_string(md, "label:state", "errors") == 0) {
+ sagt_submit_derive(
+ "api_request_count", "errors", now, interval, value, md);
+ }
  }
+ meta_data_destroy(md);
  }
 
  // Cloud Monarch-related stats. The corresponding uc_meta_data_set calls are in
  // match_throttle_metadata_keys.c.
  {
+ meta_data_t *md = meta_data_create();
  uint64_t streamspace_size;
  _Bool throttling;
- if (uc_meta_data_get_unsigned_int(
+ if (meta_data_add_string(
+ md, "stackdriver_metric_type",
+ AGENT_PREFIX "/streamspace_size") == 0 &&
+ uc_meta_data_get_unsigned_int(
  &vl, SAGT_STREAMSPACE_SIZE, &streamspace_size) == 0) {
- sagt_submit_gauge("streamspace_size", NULL,
-  now, interval, streamspace_size, NULL);
+ sagt_submit_gauge(
+ "streamspace_size", NULL, now, interval, streamspace_size, md);
  }
- if (uc_meta_data_get_boolean(
+ if (meta_data_add_string(
+ md, "stackdriver_metric_type",
+ AGENT_PREFIX "/streamspace_size_throttling") == 0 &&
+ uc_meta_data_get_boolean(
  &vl, SAGT_STREAMSPACE_SIZE_THROTTLING, &throttling) == 0) {
- sagt_submit_gauge("streamspace_size_throttling", NULL,
-  now, interval, throttling, NULL);
+ sagt_submit_gauge(
+ "streamspace_size_throttling", NULL, now, interval, throttling, md);
  }
+ meta_data_destroy(md);
  }
 
  return 0;