From 0c07b0faa4c5b9dd486e36ceada4401c1a24b487 Mon Sep 17 00:00:00 2001
From: Florian Forster <octo@collectd.org>
Date: Sat, 9 Dec 2017 07:37:35 +0100
Subject: [PATCH] write_stackdriver plugin: Use the "Label" option inside
 "Resource" blocks.

The previous implementation was too surprising for users, which is not a good
property for a config option.
---
 src/collectd.conf.in    |  2 +-
 src/collectd.conf.pod   | 40 +++++++++++++++++++++++++++-------------
 src/write_stackdriver.c | 21 +++++++++++----------
 3 files changed, 39 insertions(+), 24 deletions(-)

diff --git a/src/collectd.conf.in b/src/collectd.conf.in
index 184d0b93..94214759 100644
--- a/src/collectd.conf.in
+++ b/src/collectd.conf.in
@@ -1793,7 +1793,7 @@
 #  CredentialFile "/path/to/gcp-project-id-12345.json"
 #  Email "123456789012@developer.gserviceaccount.com"
 #  <Resource "global">
-#    project_id "gcp-project-id"
+#    Label "project_id" "gcp-project-id"
 #  </Resource>
 #  Url "https://monitoring.googleapis.com/v3"
 #</Plugin>
diff --git a/src/collectd.conf.pod b/src/collectd.conf.pod
index b73ab681..da8e8736 100644
--- a/src/collectd.conf.pod
+++ b/src/collectd.conf.pod
@@ -10323,7 +10323,7 @@ B<Synopsis:>
  <Plugin write_stackdriver>
    CredentialFile "/path/to/service_account.json"
    <Resource "global">
-     project_id "monitored_project"
+     Label "project_id" "monitored_project"
    </Resource>
  </Plugin>
 
@@ -10347,7 +10347,7 @@ credentials.
 
 =item
 
-The patch C<${HOME}/.config/gcloud/application_default_credentials.json> is
+The path C<${HOME}/.config/gcloud/application_default_credentials.json> is
 checked. This where credentials used by the I<gcloud> command line utility are
 stored. You can use C<gcloud auth application-default login> to create these
 credentials.
@@ -10388,30 +10388,44 @@ I<write_stackdriver plugin>.
 
 =item B<Resource> I<ResourceType>
 
-Configures the I<Monitored Resource> to use when storing metrics. This option
-takes a I<ResourceType> and arbitrary string options which are used as labels.
+Configures the I<Monitored Resource> to use when storing metrics.
+More information on I<Monitored Resources> and I<Monitored Resource Types> are
+available at L<https://cloud.google.com/monitoring/api/resources>.
 
-On GCE, defaults to the equivalent of this config:
+This block takes one string argument, the I<ResourceType>. Inside the block are
+one or more B<Label> options which configure the resource labels.
+
+This block is optional. The default value depends on the runtime environment:
+on GCE, the C<gce_instance> resource type is used, otherwise the C<global>
+resource type ist used:
+
+=over 4
+
+=item
+
+B<On GCE>, defaults to the equivalent of this config:
 
   <Resource "gce_instance">
-    project_id "<project_id>"
-    instance_id "<instance_id>"
-    zone "<zone>"
+    Label "project_id" "<project_id>"
+    Label "instance_id" "<instance_id>"
+    Label "zone" "<zone>"
   </Resource>
 
 The values for I<project_id>, I<instance_id> and I<zone> are read from the GCE
 metadata service.
 
-When not running on GCE, defaults to the equivalent of this config:
+=item
+
+B<Elsewhere>, i.e. not on GCE, defaults to the equivalent of this config:
 
   <Resource "global">
-    project_id "<Project>"
+    Label "project_id" "<Project>"
   </Resource>
 
-Where I<Project> refers to the value of the B<Project> option.
+Where I<Project> refers to the value of the B<Project> option or the project ID
+inferred from the B<CredentialFile>.
 
-See L<https://cloud.google.com/monitoring/api/resources> for more information
-on I<Monitored Resource Types>.
+=back
 
 =item B<Url> I<Url>
 
diff --git a/src/write_stackdriver.c b/src/write_stackdriver.c
index e6d3b74a..574191d4 100644
--- a/src/write_stackdriver.c
+++ b/src/write_stackdriver.c
@@ -486,17 +486,18 @@ static int wg_config_resource(oconfig_item_t *ci, wg_callback_t *cb) /* {{{ */
   for (int i = 0; i < ci->children_num; i++) {
     oconfig_item_t *child = ci->children + i;
 
-    if ((child->values_num != 1) ||
-        (child->values[0].type != OCONFIG_TYPE_STRING)) {
-      ERROR("write_stackdriver plugin: Resource labels must have exactly one "
-            "string "
-            "value. Ignoring label \"%s\".",
-            child->key);
-      continue;
-    }
+    if (strcasecmp("Label", child->key) == 0) {
+      if ((child->values_num != 2) ||
+          (child->values[0].type != OCONFIG_TYPE_STRING) ||
+          (child->values[1].type != OCONFIG_TYPE_STRING)) {
+        ERROR("write_stackdriver plugin: The \"Label\" option needs exactly "
+              "two string arguments.");
+        continue;
+      }
 
-    sd_resource_add_label(cb->resource, child->key,
-                          child->values[0].value.string);
+      sd_resource_add_label(cb->resource, child->values[0].value.string,
+                            child->values[1].value.string);
+    }
   }
 
   return 0;
-- 
2.11.0