stackdriver: add cloud_logging_base_url

Add the `Cloud_Logging_Base_Url` configuration option to the
`out_stackdriver` plugin.

Signed-off-by: braydonk <[email protected]>

plugins/out_stackdriver/stackdriver.c

@@ -1243,7 +1243,7 @@ static int cb_stackdriver_init(struct flb_output_instance *ins,
     pthread_mutex_init(&ctx->token_mutex, NULL);
 
     /* Create Upstream context for Stackdriver Logging (no oauth2 service) */
-    ctx->u = flb_upstream_create_url(config, FLB_STD_WRITE_URL,
+    ctx->u = flb_upstream_create_url(config, ctx->cloud_logging_write_url,
                                      io_flags, ins->tls);
     ctx->metadata_u = flb_upstream_create_url(config, ctx->metadata_server,
                                               FLB_IO_TCP, NULL);
@@ -3241,6 +3241,11 @@ static struct flb_config_map config_map[] = {
       0, FLB_TRUE, offsetof(struct flb_stackdriver, test_log_entry_format),
       "Test log entry format"
     },
+    {
+      FLB_CONFIG_MAP_STR, "cloud_logging_base_url", (char *)NULL,
+      0, FLB_TRUE, offsetof(struct flb_stackdriver, cloud_logging_base_url),
+      "The base Cloud Logging API URL to use for the /v2/entries:write API request. Default: https://logging.googleapis.com"
+    },
     /* EOF */
     {0}
 };

plugins/out_stackdriver/stackdriver.h

@@ -40,6 +40,7 @@
 
 /* Stackdriver Logging 'write' end-point */
 #define FLB_STD_WRITE_URI "/v2/entries:write"
+#define FLB_STD_WRITE_URI_SIZE 17
 #define FLB_STD_WRITE_URL "https://logging.googleapis.com" FLB_STD_WRITE_URI
 
 /* Timestamp format */
@@ -213,6 +214,10 @@ struct flb_stackdriver {
     /* the key to extract unstructured text payload from */
     flb_sds_t text_payload_key;
 
+    /* config key to allow an alternate Cloud Logging URL */
+    flb_sds_t cloud_logging_base_url;
+    flb_sds_t cloud_logging_write_url;
+
 #ifdef FLB_HAVE_METRICS
     /* metrics */
     struct cmt_counter *cmt_successful_requests;

plugins/out_stackdriver/stackdriver_conf.c

@@ -263,6 +263,8 @@ struct flb_stackdriver *flb_stackdriver_conf_create(struct flb_output_instance *
     struct flb_stackdriver *ctx;
     size_t http_request_key_size;
     struct cmt_histogram_buckets *buckets;
+    flb_sds_t cloud_logging_base_url_str;
+    size_t cloud_logging_base_url_size, cloud_logging_write_url_size;
 
     /* Allocate config context */
     ctx = flb_calloc(1, sizeof(struct flb_stackdriver));
@@ -272,7 +274,7 @@ struct flb_stackdriver *flb_stackdriver_conf_create(struct flb_output_instance *
     }
     ctx->ins = ins;
     ctx->config = config;
-    
+
     ret = flb_output_config_map_set(ins, (void *)ctx);
     if (ret == -1) {
         flb_plg_error(ins, "unable to load configuration");
@@ -460,6 +462,36 @@ struct flb_stackdriver *flb_stackdriver_conf_create(struct flb_output_instance *
         }
     }
 
+    if (ctx->cloud_logging_base_url) {
+        /*
+         * An alternate base URL was specified in the config. To avoid the confusion of a user
+         * not knowing whether the trailing `/` should be present, check whether the user
+         * provided it and remove it if it is.
+         */
+        cloud_logging_base_url_size = flb_sds_len(ctx->cloud_logging_base_url);
+        if (FLB_SDS_HEADER(
+                ctx->cloud_logging_base_url
+            )->buf[cloud_logging_base_url_size-1] == '/') {
+            cloud_logging_base_url_size -= 1;
+        }
+        cloud_logging_base_url_str = flb_sds_create_size(cloud_logging_base_url_size);
+
+        /* Note: The size calculated from `flb_sds_len` does not include the null terminator character,
+         * `size` argument for `flb_sds_snprintf` needs to be the size including the null terminator.
+         * Hence the +1 added to each size argument here.
+         */
+        flb_sds_snprintf(&cloud_logging_base_url_str, cloud_logging_base_url_size+1,
+                         "%s", ctx->cloud_logging_base_url);
+        cloud_logging_write_url_size = cloud_logging_base_url_size + FLB_STD_WRITE_URI_SIZE;
+        ctx->cloud_logging_write_url = flb_sds_create_size(cloud_logging_write_url_size);
+        flb_sds_snprintf(&ctx->cloud_logging_write_url, cloud_logging_write_url_size+1,
+                         "%s%s", cloud_logging_base_url_str, FLB_STD_WRITE_URI);
+
+        flb_sds_destroy(cloud_logging_base_url_str);
+    } else {
+        ctx->cloud_logging_write_url = flb_sds_create(FLB_STD_WRITE_URL);
+    }
+
     set_resource_type(ctx);
 
     if (resource_api_has_required_labels(ctx) == FLB_FALSE) {
@@ -473,7 +505,7 @@ struct flb_stackdriver *flb_stackdriver_conf_create(struct flb_output_instance *
             }
         }
 
-        else if (ctx->resource_type == RESOURCE_TYPE_GENERIC_NODE 
+        else if (ctx->resource_type == RESOURCE_TYPE_GENERIC_NODE
             || ctx->resource_type == RESOURCE_TYPE_GENERIC_TASK) {
 
             if (ctx->location == NULL) {
@@ -513,7 +545,6 @@ struct flb_stackdriver *flb_stackdriver_conf_create(struct flb_output_instance *
         }
     }
 
-
     if (ctx->tag_prefix == NULL && ctx->resource_type == RESOURCE_TYPE_K8S) {
         /* allocate the flb_sds_t to tag_prefix_k8s so we can safely deallocate it */
         ctx->tag_prefix_k8s = flb_sds_create(ctx->resource);
@@ -639,7 +670,7 @@ int flb_stackdriver_conf_destroy(struct flb_stackdriver *ctx)
         flb_sds_destroy(ctx->node_name);
         flb_sds_destroy(ctx->local_resource_id);
     }
-    
+
     if (ctx->metadata_server_auth) {
         flb_sds_destroy(ctx->zone);
         flb_sds_destroy(ctx->instance_id);
@@ -660,15 +691,19 @@ int flb_stackdriver_conf_destroy(struct flb_stackdriver *ctx)
     if (ctx->regex) {
         flb_regex_destroy(ctx->regex);
     }
-    
+
     if (ctx->project_id) {
         flb_sds_destroy(ctx->project_id);
     }
-    
+
     if (ctx->tag_prefix_k8s) {
         flb_sds_destroy(ctx->tag_prefix_k8s);
     }
 
+    if (ctx->cloud_logging_write_url) {
+        flb_sds_destroy(ctx->cloud_logging_write_url);
+    }
+
     flb_kv_release(&ctx->config_labels);
     flb_kv_release(&ctx->resource_labels_kvs);
     flb_free(ctx);