Add support for connection strings

Dockerfile

@@ -18,6 +18,7 @@ RUN echo "<source>\n\
   @type azure-storage-append-blob\n\
   azure_storage_account             \"#{ENV['STORAGE_ACCOUNT']}\"\n\
   azure_storage_access_key          \"#{ENV['STORAGE_ACCESS_KEY']}\"\n\
+  azure_storage_connection_string   \"#{ENV['STORAGE_CONNECTION_STRING']}\"\n\
   azure_storage_sas_token           \"#{ENV['STORAGE_SAS_TOKEN']}\"\n\
   azure_container                   fluentd\n\
   auto_create_container             true\n\

README.md

@@ -27,6 +27,7 @@ And then execute:
 
       azure_storage_account             <your azure storage account>
       azure_storage_access_key          <your azure storage access key> # leave empty to use MSI
+      azure_storage_connection_string   <your azure storage connection string> # leave empty to use MSI
       azure_storage_sas_token           <your azure storage sas token> # leave empty to use MSI
       azure_imds_api_version            <Azure Instance Metadata Service API Version> # only used for MSI
       azure_token_refresh_interval      <refresh interval in min> # only used for MSI
@@ -50,12 +51,12 @@ And then execute:
 
 Your Azure Storage Account Name. This can be retrieved from Azure Management portal.
 
-### `azure_storage_access_key` or `azure_storage_sas_token` (Either required or both empty to use MSI)
+### `azure_storage_access_key` or `azure_storage_sas_token` or `azure_storage_connection_string` (Any required or all empty to use MSI)
 
-Your Azure Storage Access Key (Primary or Secondary) or shared access signature (SAS) token.
+Your Azure Storage Access Key (Primary or Secondary) or shared access signature (SAS) token or full connection string.
 This also can be retrieved from Azure Management portal.
 
-If both are empty, the plugin will use the local Managed Identity endpoint to obtain a token for the target storage account.
+If all are empty, the plugin will use the local Managed Identity endpoint to obtain a token for the target storage account.
 
 ### `azure_imds_api_version` (Optional, only for MSI)
 

lib/fluent/plugin/out_azure-storage-append-blob.rb

@@ -23,6 +23,7 @@ class AzureStorageAppendBlobOut < Fluent::Plugin::Output
       config_param :azure_storage_account, :string, default: nil
       config_param :azure_storage_access_key, :string, default: nil, secret: true
       config_param :azure_storage_sas_token, :string, default: nil, secret: true
+      config_param :azure_storage_connection_string, :string, default: nil, secret: true
       config_param :azure_container, :string, default: nil
       config_param :azure_imds_api_version, :string, default: '2019-08-15'
       config_param :azure_token_refresh_interval, :integer, default: 60
@@ -63,7 +64,9 @@ def configure(conf)
 
         raise ConfigError, 'azure_container needs to be specified' if @azure_container.nil?
 
-        if (@azure_storage_access_key.nil? || @azure_storage_access_key.empty?) && (@azure_storage_sas_token.nil? || @azure_storage_sas_token.empty?)
+        if (@azure_storage_access_key.nil? || @azure_storage_access_key.empty?) &&
+           (@azure_storage_sas_token.nil? || @azure_storage_sas_token.empty?) &&
+           (@azure_storage_connection_string.nil? || @azure_storage_connection_string.empty?)
           log.info 'Using MSI since neither azure_storage_access_key nor azure_storage_sas_token was provided.'
           @use_msi = true
         end
@@ -102,6 +105,8 @@ def start
           end
           sleep 0.1 while renew_token.status != 'sleep'
           renew_token.run
+        elsif !@azure_storage_connection_string.nil? && !@azure_storage_connection_string.empty?
+          @bs = Azure::Storage::Blob::BlobService.create_from_connection_string(@azure_storage_connection_string)
         else
           @bs_params = { storage_account_name: @azure_storage_account }
 
@@ -112,6 +117,7 @@ def start
           end
 
           @bs = Azure::Storage::Blob::BlobService.create(@bs_params)
+
         end
 
         ensure_container
@@ -142,25 +148,21 @@ def write(chunk)
           append_blob(content, metadata)
           @last_azure_storage_path = @azure_storage_path
         ensure
-          begin
-            tmp.close(true)
-          rescue StandardError
-            nil
-          end
+          tmp.close(true) rescue nil
         end
       end
 
       def container_exists?(container)
         begin
           @bs.get_container_properties(container)
-        rescue Azure::Core::Http::HTTPError => ex
-          if ex.status_code == 404 # container does not exist
+        rescue Azure::Core::Http::HTTPError => e
+          if e.status_code == 404 # container does not exist
             return false
           else
             raise
           end
         end
-        return true
+        true
       end
 
       private
@@ -175,14 +177,12 @@ def ensure_container
         end
       end
 
-      private
-
       def generate_log_name(metadata, index)
         time_slice = if metadata.timekey.nil?
                        ''.freeze
                      else
                        Time.at(metadata.timekey).utc.strftime(@time_slice_format)
-          end
+                     end
 
         path = @path_slicer.call(@path)
         values_for_object_key = {
@@ -194,8 +194,6 @@ def generate_log_name(metadata, index)
         @azure_storage_path = extract_placeholders(storage_path, metadata)
       end
 
-      private
-
       def append_blob(content, metadata)
         position = 0
         log.debug "azure_storage_append_blob: append_blob.start: Content size: #{content.length}"