Simplify integration testing

Dockerfile

@@ -0,0 +1,36 @@
+FROM ruby:latest
+
+WORKDIR /plugin
+
+ADD . /plugin
+
+RUN gem install bundler && \
+    gem install fluentd --no-doc && \
+    fluent-gem build fluent-plugin-azure-storage-append-blob.gemspec && \
+    fluent-gem install fluent-plugin-azure-storage-append-blob-*.gem
+
+RUN echo "<source>\n\
+  @type sample\n\
+  sample {\"hello\":\"world\"}\n\
+  tag pattern\n\
+</source>\n\
+<match pattern>\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_sas_token           \"#{ENV['STORAGE_SAS_TOKEN']}\"\n\
+  azure_container                   fluentd\n\
+  auto_create_container             true\n\
+  path                              logs/\n\
+  azure_object_key_format           %{path}%{time_slice}_%{index}.log\n\
+  time_slice_format                 %Y%m%d-%H\n\
+  <buffer tag,time>\n\
+    @type file\n\
+    path /var/log/fluent/azurestorageappendblob\n\
+    timekey 120 # 2 minutes\n\
+    timekey_wait 60\n\
+    timekey_use_utc true # use utc\n\
+  </buffer>\n\
+</match>" > /plugin/fluent.conf
+
+ENTRYPOINT ["fluentd", "-c", "fluent.conf"]

README.md

@@ -128,6 +128,33 @@ Format of the time used in the file name. Default is '%Y%m%d'. Use '%Y%m%d%H' to
     bundle install
     bundle exec rake test
 
+
+### Test Fluentd
+
+1. Create Storage Account and VM with enabled MSI
+2. Setup Docker ang Git
+3. SSH into VM
+4. Download this repo
+   ```
+   git clone https://github.com/microsoft/fluent-plugin-azure-storage-append-blob.git
+   cd fluent-plugin-azure-storage-append-blob
+   ```
+5. Build Docker image
+   `docker build -t fluent .`
+6. Run Docker image with different set of parameters:
+
+    1. `STORAGE_ACCOUNT`: required, name of your storage account
+    2. `STORAGE_ACCESS_KEY`: storage account access key
+    3. `STORAGE_SAS_TOKEN`: storage sas token with enough permissions for the plugin
+
+    You need to specify `STORAGE_ACCOUNT` and one of auth ways. If you run it from VM with MSI,
+    just `STORAGE_ACCOUNT` is required. Keep in mind, there is no way to refresh MSI Token, so
+    ensure you setup proper permissions first.
+
+    ```bash
+    docker run -it -e STORAGE_ACCOUNT=<storage> -e STORAGE_ACCESS_KEY=<key> fluent
+    ```
+
 ## Contributing
 
 This project welcomes contributions and suggestions.  Most contributions require you to agree to a

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

@@ -63,7 +63,7 @@ def configure(conf)
 
         raise ConfigError, 'azure_container needs to be specified' if @azure_container.nil?
 
-        if @azure_storage_access_key.nil? && @azure_storage_sas_token.nil?
+        if (@azure_storage_access_key.nil? || @azure_storage_access_key.empty?) && (@azure_storage_sas_token.nil? || @azure_storage_sas_token.empty?)
           log.info 'Using MSI since neither azure_storage_access_key nor azure_storage_sas_token was provided.'
           @use_msi = true
         end
@@ -105,9 +105,9 @@ def start
         else
           @bs_params = { storage_account_name: @azure_storage_account }
 
-          if !@azure_storage_access_key.nil?
+          if !@azure_storage_access_key.nil? && !@azure_storage_access_key.empty?
             @bs_params.merge!({ storage_access_key: @azure_storage_access_key })
-          elsif !@azure_storage_sas_token.nil?
+          elsif !@azure_storage_sas_token.nil? && !@azure_storage_sas_token.empty?
             @bs_params.merge!({ storage_sas_token: @azure_storage_sas_token })
           end