Better target mode no-creds errorslcg/better-target-mode-creds-errors

Changes the target mode error in the case of no creds at all to:

```
FATAL: ArgumentError: Credentials file specified for target mode does not exist: '/Users/lamont/.chef/credentials'
```

From:

```
[2019-05-20T17:30:41-07:00] FATAL: NoMethodError: undefined method `[]' for nil:NilClass
```

Signed-off-by: Lamont Granquist <lamont@scriptkiddie.org>

2 files changed, 24 insertions, 23 deletions

diff --git a/lib/chef/train_transport.rb b/lib/chef/train_transport.rb
index 9db5f8fbf3..95b5018960 100644
--- a/lib/chef/train_transport.rb
+++ b/lib/chef/train_transport.rb
@@ -20,12 +20,12 @@ require "train"
 
 class Chef
   class TrainTransport
+    extend ChefConfig::Mixin::Credentials
+
     #
     # Returns a RFC099 credentials profile as a hash
     #
     def self.load_credentials(profile)
-      extend ChefConfig::Mixin::Credentials
-
       # Tomlrb.load_file returns a hash with keys as strings
       credentials = parse_credentials_file
       if contains_split_fqdn?(credentials, profile)
@@ -74,22 +74,18 @@ class Chef
       profile = tm_config.host
 
       credentials_file =
-        if tm_config.credentials_file
-          if File.exists?(tm_config.credentials_file)
-            tm_config.credentials_file
-          else
-            raise ArgumentError, "Credentials file specified for target mode does not exist: '#{tm_config.credentials_file}'"
-          end
-        elsif File.exists?(Chef::Config.platform_specific_path("/etc/chef/#{profile}/credentials"))
+        if tm_config.credentials_file && File.exist?(tm_config.credentials_file)
+          tm_config.credentials_file
+        elsif File.exist?(Chef::Config.platform_specific_path("/etc/chef/#{profile}/credentials"))
           Chef::Config.platform_specific_path("/etc/chef/#{profile}/credentials")
         else
           super
         end
-      if credentials_file
-        Chef::Log.debug("Loading credentials file '#{credentials_file}' for target '#{profile}'")
-      else
-        Chef::Log.debug("No credentials file found for target '#{profile}'")
-      end
+
+      raise ArgumentError, "No credentials file found for target '#{profile}'" unless credentials_file
+      raise ArgumentError, "Credentials file specified for target mode does not exist: '#{credentials_file}'" unless File.exist?(credentials_file)
+
+      Chef::Log.debug("Loading credentials file '#{credentials_file}' for target '#{profile}'")
 
       credentials_file
     end
diff --git a/spec/unit/train_transport_spec.rb b/spec/unit/train_transport_spec.rb
index b56c7e1104..cc978d0b94 100644
--- a/spec/unit/train_transport_spec.rb
+++ b/spec/unit/train_transport_spec.rb
@@ -40,6 +40,7 @@ describe Chef::TrainTransport do
     # [foo.example.org]   => {"foo"=>{"example"=>{"org"=>{}}}}
     # ['foo.example.org'] => {"foo.example.org"=>{}}
     it "warns if the host has been split by toml" do
+      allow(Chef::TrainTransport).to receive(:credentials_file_path).and_return("/Users/scotthourglass/.chef/credentials")
       allow(Chef::TrainTransport).to receive(:parse_credentials_file).and_return({ "foo" => { "example" => { "org" => {} } } })
       expect(Chef::Log).to receive(:warn).with(/as a Hash/)
       expect(Chef::Log).to receive(:warn).with(/Hostnames must be surrounded by single quotes/)
@@ -48,32 +49,36 @@ describe Chef::TrainTransport do
   end
 
   describe "credentials_file_path" do
+    let(:config_cred_file_path) { "/somewhere/credentials" }
+    let(:host_cred_file_path) { "/etc/chef/foo.example.org/credentials" }
 
     context "when a file path is specified by a config" do
-      let(:cred_file_path) { "/somewhere/credentials" }
-
       before do
-        tm_config = double("Config Context", host: "foo.example.org", credentials_file: cred_file_path)
+        tm_config = double("Config Context", host: "foo.example.org", credentials_file: config_cred_file_path)
         allow(Chef::Config).to receive(:target_mode).and_return(tm_config)
       end
 
       it "returns the path if it exists" do
-        allow(File).to receive(:exists?).with(cred_file_path).and_return(true)
-        expect(Chef::TrainTransport.credentials_file_path).to eq(cred_file_path)
+        allow(File).to receive(:exist?).with(config_cred_file_path).and_return(true)
+        expect(Chef::TrainTransport.credentials_file_path).to eq(config_cred_file_path)
       end
 
       it "raises an error if it does not exist" do
-        allow(File).to receive(:exists?).with(cred_file_path).and_return(false)
+        allow(File).to receive(:exist?).and_return(false)
         expect { Chef::TrainTransport.credentials_file_path }.to raise_error(ArgumentError, /does not exist/)
       end
     end
 
+    it "raises an error if the default creds files do not exist" do
+      allow(File).to receive(:exist?).and_return(false)
+      expect { Chef::TrainTransport.credentials_file_path }.to raise_error(ArgumentError, /does not exist/)
+    end
+
     it "returns the path to the default config file if it exists" do
-      cred_file_path = Chef::Config.platform_specific_path("/etc/chef/foo.example.org/credentials")
       tm_config = double("Config Context", host: "foo.example.org", credentials_file: nil)
       allow(Chef::Config).to receive(:target_mode).and_return(tm_config)
-      allow(File).to receive(:exists?).with(cred_file_path).and_return(true)
-      expect(Chef::TrainTransport.credentials_file_path).to eq(cred_file_path)
+      allow(File).to receive(:exist?).with(host_cred_file_path).and_return(true)
+      expect(Chef::TrainTransport.credentials_file_path).to eq(host_cred_file_path)
     end
   end
 end