Restore bootstrap pre-release support

It was originally removed after discussion in community slack,
but it turns out to have a little more utility than we thought.
When enabled, it will cause the package to be downloaded from
the `current` channel.

Option description has been updated from 'install prerelease gem'
to 'install from current channel'.

This commit otherwise restores the original behavior and adds some tests.

Signed-off-by: Marc A. Paradise <marc.paradise@gmail.com>

6 files changed, 86 insertions, 14 deletions

diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index b0913a2a2f..ff598126af 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -131,7 +131,6 @@ Using removed options will cause the command to fail.
 |--kerberos-keytab-file| This option existed but was not implemented.|
 |--winrm-codepage| This was used under knife-windows because bootstrapping was performed over a `cmd` shell. It is now invoked from `powershell`, so this option is no longer used.|
 |--winrm-shell|This option was ignored for bootstrap.|
-|--prerelease|Chef now releases all development builds to our current channel and does not perform pre-release gem releases.|
 |--install-as-service|Installing Chef client as a service is not supported|
 
 #### Usage Changes
diff --git a/lib/chef/knife/bootstrap.rb b/lib/chef/knife/bootstrap.rb
index 69d9ffb8c0..701c207503 100644
--- a/lib/chef/knife/bootstrap.rb
+++ b/lib/chef/knife/bootstrap.rb
@@ -156,6 +156,10 @@ class Chef
         description: "The version of #{Chef::Dist::PRODUCT} to install.",
         proc: lambda { |v| Chef::Config[:knife][:bootstrap_version] = v }
 
+      option :prerelease,
+        long: "--prerelease",
+        description: "Install from 'current' channel"
+
       # client.rb content via chef-full/bootstrap_context
       option :bootstrap_proxy,
         long: "--bootstrap-proxy PROXY_URL",
diff --git a/lib/chef/knife/core/bootstrap_context.rb b/lib/chef/knife/core/bootstrap_context.rb
index dcca7b8a69..c46a6bc079 100644
--- a/lib/chef/knife/core/bootstrap_context.rb
+++ b/lib/chef/knife/core/bootstrap_context.rb
@@ -190,13 +190,24 @@ class Chef
         # chef version string to fetch the latest current version from omnitruck
         # If user is on X.Y.Z, bootstrap will use the latest X release
         def latest_current_chef_version_string
-          chef_version_string = if knife_config[:bootstrap_version]
-                                  knife_config[:bootstrap_version]
-                                else
-                                  Chef::VERSION.split(".").first
-                                end
+          installer_version_string = nil
+          if @config[:prerelease]
+            installer_version_string = ["-p"]
+          else
+            chef_version_string = if knife_config[:bootstrap_version]
+                                    knife_config[:bootstrap_version]
+                                  else
+                                    Chef::VERSION.split(".").first
+                                  end
+
+            installer_version_string = ["-v", chef_version_string]
 
-          "-v #{chef_version_string}"
+            # If bootstrapping a pre-release version add -p to the installer string
+            if chef_version_string.split(".").length > 3
+              installer_version_string << "-p"
+            end
+          end
+          installer_version_string.join(" ")
         end
 
         def first_boot
diff --git a/lib/chef/knife/core/windows_bootstrap_context.rb b/lib/chef/knife/core/windows_bootstrap_context.rb
index 6054743106..c6b8bc4d2b 100644
--- a/lib/chef/knife/core/windows_bootstrap_context.rb
+++ b/lib/chef/knife/core/windows_bootstrap_context.rb
@@ -159,13 +159,25 @@ class Chef
         end
 
         def latest_current_windows_chef_version_query
-          chef_version_string = if knife_config[:bootstrap_version]
-                                  knife_config[:bootstrap_version]
-                                else
-                                  Chef::VERSION.split(".").first
-                                end
+          installer_version_string = nil
+          if @config[:prerelease]
+            installer_version_string = "&prerelease=true"
+          else
+            chef_version_string = if knife_config[:bootstrap_version]
+                                    knife_config[:bootstrap_version]
+                                  else
+                                    Chef::VERSION.split(".").first
+                                  end
+
+            installer_version_string = "&v=#{chef_version_string}"
+
+            # If bootstrapping a pre-release version add the prerelease query string
+            if chef_version_string.split(".").length > 3
+              installer_version_string << "&prerelease=true"
+            end
+          end
 
-          "&v=#{chef_version_string}"
+          installer_version_string
         end
 
         def win_wget
diff --git a/spec/unit/knife/core/bootstrap_context_spec.rb b/spec/unit/knife/core/bootstrap_context_spec.rb
index 2ed8b6bc51..e72acf9b7a 100644
--- a/spec/unit/knife/core/bootstrap_context_spec.rb
+++ b/spec/unit/knife/core/bootstrap_context_spec.rb
@@ -166,6 +166,27 @@ describe Chef::Knife::Core::BootstrapContext do
     it "should send the full version to the installer" do
       expect(bootstrap_context.latest_current_chef_version_string).to eq("-v 11.12.4")
     end
+
+    describe "and it is a prerelease version" do
+      let(:chef_config) do
+        {
+          knife: { bootstrap_version: "11.12.4.xyz" },
+        }
+      end
+
+      it "should set the version and set -p" do
+        expect(bootstrap_context.latest_current_chef_version_string).to eq("-v 11.12.4.xyz -p")
+      end
+    end
+
+  end
+
+  describe "when prerelease is specified" do
+    let(:config) { { prerelease: true } }
+
+    it "should send -p to the installer" do
+      expect(bootstrap_context.latest_current_chef_version_string).to eq("-p")
+    end
   end
 
   describe "when a bootstrap_version is not specified" do
diff --git a/spec/unit/knife/core/windows_bootstrap_context_spec.rb b/spec/unit/knife/core/windows_bootstrap_context_spec.rb
index a19ad11247..a39a3a9242 100644
--- a/spec/unit/knife/core/windows_bootstrap_context_spec.rb
+++ b/spec/unit/knife/core/windows_bootstrap_context_spec.rb
@@ -177,11 +177,36 @@ describe Chef::Knife::Core::WindowsBootstrapContext do
   end
 
   describe "latest_current_windows_chef_version_query" do
-    it "returns the major version of the current version of Chef" do
+    it "includes the major version of the current version of Chef" do
       stub_const("Chef::VERSION", "15.1.2")
       expect(bootstrap_context.latest_current_windows_chef_version_query).to eq("&v=15")
     end
 
+    context "when bootstrap_version is given" do
+      before do
+        Chef::Config[:knife][:bootstrap_version] = "15.1.2"
+      end
+      it "includes the requested version" do
+        expect(bootstrap_context.latest_current_windows_chef_version_query).to eq("&v=15.1.2")
+      end
+    end
+
+    context "when prerelease is true" do
+      let(:config) { { prerelease: true } }
+      it "includes prerelease indicator " do
+        expect(bootstrap_context.latest_current_windows_chef_version_query).to eq("&prerelease=true")
+      end
+    end
+
+    context "when a prerelease bootstrap_version is specified" do
+      before do
+        Chef::Config[:knife][:bootstrap_version] = "15.1.2.xyz"
+      end
+      it "includes prerelease indicator and the given version" do
+        expect(bootstrap_context.latest_current_windows_chef_version_query).to eq("&v=15.1.2.xyz&prerelease=true")
+      end
+    end
+
   end
 
   describe "msi_url" do