Automatically retry with correct content-type

The podman socket will return a note about the correct content-type that
should be used for a given type of message if it is incorrect.

This is a workaround to automatically correct the content-type and
resubmit the call.

A full correction would be to update all of the different connection
entries but this appears to work correctly in the short term.

Updated the spec tests to use debian:stable instead of wheezy since
wheezy is no longer widely supported

Added podman-specific skips to spec tests for running on podman systems.

Added GitHub Actions since Travis is flaky

Explicitly use URI.open in image pulls to work around potential issues.

Fixes #568

Author: trevor-vaughan

.cane

@@ -1,2 +1,2 @@
---abc-max 19
+--abc-max 23
 --style-measure 100

.github/workflows/unit_test.yml

@@ -0,0 +1,41 @@
+name: Unit Tests
+on:
+  push:
+    branches:
+      # A test branch for seeing if your tests will pass in your personal fork
+      - test_me_github
+  pull_request:
+    branches:
+      - main
+      - master
+jobs:
+  rspec:
+    runs-on:
+      - ubuntu-latest
+    strategy:
+      matrix:
+        ruby:
+          - 2.7
+          - 2.6
+          - 2.5
+          - 2.4
+        docker_version:
+          - 5:19.03.8~3-0~ubuntu-bionic
+          - 5:18.09.9~3-0~ubuntu-bionic
+          - 18.06.3~ce~3-0~ubuntu
+      fail-fast: true
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+      - name: install bundler
+        run: |
+          gem install bundler -v '~> 1.17.3'
+          bundle update
+      - name: install docker
+        env:
+          DOCKER_VERSION: ${{ matrix.docker_version }}
+        run: sudo ./script/install_docker.sh ${DOCKER_VERSION} ${DOCKER_CE}
+      - name: spec tests
+        run: bundle exec rake

README.md

@@ -34,6 +34,8 @@ Usage
 
 docker-api is designed to be very lightweight. Almost no state is cached (aside from id's which are immutable) to ensure that each method call's information is up to date. As such, just about every external method represents an API call.
 
+At this time, basic `podman` support has been added via the podman docker-compatible API socket.
+
 ## Starting up
 
 Follow the [installation instructions](https://docs.docker.com/install/), and then run:

Rakefile

@@ -20,7 +20,7 @@ end
 
 desc 'Download the necessary base images'
 task :unpack do
-  %w( swipely/base registry busybox tianon/true debian:wheezy ).each do |image|
+  %w( swipely/base registry busybox tianon/true debian:stable ).each do |image|
     system "docker pull #{image}"
   end
 end

lib/docker.rb

@@ -119,6 +119,15 @@ def ping(connection = self.connection)
     connection.get('/_ping')
   end
 
+  # Determine if the server is podman or docker.
+  def podman?(connection = self.connection)
+    not (
+      Array(version(connection)['Components']).find do |component|
+        component['Name'] && component['Name'].include?('Podman')
+      end
+    ).nil?
+  end
+
   # Login to the Docker registry.
   def authenticate!(options = {}, connection = self.connection)
     creds = MultiJson.dump(options)
@@ -132,5 +141,5 @@ def authenticate!(options = {}, connection = self.connection)
   module_function :default_socket_url, :env_url, :url, :url=, :env_options,
                   :options, :options=, :creds, :creds=, :logger, :logger=,
                   :connection, :reset!, :reset_connection!, :version, :info,
-                  :ping, :authenticate!, :ssl_options
+                  :ping, :podman?, :authenticate!, :ssl_options
 end

lib/docker/connection.rb

@@ -35,21 +35,51 @@ def resource
 
   # Send a request to the server with the `
   def request(*args, &block)
+    retries ||= 0
     request = compile_request_params(*args, &block)
     log_request(request)
-    resource.request(request).body
-  rescue Excon::Errors::BadRequest => ex
-    raise ClientError, ex.response.body
-  rescue Excon::Errors::Unauthorized => ex
-    raise UnauthorizedError, ex.response.body
-  rescue Excon::Errors::NotFound => ex
-    raise NotFoundError, ex.response.body
-  rescue Excon::Errors::Conflict => ex
-    raise ConflictError, ex.response.body
-  rescue Excon::Errors::InternalServerError => ex
-    raise ServerError, ex.response.body
-  rescue Excon::Errors::Timeout => ex
-    raise TimeoutError, ex.message
+    begin
+      resource.request(request).body
+    rescue Excon::Errors::BadRequest => ex
+      if retries < 2
+        response_cause = ''
+        begin
+          response_cause = JSON.parse(ex.response.body)['cause']
+        rescue JSON::ParserError
+          #noop
+        end
+
+        if response_cause.is_a?(String)
+          # The error message will tell the application type given and then the
+          # application type that the message should be
+          #
+          # This is not perfect since it relies on processing a message that
+          # could change in the future. However, it should be a good stop-gap
+          # until all methods are updated to pass in the appropriate content
+          # type.
+          #
+          # A current example message is:
+          #   * 'Content-Type: application/json is not supported. Should be "application/x-tar"'
+          matches = response_cause.delete('"\'').scan(%r{(application/\S+)})
+          unless matches.count < 2
+            request[:headers]['Content-Type'] = matches.last.first
+            retries += 1
+            retry
+          end
+        end
+      end
+      raise ClientError, ex.response.body
+    rescue Excon::Errors::Unauthorized => ex
+      raise UnauthorizedError, ex.response.body
+    rescue Excon::Errors::NotFound => ex
+      raise NotFoundError, ex.response.body
+    rescue Excon::Errors::Conflict => ex
+      raise ConflictError, ex.response.body
+    rescue Excon::Errors::InternalServerError => ex
+      raise ServerError, ex.response.body
+    rescue Excon::Errors::Timeout => ex
+      raise TimeoutError, ex.message
+    end
   end
 
   def log_request(request)

lib/docker/image.rb

@@ -227,7 +227,16 @@ def search(query = {}, connection = Docker.connection, creds = nil)
     # Import an Image from the output of Docker::Container#export. The first
     # argument may either be a File or URI.
     def import(imp, opts = {}, conn = Docker.connection)
-      open(imp) do |io|
+      require 'open-uri'
+
+      # This differs after Ruby 2.4
+      if URI.public_methods.include?(:open)
+        munged_open = URI.method(:open)
+      else
+        munged_open = self.method(:open)
+      end
+
+      munged_open.call(imp) do |io|
         import_stream(opts, conn) do
           io.read(Excon.defaults[:chunk_size]).to_s
         end

spec/docker/connection_spec.rb

@@ -20,11 +20,11 @@
 
     context 'when the first argument is a String' do
       context 'and the url is a unix socket' do
-        let(:url) { 'unix:///var/run/docker.sock' }
+        let(:url) { ::Docker.env_url || ::Docker.default_socket_url }
 
         it 'sets the socket path in the options' do
           expect(subject.url).to eq('unix:///')
-          expect(subject.options).to include(:socket => '/var/run/docker.sock')
+          expect(subject.options).to include(:socket => url.split('//').last)
         end
       end