Added ssh fingerprint, gitlab ci and pages information in an instance configuration page

Closes #25142

1 files changed, 71 insertions, 0 deletions

diff --git a/app/models/instance_configuration.rb b/app/models/instance_configuration.rb
new file mode 100644
index 00000000000..b30b707e5fe
--- /dev/null
+++ b/app/models/instance_configuration.rb
@@ -0,0 +1,71 @@
+require 'resolv'
+
+class InstanceConfiguration
+  SSH_ALGORITHMS = %w(DSA ECDSA ED25519 RSA).freeze
+  SSH_ALGORITHMS_PATH = '/etc/ssh/'.freeze
+  CACHE_KEY = 'instance_configuration'.freeze
+  EXPIRATION_TIME = 24.hours
+
+  def settings
+    @configuration ||= Rails.cache.fetch(CACHE_KEY, expires_in: EXPIRATION_TIME) do
+      { ssh_algorithms_hashes: ssh_algorithms_hashes,
+        host: host,
+        gitlab_pages: gitlab_pages,
+        gitlab_ci: gitlab_ci }.deep_symbolize_keys
+    end
+  end
+
+  private
+
+  def ssh_algorithms_hashes
+    SSH_ALGORITHMS.map { |algo| ssh_algorithm_hashes(algo) }.compact
+  end
+
+  def host
+    Settings.gitlab.host
+  end
+
+  def gitlab_pages
+    Settings.pages.to_h.merge(ip_address: resolv_dns(Settings.pages.host))
+  end
+
+  def resolv_dns(dns)
+    Resolv.getaddress(dns)
+  rescue Resolv::ResolvError
+  end
+
+  def gitlab_ci
+    Settings.gitlab_ci
+            .to_h
+            .merge(artifacts_max_size: { value: Settings.artifacts.max_size&.megabytes,
+                                         default: 100.megabytes })
+  end
+
+  def ssh_algorithm_file(algorithm)
+    File.join(SSH_ALGORITHMS_PATH, "ssh_host_#{algorithm.downcase}_key.pub")
+  end
+
+  def ssh_algorithm_hashes(algorithm)
+    content = ssh_algorithm_file_content(algorithm)
+    return unless content.present?
+
+    { name: algorithm,
+      md5: ssh_algorithm_md5(content),
+      sha256: ssh_algorithm_sha256(content) }
+  end
+
+  def ssh_algorithm_file_content(algorithm)
+    file = ssh_algorithm_file(algorithm)
+    return unless File.exist?(file)
+
+    File.read(file)
+  end
+
+  def ssh_algorithm_md5(ssh_file_content)
+    OpenSSL::Digest::MD5.hexdigest(ssh_file_content).scan(/../).join(':')
+  end
+
+  def ssh_algorithm_sha256(ssh_file_content)
+    OpenSSL::Digest::SHA256.hexdigest(ssh_file_content)
+  end
+end