Follow the Step-by-Step Guide given below for Confluence Single Sign On (SSO) using Google Apps as IdP

STEP 1: Configuring Google Apps as IdP

• Go to https://admin.google.com and login to your Google Apps Administrator account.
• On the Admin Home, select More Controls Apps.



• In the App Settings, select SAML apps.
• Click on the "+" button at the bottom right corner to create a new SAML app.
• Now select SETUP MY OWN CUSTOM APP from the popup.
• On the next screen, note down the SSO URL, Entity ID URLs and download the certificate. These will be required while configuring the Plugin.
• Once you have noted down the URLs and downloaded the certificate, click on Next.
• Enter the Application Name and Description. Click on Next.
• Configure the following things on the next screen:
  
  

  ACS URL	ACS (Assertion Consumer Service) URL from Step1 of the plugin under Configure IDP Tab.
  Entity ID	SP-EntityID / Issuer from Step1 of the plugin under Configure IDP Tab.
  Signed Response	Checked
  Name ID	Select Basic Information from the first dropdown. Then Primary Email from the second dropdown.

  
  
  
• Click on Next. Then click on Finish.
• Now go to SAML Apps again. Click on the menu link corresponding to your app (See the screenshot). Then select ON for everyone.
  
  
  
• From the popup, Click on TURN ON FOR EVERYONE.

STEP 2: Configuring Confluence as SP

• In miniOrange SAML plugin, go to Configure SP Tab. Enter the following values:
  
  

  IDP Entity ID:	The Entity ID that you noted down while configuring the Confluence site in Google Apps.
  Single Sign On URL:	The SSO URL that you noted down while configuring the Confluence site in Google Apps.
  Single Logout URL:	The Single Logout URL that you noted down while configuring the Confluence site in Google Apps.
  X.509 Certificate:	Open the .cer certificate file in notepad and copy/paste the entire content of the file.

• In miniOrange SAML plugin, go to Attribute Mapping tab. Enter the following values:
  
  

  Username:	Name of the username attribute from IDP (Keep Username as NameID by default)
  Email:	Name of the email attribute from IDP (Keep Email as NameID by default)
  FirstName:	Name of the firstname attribute from IDP
  LastName:	Name of the lastname attribute from IDP




• Go to Role Mapping tab. Enter the following values:

Role Mapping

Name of the Role attribute from IDP

• You can check the Test Configuration Results to get a better idea as to which values to map here.
• Under the Role Mapping Section configure which GROUP value coming in the SAML response needs to be mapped to which role. The Group value coming in the SAML response will be mapped to the Role assigned here and the user will be assigned that role.



• Go to Sign In Settings tab. Enable auto-redirect to IDP using Disable Confluence login option.

For further details refer :

"https://confluence.atlassian.com/crowd/configuring-the-google-apps-connector-167182631.html"
" https://confluence.atlassian.com/cloud/integrate-with-g-suite-744721642.html "