VCL 108: Hash, Hit, Miss and Pass Subroutines

Course Details

Overview of the Hash, Hit, Miss, & Pass Subroutines of VCL. 

Learning Objectives

• Adding Hash to the Flow
  • Hash Key Generation and modification
  • When/where to change your Hash Key inputs
    • before/after vcl_hash
  • With Shielding
• Adding Hit to the Flow
  • Is it in Cache? Yes
  • But I can still Pass?
  • Straight to Deliver
• Adding Miss to the Flow
  • Not in Cache
  • Last-minute changes to the request before being sent to the backend
    • Changes to Host/URL/Hash Key in Recv vc Miss
    • The shield might be your backend
  • Object Fetch - not a subroutine
• Adding Pass to the Flow
  
  • Recv, Hit, Miss > Pass
  • Don’t want to cache
  • Last-minute changes to the request before being sent to the backend
    • Changes to Host/URL/Hash Key in Recv vc Miss
  • Object Fetch - not a subroutine