How to configure Endorsement policy in Hyperledger

Question

I am trying to implement Hyperledger Fabric on my system. I am not understanding how to configure the Endorsement policy for the Hyperledger Fabric. Can someone explain how to configure the endorsement policy?

Answer 1

The Hyperledger Fabric Endorsement policy is configured when the chaincode is instantiated. The Endorsement policies are configured as logical gate predicates. The rule for this logic gate is as follows:

EXPR(E[, E...]) where EXPR is AND or OR and E is either a principal (Org1.Admin, Org1.Member) or a nested expression EXPR(..)

Example: 

"AND('Org1.member', 'Org2.member')"

When you execute

peer instantiate chaincodeName

you have to pass

-P policyString

where policyString is the expression shown as in the above example

Ex:

peer chaincode instantiate -C testchainid -n mycc -p github.com/hyperledger/fabric/examples/chaincode/go/chaincode_example02 -c '{"Args":["init","a","100","b","200"]}' -P "AND('Org1.member', 'Org2.member')"

Comments

What the logic 

-P "AND('Org1.member', 'Org2.member')"

in your code mean?

---

Hi @Shri, it means that both Org1 and Org2 members are requested to sign the transaction.

---

Hi. I want to write a logic for the following case. I have two Organizations Org1 and Org2. I want either one of them to sign the transaction i.e., it is not necessary that both should sign the transaction. What is the logic for this?

---

You can use the OR gate for this. Refer the below logic.

-P "AND('Org1.member', 'Org2.member')"

---

You can also use nested logic. Suppose you want to request one signature from a member of the Org1 MSP or 1 signature from a member of the Org2 MSP and 1 signature from a member of the Org3 MSP. Then you can use the following logic:

OR('Org1.member', AND('Org2.member', 'Org3.member'))

Answer 2

Endorsement policy can be set by using the -P switch. When instantiating the chaincode, use the -P switch following by a Boolean logic representing which peer or organization has to sign the transaction. 

$ peer chaincode instantiate <other parameters> -P <boolean logic>