ES-692 Write technical document for signup service

Signed-off-by: pr <[email protected]>

README.md

@@ -1,14 +1,56 @@
 # esignet-signup
 
-signup-service is part of the esignet modules, but has a separate Helm chart so as to install and manage it in a completely independent namespace.
+Signup-service is part of the esignet modules, but has a separate Helm chart so as to install and manage it in a completely independent namespace.
+
+Signup-service is a spring boot application with endpoints to
+
+1. Generate Challenge (Only OTP supported)
+2. Verify Challenge
+3. Register user with verified transaction
+4. Check registration status
+5. Reset the password of the registered user
+
+Signup service connects to MOSIP IDRepo Identity service to register the verified user as an identity record.
+ID Repo identity service publishes the registered identity to MOSIP IDA. This enables authentication with the registered
+username and password with eSignet.
+
+Publishing registered/updated identity to MOSIP IDA is an async process. Hence, status endpoint is configured to check
+the latest status from server after every configured interval from signup UI.
+
+### Signup service uses spring cache to store the transaction details.
+
+Registration flow:
+
+| Endpoint          | Cache                                                                | Evict                                               |
+|-------------------|----------------------------------------------------------------------|-----------------------------------------------------|
+| generateChallenge | challenge-generated (k: transactionId, v: SignupTransaction)         |                                                     |
+| verifyChallenge   | challenge-verified (k: verified-transactionId, v: SignupTransaction)       | challenge-generated (k: transactionId, v: SignupTransaction)       |
+| register          | status-check (k: verified-transactionId, v: SignupTransaction) | challenge-verified (k: verified-transactionId, v: SignupTransaction) |
+| status            | status-check (k: verified-transactionId, v: SignupTransaction) |     |
+
+Reset Password flow:
+
+| Endpoint          | Cache                                                                      | Evict                                               |
+|-------------------|----------------------------------------------------------------------------|-----------------------------------------------------|
+| generateChallenge | challenge-generated (k: transactionId, v: SignupTransaction)         |                                                     |
+| verifyChallenge   | challenge-verified (k: verified-transactionId, v: SignupTransaction) | challenge-generated (k: transactionId, v: SignupTransaction)       |
+| resetPassword     | status-check (k: verified-transactionId, v: SignupTransaction)           | challenge-verified (k: verified-transactionId, v: SignupTransaction) |
+| status            | status-check (k: verified-transactionId, v: SignupTransaction)       |     |
 
 ## Build & run (for developers)
 The project requires JDK 11.
 1. Build and install:
     ```
     $ mvn clean install -Dgpg.skip=true
     ```
-1. Build Docker for a service:
+2. Run with IntelliJ IDEA
+
+   2.1 Right click on parent POM file (pom.xml) and click on button "Add as Maven Project".
+   2.2 Download kernel-auth-adapter-1.2.1-es-SNAPSHOT.jar file from https://oss.sonatype.org/#nexus-search;gav~io.mosip.kernel~kernel-auth-adapter~~~~kw,versionexpand
+   2.3 Add that file to "signup-service" in Project Structure settings of IntelliJ, and Apply.
+   2.4 right click on file signup-service/src/main/java/io/mosip/signup/SignUpServiceApplication.java and click on Run
+
+3. Build Docker for a service:
     ```
     $ docker build -f Dockerfile
     ```