feat: Add support for Transactions extension

This commit adds the "Transactions" extension to the Redis implementation. It includes the implementation of commands such as MULTI, EXEC, DISCARD, and handling failures within transactions. The extension also introduces stages for implementing the INCR command in multiple steps.

internal/test_helpers/course_definition.yml

@@ -89,6 +89,18 @@ extensions:
       [xadd-command]: https://redis.io/commands/xadd/
       [xrange-command]: https://redis.io/commands/xrange/
 
+  - slug: "transactions"
+    name: "Transactions"
+    description_markdown: |-
+      In this challenge extension you'll add support for [Transactions][redis-transactions] to your Redis implementation.
+      
+      Along the way, you'll learn about the [MULTI][multi-command], [EXEC][exec-command], and [DISCARD][discard-command] commands, as well as how Redis handles transactions atomically.
+
+      [redis-transactions]: https://redis.io/docs/latest/develop/interact/transactions/
+      [multi-command]: https://redis.io/commands/multi/
+      [exec-command]: https://redis.io/commands/exec/
+      [discard-command]: https://redis.io/commands/discard/
+
 stages:
   - slug: "jm1"
     concept_slugs:
@@ -1803,6 +1815,7 @@ stages:
       In this stage, you'll finish implementing the WAIT command on your master.
 
   # Streams
+
   - slug: "cc3"
     primary_extension_slug: "streams"
     name: "The TYPE command"
@@ -3142,3 +3155,313 @@ stages:
       - In the response, the items are separated onto new lines for readability. The tester expects all of these to be in one line.
     marketing_md: |
       In this stage, you'll add extend support to `XREAD` to allow for passing in `$` as the ID for a blocking command.
+
+  # Transactions
+
+  - slug: "si4"
+    primary_extension_slug: "transactions"
+    name: "INCR Command (1/3)"
+    difficulty: easy
+    description_md: |
+      **🚧 We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      ### Tests
+
+      The tester will execute your program as a master like this:
+
+      ```
+      ./spawn_redis_server.sh
+      ```
+
+      The tester will then connect to your master as a Redis client, and send multiple commands using the same connection:
+
+      ```bash
+      $ redis-cli SET foo 41
+      > INCR foo
+      ```
+
+    marketing_md: |
+      In this stage, you'll start implementing the INCR command.
+
+  - slug: "lz8"
+    primary_extension_slug: "transactions"
+    name: "INCR Command (2/3)"
+    difficulty: easy
+    description_md: |
+      **🚧 We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      ### Tests
+
+      The tester will execute your program as a master like this:
+
+      ```
+      ./spawn_redis_server.sh
+      ```
+
+      The tester will then connect to your master as a Redis client, and send multiple commands using the same connection:
+
+      ```bash
+      $ redis-cli INCR foo
+      > INCR bar
+      ```
+
+    marketing_md: |
+      In this stage, you'll continue implementing the INCR command.
+
+  - slug: "mk1"
+    primary_extension_slug: "transactions"
+    name: "INCR Command (3/3)"
+    difficulty: easy
+    description_md: |
+      **🚧 We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      ### Tests
+
+      The tester will execute your program as a master like this:
+
+      ```
+      ./spawn_redis_server.sh
+      ```
+
+      The tester will then connect to your master as a Redis client, and send multiple commands using the same connection:
+
+      ```bash
+      $ redis-cli SET foo xyz
+      > INCR foo
+      ```
+
+    marketing_md: |
+      In this stage, you'll finish implementing the INCR command.
+
+  - slug: "pn0"
+    primary_extension_slug: "transactions"
+    name: "MULTI Command"
+    difficulty: easy
+    description_md: |
+      **🚧 We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      ### Tests
+
+      The tester will execute your program as a master like this:
+
+      ```
+      ./spawn_redis_server.sh
+      ```
+
+      The tester will then connect to your master as a Redis client, and send multiple commands using the same connection:
+
+      ```bash
+      $ redis-cli MULTI
+      ```
+
+    marketing_md: |
+      In this stage, you'll implement the MULTI command.
+
+  - slug: "lo4"
+    primary_extension_slug: "transactions"
+    name: "EXEC Command"
+    difficulty: easy
+    description_md: |
+      **🚧 We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      ### Tests
+
+      The tester will execute your program as a master like this:
+
+      ```
+      ./spawn_redis_server.sh
+      ```
+
+      The tester will then connect to your master as a Redis client, and send multiple commands using the same connection:
+
+      ```bash
+      $ redis-cli EXEC
+      ```
+
+    marketing_md: |
+      In this stage, you'll start implementing the EXEC command.
+
+  - slug: "we1"
+    primary_extension_slug: "transactions"
+    name: "Empty transaction"
+    difficulty: hard
+    description_md: |
+      **🚧 We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      ### Tests
+
+      The tester will execute your program as a master like this:
+
+      ```
+      ./spawn_redis_server.sh
+      ```
+
+      The tester will then connect to your master as a Redis client, and send multiple commands using the same connection:
+
+      ```bash
+      $ redis-cli MULTI
+      > EXEC
+      > EXEC
+      ```
+
+    marketing_md: |
+      In this stage, you'll implement an empty transaction.
+
+  - slug: "rs9"
+    primary_extension_slug: "transactions"
+    name: "Queueing Commands"
+    difficulty: medium
+    description_md: |
+      **🚧 We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      ### Tests
+
+      The tester will execute your program as a master like this:
+
+      ```
+      ./spawn_redis_server.sh
+      ```
+
+      The tester will then connect to your master as a Redis client, and send multiple commands using the same connection:
+
+      ```bash
+      $ redis-cli MULTI
+      > SET foo 41
+      > INCR foo
+      ```
+
+      The tester will then create another connection to your master as a Redis client, and send a single command:
+
+      ```bash
+      $ redis-cli GET foo
+      ```
+
+    marketing_md: |
+      In this stage, you'll implement queueing commands to a transaction.
+
+  - slug: "fy6"
+    primary_extension_slug: "transactions"
+    name: "Executing a transaction"
+    difficulty: hard
+    description_md: |
+      **🚧 We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      ### Tests
+
+      The tester will execute your program as a master like this:
+
+      ```
+      ./spawn_redis_server.sh
+      ```
+
+      The tester will then connect to your master as a Redis client, and send multiple commands using the same connection:
+
+      ```bash
+      $ redis-cli MULTI
+      > SET foo 6
+      > INCR foo
+      > INCR bar
+      > GET bar
+      > EXEC
+      ```
+
+      The tester will then create another connection to your master as a Redis client, and send a single command:
+
+      ```bash
+      $ redis-cli GET foo
+      ```
+
+    marketing_md: |
+      In this stage, you'll implement executing a successful transaction.
+
+  - slug: "rl9"
+    primary_extension_slug: "transactions"
+    name: "DISCARD Command"
+    difficulty: easy
+    description_md: |
+      **🚧 We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      ### Tests
+
+      The tester will execute your program as a master like this:
+
+      ```
+      ./spawn_redis_server.sh
+      ```
+
+      The tester will then connect to your master as a Redis client, and send multiple commands using the same connection:
+
+      ```bash
+      $ redis-cli MULTI
+      > SET foo 41
+      > INCR foo
+      > DISCARD
+      > GET foo
+      > GET bar
+      > DISCARD
+      ```
+
+    marketing_md: |
+      In this stage, you'll implement the DISCARD command.
+
+  - slug: "sg9"
+    primary_extension_slug: "transactions"
+    name: "Failures within transactions"
+    difficulty: medium
+    description_md: |
+      **🚧 We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      ### Tests
+
+      The tester will execute your program as a master like this:
+
+      ```
+      ./spawn_redis_server.sh
+      ```
+
+      The tester will then connect to your master as a Redis client, and send multiple commands using the same connection:
+
+      ```bash
+      $ redis-cli SET foo abc
+      > SET bar 7 
+      > MULTI
+      > INCR foo
+      > INCR bar
+      > EXEC
+      ```
+
+      The tester will then create another connection to your master as a Redis client, and send a single command:
+
+      ```bash
+      $ redis-cli GET foo
+      > GET bar
+      ```
+
+    marketing_md: |
+      In this stage, you'll implement handling failures while executing a transaction.
+
+  - slug: "jf8"
+    primary_extension_slug: "transactions"
+    name: "Multiple transactions"
+    difficulty: medium
+    description_md: |
+      **🚧 We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      ### Tests
+
+      The tester will execute your program as a master like this:
+
+      ```
+      ./spawn_redis_server.sh
+      ```
+
+      The tester will then connect to your master as multiple Redis clients, and send multiple commands from each connection:
+
+      ```bash
+      $ redis-cli MULTI
+      > INCR foo
+      > EXEC
+      ```
+
+    marketing_md: |
+      In this stage, you'll implement multiple concurrent transactions.