Add README for pipedv1 (pipe-cd#5853)

Author: ffjlabo

cmd/pipedv1/README.md

@@ -0,0 +1,77 @@
+# Piped Agent for plugin architecture
+
+See [Overview of the Plan for Pluginnable PipeCD](https://pipecd.dev/blog/2024/11/28/overview-of-the-plan-for-pluginnable-pipecd/) to understand what's PipeCD plugin.
+
+
+## Prerequisites
+
+- [Go 1.24 or later](https://go.dev/)
+
+## Repositories
+- [pipecd](https://github.com/pipe-cd/pipecd): contains all source code and documentation of PipeCD project.
+
+## Commands
+
+- `make build/go`: builds all go modules including pipecd, piped, pipectl.
+- `make test/go`: runs all unit tests of go modules.
+- `make build/plugin`: builds built-in plugins located in `pkg/app/pipedv1/plugin`.
+- `make run/piped`: runs Piped locally (for more information, see [here](#how-to-run-piped-agent-locally)).
+- `make gen/code`: generate Go and Typescript code from protos and mock configs. You need to run it if you modified any proto or mock definition files.
+
+For the full list of available commands, please see the Makefile at the root of the repository.
+
+## Setup Control Plane
+
+1. Prepare Control Plane that piped connects. If you want to run a control plane locally, see [How to run Control Plane locally](https://github.com/pipe-cd/pipecd/tree/master/cmd/pipecd#how-to-run-control-plane-locally).
+
+2. Access to Control Plane console, go to Piped list page and add a new piped. Then, copy generated Piped ID and key for `piped-config.yaml`
+
+## How to run Piped agent locally
+
+1. Prepare plugin binaries.
+
+    ```sh
+    make build/plugin
+    ```
+
+2. Prepare the piped configuration file `piped-config.yaml`. This is an example configuration;
+    ```yaml
+    apiVersion: pipecd.dev/v1beta1
+    kind: Piped
+    spec:
+      projectID: quickstart
+      # FIXME: Replace here with your piped ID.
+      pipedID: 7accd470-1786-49ee-ac09-3c4d4e31dc12
+      # Base64 encoded string of the piped private key. You can generate it by the following command.
+      # echo -n "your-piped-key" | base64
+      # FIXME: Replace here with your piped key file path.
+      pipedKeyData: OTl4c2RqdjUxNTF2OW1sOGw5ampndXUyZjB2aGJ4dGw0bHVkamF4Mmc3a3l1enFqY20K
+      # Write in a format like "host:443" because the communication is done via gRPC.
+      # FIXME: Replace here with your piped address if you connect Piped to a control plane that does not run locally.
+      apiAddress: localhost:8080
+      repositories:
+      - repoId: example
+        remote: [email protected]:pipe-cd/examples.git # FIXME: prepare your manifest repo
+        branch: main
+      syncInterval: 1m
+      plugins:
+      - name: kubernetes
+        port: 7003 # FIXME: any unused port
+        url: file:///path/to/.piped/plugins/kubernetes # It's OK using any value for now because it's a dummy. We will implement it later.
+        deployTargets: # This field is alternative for platform providers
+        - name: kubernetes-dev
+          config:
+            masterURL: https://127.0.0.1:61337 # FIXME: shown by kubectl cluster-info
+            # FIXME: Replace here with your kubeconfig absolute file path.
+            kubeConfigPath: /path/to/.kube/config
+    ```
+
+3. Ensure that your `kube-context` is connecting to the right kubernetes cluster
+
+4. Run the following command to start running `piped` (if you want to connect Piped to a locally running Control Plane, add `INSECURE=true` option)
+
+    ``` console
+    make run/piped CONFIG_FILE=piped-config.yaml EXPERIMENTAL=true
+    ```
+
+Note: If you have a problem with accessing the example repository, please follow [this guide](https://docs.github.com/en/authentication/connecting-to-github-with-ssh/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent) to register the SSH key or try specifying `remote: https://github.com/pipe-cd/examples.git` instead in the above `piped-config.yaml`.