# New Google Client Library Generation

The script allows you to create a new client library module in the
google-cloud-java monorepo.

**This tool is for repository maintainers only. Not for library users.**

## Prerequisites

This section is only needed for the first run of this script. If it's already
done, go to "Run client generation script" section.


### Environment

Use Linux environment.

Install Docker.

### Ensure no Release Please "snapshot" pull request open

Ensure google-cloud-java repository does not have [a pull request with "autorelease: snapshot" label](
https://github.com/googleapis/google-cloud-java/pulls?q=is%3Apr+is%3Aopen+label%3A%22autorelease%3A+snapshot%22).

If you find one, merge it after approving it.
This is a pull request to append "-SNAPSHOT" to versions in pom.xml files in the
repostiory. It's not for an actual release.

Background: This new client library generation process creates pom.xml files with
a "-SNAPSHOT" version. To have consistency with other modules, ensure the pom.xml files in
the repository has "-SNAPSHOT" versions too.


### Checkout google-cloud-java repository

```
$ git clone https://github.com/googleapis/google-cloud-java
$ git checkout main
$ git pull
```

### Install pyenv

Install pyenv

```
curl -L https://github.com/pyenv/pyenv-installer/raw/master/bin/pyenv-installer \
| bash
```

Append the following lines to `$HOME/.bashrc`.

```
export PYENV_ROOT="$HOME/.pyenv"
command -v pyenv >/dev/null || export PATH="$PYENV_ROOT/bin:$PATH"
eval "$(pyenv init -)"
eval "$(pyenv virtualenv-init -)"
```

Logout the shell and login again. You should be at the home directory.

Assuming you have the following folder structure:
```
~ (Home)
    -> IdeaProjects/
        -> google-cloud-java
    -> ...
```
You can run these next commands in the home directory (or IdeaProjects). Otherwise, run it at `google-cloud-java`'s parent directory.

Confirm pyenv installation succeeded:

```
~$ pyenv
pyenv 2.3.4
Usage: pyenv <command> [<args>]

Some useful pyenv commands are:
   activate    Activate virtual environment
   commands    List all available pyenv commands
   deactivate   Deactivate virtual environment
...
```

### Install Python 3.9 via pyenv

```
~$ pyenv install 3.9.13
Downloading Python-3.9.13.tar.xz...
-> https://www.python.org/ftp/python/3.9.13/Python-3.9.13.tar.xz
Installing Python-3.9.13...
WARNING: The Python sqlite3 extension was not compiled. Missing the SQLite3 lib?
Installed Python-3.9.13 to /usr/local/google/home/suztomo/.pyenv/versions/3.9.13
```

### Install Python v3.9.13 locally

Run this command

```
$ pyenv local 3.9.13
```

Confirm `python3.9` is installed:
```
$ which python3.9
/usr/local/google/home/suztomo/.pyenv/shims/python3.9
```

### Install Python packages

At the root of google-cloud-java repository clone, run:

```
$ python3.9 -m pip install -r generation/new_client/requirements.txt
```

### Install GitHub CLI (Optional)

Install the GitHub CLI and login, if needed (may help with `Common Errors` below):

```
$ sudo apt-get install gh
$ gh auth login
```

## Run client generation script

You will run new-client.py script with the following parameters.
Collect them from the ticket before running the command.

### API short name

For convenience of the subsequent commands, define a variable for API short name.
Get the value from the DevRel Services page (Example: `apikeys`):

### Proto path

The script takes "proto path" parameter. This is path from google3's root to the
directory that contains versions (e.g., "v1" or "v2"). For example, if we
have 

> Link to protos: http://google3/google/api/apikeys/v2/apikeys.proto

then the "proto path" value we supply to the command is "google/api/apikeys".

### Name pretty

Pick name from the display name in the DevRel Services site.
For example, "API Keys API" in
https://devrel.corp.google.com/admin/products/479.

### Product Docs

Find product document URL in the DevRel Services site.
For example, "https://cloud.google.com/api-keys/" in
https://devrel.corp.google.com/admin/products/479.
The value must starts with "https://".

### API description

Find the short description of the API. Usually the first sentence in the product
document above.

### Example arguments

Run `new-client.py` with the arguments above:

```
$ python3.9 generation/new_client/new-client.py generate \
  --api_shortname=apikeys \
  --proto-path=google/api/apikeys \
  --name-pretty="API Keys API" \
  --product-docs="https://cloud.google.com/api-keys/" \
  --api-description="API Keys lets you create and manage your API keys for your projects."
```

The command creates changes for
the new module in the monorepo. At the end (~ 10 minutes), it tells you to
create a pull request in the monorepo:

```
...
Please create a pull request:
  $ git checkout -b new_module_java-discoveryengine
  $ git add .
  $ git commit -m 'feat: [apikeys] new module for apikeys'
  $ gh pr create --title 'feat: [apikeys] new module for apikeys'
```

Create a pull request from the change.
In the description, record the `python3.9 generation/new_client/new-client.py generate ...`
command you ran above.

## Advanced Options

For the explanation of the available parameters, run:
`python3.9 generation/new_client/new-client.py generate  --help`.

```
~/google-cloud-java$ python3.9 generation/new_client/new-client.py generate  --help
/usr/local/google/home/suztomo/google-cloud-java/generation/new_client
Usage: new-client.py generate [OPTIONS]

Options:
  --api_shortname TEXT            Name for the new directory name and
                                  (default) artifact name  [required]
  --name-pretty TEXT              The human-friendly name that appears in
                                  README.md  [required]
  --product-docs TEXT             Documentation URL that appears in README.md
                                  [required]
  --api-description TEXT          Description that appears in README.md
                                  [required]
  --release-level [stable|preview]
                                  A label that appears in repo-metadata.json.
                                  The first library generation is always
                                  'preview'.  [default: preview]
  --transport [grpc|http|both]    A label that appears in repo-metadata.json
                                  [default: grpc]
  --language TEXT                 [default: java]
  --distribution-name TEXT        Maven coordinates of the generated library.
                                  By default it's com.google.cloud:google-
                                  cloud-<api_shortname>
  --api-id TEXT                   The value of the apiid parameter used in
                                  README.md It has link to https://console.clo
                                  ud.google.com/flows/enableapi?apiid=<api_id>
  --requires-billing BOOLEAN      Based on this value, README.md explains
                                  whether billing setup is needed or not.
                                  [default: True]
  --destination-name TEXT         The directory name of the new library. By
                                  default it's java-<api_shortname>
  --proto-path TEXT               Path to proto file from the root of the
                                  googleapis repository to thedirectory that
                                  contains the proto files (without the
                                  version).For example, to generate the
                                  library for 'google/maps/routing/v2', then
                                  you specify this value as
                                  'google/maps/routing'  [required]
  --cloud-api BOOLEAN             If true, the artifact ID of the library is
                                  'google-cloud-'; otherwise 'google-'
                                  [default: True]
  --group-id TEXT                 The group ID of the artifact when
                                  distribution name is not set  [default:
                                  com.google.cloud]
  --owlbot-image TEXT             The owlbot container image used in
                                  OwlBot.yaml  [default: gcr.io/cloud-devrel-
                                  public-resources/owlbot-java]
  --library-type TEXT             A label that appear in repo-metadata.json to
                                  tell how the library is maintained or
                                  generated  [default: GAPIC_AUTO]
  --googleapis-gen-url TEXT       The URL of the repository that has generated
                                  Java code from proto service definition
                                  [default:
                                  https://github.com/googleapis/googleapis-
                                  gen.git]
  --help                          Show this message and exit.
```

Sometimes, a library generation requires special handling for
Maven coordinates or API ID, especially when the library is not
specific to Google Cloud. Refer to the following command example when we
generated Google Maps Routes API Java client library.

```
~/google-cloud-java$ python3.9 generation/new_client/new-client.py generate \
  --api_shortname=maps-routing \
  --proto-path=google/maps/routing \
  --name-pretty="Routes API" \
  --product-docs="https://developers.google.com/maps/documentation/routes" \
  --api-description="Routes API is the next generation, performance optimized version of the existing Directions API and Distance Matrix API. It helps you find the ideal route from A to Z, calculates ETAs and distances for matrices of origin and destination locations, and also offers new features." \
  --api-id=routes.googleapis.com \
  --cloud-api=false \
  --requires-billing=true \
  --distribution-name="com.google.maps:google-maps-routing"
```

# Principles

The script should finish creating a pull request even when the newly created
module fails to compile. This gives the user flexibility to fix things in the
created pull request.

# Common Errors

## Unable to clone googleapis-gen
```
Creating a new module /usr/local/google/home/lawrenceqiu/IdeaProjects/google-cloud-java/java-vmwareengine
gcr.io/cloud-devrel-public-resources/owlbot-java:latest
Cloning googleapis-gen...
Username for 'https://github.com': xxxxxx
Password for 'https://xxxxxx@github.com': ******
remote: Support for password authentication was removed on August 13, 2021.
remote: Please see https://docs.github.com/en/get-started/getting-started-with-git/about-remote-repositories#cloning-with-https-urls for information on currently recommended modes of authentication.
fatal: Authentication failed for 'https://github.com/googleapis/googleapis-gen.git/'
Traceback (most recent call last):
  File "/usr/local/google/home/lawrenceqiu/IdeaProjects/google-cloud-java/generation/new_client/new-client.py", line 291, in <module>
    main()
  File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 1130, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 1055, in main
    rv = self.invoke(ctx)
  File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 1657, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 1404, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 760, in invoke
    return __callback(*args, **kwargs)
  File "/usr/local/google/home/lawrenceqiu/IdeaProjects/google-cloud-java/generation/new_client/new-client.py", line 180, in generate
    subprocess.check_call(["git", "clone", "-q", googleapis_gen_url, "./gen/googleapis-gen"], cwd=workdir)
  File "/usr/local/google/home/lawrenceqiu/.pyenv/versions/3.9.13/lib/python3.9/subprocess.py", line 373, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['git', 'clone', '-q', 'https://github.com/googleapis/googleapis-gen.git', './gen/googleapis-gen']' returned non-zero exit status 128.
```
### Solution
Run `gh auth login` and choose to authenticate with HTTPS. You may already be authenticated with SSH.
![img.png](img.png)

## Owl-bot Staging Directory Not Found
```
Removing googleapis-gen...
mv: cannot stat 'owl-bot-staging': No such file or directory
Traceback (most recent call last):
  File "/usr/local/google/home/lawrenceqiu/IdeaProjects/google-cloud-java/generation/new_client/new-client.py", line 291, in <module>
    main()
  File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 1130, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 1055, in main
    rv = self.invoke(ctx)
  File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 1657, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 1404, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 760, in invoke
    return __callback(*args, **kwargs)
  File "/usr/local/google/home/lawrenceqiu/IdeaProjects/google-cloud-java/generation/new_client/new-client.py", line 212, in generate
    subprocess.check_call(
  File "/usr/local/google/home/lawrenceqiu/.pyenv/versions/3.9.13/lib/python3.9/subprocess.py", line 373, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['mv', 'owl-bot-staging', '../']' returned non-zero exit status 1.
```

### Solution
The proto path is incorrect. See the `Proto Path` section to find the correct path.

## Python3.9 is not Installed
```
pyenv: version `3.9.13' is not installed (set by /workspace/.python-version)
Traceback (most recent call last):
File "/usr/local/google/home/lawrenceqiu/IdeaProjects/google-cloud-java/generation/new_client/new-client.py", line 291, in <module>
main()
File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 1130, in __call__
return self.main(*args, **kwargs)
File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 1055, in main
rv = self.invoke(ctx)
File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 1657, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 1404, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/usr/local/google/home/lawrenceqiu/.local/lib/python3.9/site-packages/click/core.py", line 760, in invoke
return __callback(*args, **kwargs)
File "/usr/local/google/home/lawrenceqiu/IdeaProjects/google-cloud-java/generation/new_client/new-client.py", line 223, in generate
subprocess.check_call(
File "/usr/local/google/home/lawrenceqiu/.pyenv/versions/3.9.13/lib/python3.9/subprocess.py", line 373, in check_call
raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['docker', 'run', '--rm', '-v', '/usr/local/google/home/lawrenceqiu/IdeaProjects/google-cloud-java:/workspace', '--user', '1023638:89939', 'gcr.io/cloud-devrel-public-resources/owlbot-java']' returned non-zero exit status 1.
```

### Solution
You have run the `pyenv local 3.9.13` in the `google-cloud-java` repo.
1. Remove the `.python-version` file in `google-cloud-java`.
2. `cd ..` out to the parent directory and run `pyenv local 3.9.13` there
3. `cd google-cloud-java` back into the repo and run the generation script again