### Description
This PR introduces three new features:
- Support for a new migrations folder structure.
- Add `squash` command in preview.
- ~List of migrations on the Console and ability to squash them from console.~
#### New migrations folder structure
Starting with this commit, Hasura CLI supports a new directory structure for migrations folder and defaults to that for all new migrations created.
Each migration will get a new directory with the name format `timestamp_name` and inside the directory, there will be four files:
```bash
└── migrations
├── 1572237730898_squashed
│ ├── up.sql
│ ├── up.yaml
│ ├── down.yaml
│ └── down.sql
```
Existing files old migration format `timestamp_name.up|down.yaml|sql` will continue to work alongside new migration files.
#### Squash command
Lots of users have expressed their interest in squashing migrations (see #2724 and #2254) and some even built [their own tools](https://github.com/domasx2/hasura-squasher) to do squash. In this PR, we take a systematic approach to squash migrations.
A new command called `migrate squash` is introduced. Note that this command is in **PREVIEW** and the correctness of squashed migration is not guaranteed (especially for down migrations). From our tests, **it works for most use cases**, but we have found some issues with squashing all the down migrations, partly because the console doesn't generate down migrations for all actions.
Hence, until we add an extensive test suite for squashing, we'll keep the command in preview. We recommend you to confirm the correctness yourself by diffing the SQL and Metadata before and after applying the squashed migrations (we're also thinking about embedding some checks into the command itself).
```bash
$ hasura migrate squash --help
(PREVIEW) Squash multiple migrations leading upto the latest one into a single migration file
Usage:
hasura migrate squash [flags]
Examples:
# NOTE: This command is in PREVIEW, correctness is not guaranteed and the usage may change.
# squash all migrations from version 1572238297262 to the latest one:
hasura migrate squash --from 1572238297262
Flags:
--from uint start squashing form this version
--name string name for the new squashed migration (default "squashed")
--delete-source delete the source files after squashing without any confirmation
```
### Affected components
<!-- Remove non-affected components from the list -->
- CLI
### Related Issues
<!-- Please make sure you have an issue associated with this Pull Request -->
<!-- And then add `(close #<issue-no>)` to the pull request title -->
<!-- Add the issue number below (e.g. #234) -->
Close#2724, Close#2254,
### Solution and Design
<!-- How is this issue solved/fixed? What is the design? -->
<!-- It's better if we elaborate -->
For the squash command, a state machine is implemented to track changes to Hasura metadata. After applying each action on the metadata state, a list of incremental changes is created.
### Steps to test and verify
1. Open console via cli and create some migrations.
2. Run `hasura migrate squash --from <version>`
### Limitations, known bugs & workarounds
<!-- Limitations of the PR, known bugs and suggested workarounds -->
<!-- Feel free to delete these comment lines -->
- The `squash` command is in preview
- Support for squashing from the console is WIP
- Support for squashing migrations that are not committed yet is planned.
- Un-tracking or dropping a table will cause inconsistent squashed down migration since console doesn't generate correct down migration.
- If cascade setting is set to `true` on any of the metadata action, generated migration may be wrong
### Description
Adds a `metadata diff` command to show comparisons between two different sets of Hasura metadata.
```
# Show changes between server metadata and the exported metadata file:
hasura metadata diff
# Show changes between server metadata and that in local_metadata.yaml:
hasura metadata diff local_metadata.yaml
# Show changes between metadata from metadata.yaml and metadata_old.yaml:
hasura metadata diff metadata.yaml metadata_old.yaml
```
Also adds a `--dry-run` flag to `metadata apply` command which will print the diff and exit rather than actually applying the metadata.
### Affected components
- CLI
- Docs
### Related Issues
Close#3126, Close#3127
### Solution and Design
- Added `metadata_diff.go` and `metadata_diff_test.go`
### Steps to test and verify
```
hasura metadata export
# Make changes to migrations/metadata.yaml
hasura metadata diff
```
### Limitations, known bugs & workarounds
This is just a general-purpose diff.
A more contextual diff with the understanding of metadata can be added once #3072 is merged.
* allow customizing GraphQL root field names, close#981
* document v2 track_table API in reference
* support customising column field names in GraphQL schema
* [docs] add custom column fields doc in API reference
* add tests
* rename 'ColField' to 'ColumnField'
* embed column's graphql field in 'PGColumnInfo'
-> Value constructor of 'PGCol' is not exposed
-> Using 'parseJSON' to construct 'PGCol' in 'FromJSON' instances
* avoid using 'Maybe TableConfig'
* refactors & 'custom_column_fields' -> 'custom_column_names'
* cli-test: add configuration field in metadata export test
* update expected keys in `FromJSON` instance of `TableMeta`
* use `buildSchemaCacheFor` to update configuration in v2 track_table
* remove 'GraphQLName' type and use 'isValidName' exposed from parser lib
* point graphql-parser-hs library git repo to hasura
* support 'set_table_custom_fields' query API & added docs and tests
These changes also add a new type, PGColumnType, between PGColInfo and
PGScalarType, and they process PGRawColumnType values into PGColumnType
values during schema cache generation.
query templates is a little known feature that lets you template rql
queries and serve them as rest apis. This is not relevant anymore
given the GraphQL interface and getting rid of it reduces the dev
time when adding features in few subsystems.
This feature has never been used outside hasura's internal projects or
documented or exposed through console and hence can safely be removed.
This PR builds console static assets into the server docker image at `/srv/console-assets`. When env var `HASURA_GRAPHQL_CONSOLE_ASSETS_DIR=/srv/console-assets` or flag `--console-assets-dir=/srv/console-assets` is set on the server, the files in this directory are served at `/console/assets/*`.
The console html template will have a variable called `cdnAssets: false` when this flag is set and it loads assets from server itself instead of CDN.
The assets are moved to a new bucket with a new naming scheme:
```
graphql-engine-cdn.hasura.io/console/assets/
/common/{}
/versioned/<version/{}
/channel/<channel>/<version>/{}
```
Console served by CLI will still load assets from CDN - will fix that in the next release.
The word "reset" is little ambiguous (reset to scratch or reset to last known consistent state). metadata reset clears the all the metadata to mimic a freshly installed hasura instance. This actually invokes the clear_metadata API in the backend and hence should also be called metadata clear for perfect clarity.
All references to metadata reset should be changed to metadata clear.
Rename the admin secret key header used to access GraphQL engine from X-Hasura-Access-Key to X-Hasura-Admin-Secret.
Server CLI and console all support the older flag but marks it as deprecated.
