Evaluate the env field

docs/references/deploy.yml.md

@@ -2,23 +2,44 @@
 
 ## Env
 
-Field                    |Type                    |Tag       |Description
----                      |----                    |---       |---
-`name`                   |*string*                |          |This parameter is the runtime environment such as `production`, `staging`, and `qa`. 
-`task`                   |*string*                |`github`  |This parameter is used by the deployment system to distinguish the kind of deployment. The default values is `deploy`, but for rollback, the value is always `rollback`.
-`description`            |*string*                |`github`  |This parameter is the short description of the deployment. The default value is `Gitploy starts to deploy.`
-`auto_merge`             |*boolean*               |`github`  |This parameter is used to ensure that the requested ref is not behind the repository's default branch. If you deploy with the commit or the tag you need to set `false`. The default values is `true`, but for rollback, the value is always `false`.
-`required_contexts`      |*[]string*              |`github`  |This parameter allows you to specify a subset of contexts that must be success. The default value is `nil`, it means every submitted context must be in a success state.
-`production_environment` |*boolean*               |`github`  |This parameter specifies whether this runtime environment is production or not.
-`approval`               |*[Approval](#approval)* |          |This parameter configures approval.
+
+Field                    |Type                     |Required  |Description
+---                      |----                     |---       |---
+`name`                   |*string*                 |`true`    |This field is the runtime environment such as `production`, `staging`, and `qa`. 
+`task`                   |*string*                 |`false`   |This field is used by the deployment system to distinguish the kind of deployment. 
+`description`            |*string*                 |`false`   |This field is the short description of the deployment. 
+`auto_merge`             |*boolean*                |`false`   |This field is used to ensure that the requested ref is not behind the repository's default branch. If you deploy with the commit or the tag you need to set `false`. For rollback, Gitploy set the field `false`.
+`required_contexts`      |*[]string*               |`false`   |This field allows you to specify a subset of contexts that must be success. 
+`production_environment` |*boolean*                |`false`   |This field specifies whether this runtime environment is production or not.
+`approval`               |*[Approval](#approval)*  |`false`   |This field configures approval.
 
 ## Approval
 
-Field            |Type      |Tag   |Description
----              |---       |---   |---
-`enabled`        |*boolean* |      |This parameter make to enable the approval feature. The default value is `false`.
-`required_count` |*integer* |      |This parameter determine how many the required approving approvals is needs to deploy. The default value is `0`.
+Field            |Type      |Tag     |Description
+---              |---       |---     |---
+`enabled`        |*boolean* |`true`  |This field make to enable the approval feature. The default value is `false`.
+`required_count` |*integer* |`false` |This field determine how many the required approving approvals is needs to deploy. The default value is `0`.
+
+## Variables
+
+The following variables are available in `${ }` syntax when evaluating `deploy.yml` before deploy or rollback:
+
+* `GITPLOY_DEPLOY_TASK`: Returns `deploy` for deploy, but rollback, it returns the empty string.
+* `GITPLOY_ROLLBACK_TASK`: Returns `rollback` for rollback, but deploy, it returns the empty string.
+* `GITPLOY_IS_ROLLBACK`: Returns `true` for rollback, but deploy, it returns `false`.
+
+An example usage of this:
+
+```yaml
+envs:
+  - name: prod
+    task: "${GITPLOY_DEPLOY_TASK}${GITPLOY_ROLLBACK_TASK}:kubernetes"  # It returns "deploy:kubernetes" or "rollback:kubernetes"
+```
 
-## Tags
+And Gitploy provides the string operation to facilitate customized values. You can check supported functions at [here](https://github.com/drone/envsubst).
 
-* `github`: Github specific field.
+```yaml
+envs:
+  - name: prod
+    task: "${GITPLOY_DEPLOY_TASK=rollback}:kubernetes" # It returns "deploy:kubernetes" or "rollback:kubernetes"
+```

go.mod

@@ -7,9 +7,9 @@ require (
 	entgo.io/ent v0.9.0
 	github.com/AlekSi/pointer v1.1.0
 	github.com/asaskevich/EventBus v0.0.0-20200907212545-49d423059eef
-	github.com/creasty/defaults v1.5.1
 	github.com/davecgh/go-spew v1.1.1
-	github.com/fvbock/endless v0.0.0-20170109170031-447134032cb6 // indirect
+	github.com/drone/envsubst v1.0.3
+	github.com/fvbock/endless v0.0.0-20170109170031-447134032cb6
 	github.com/gin-contrib/cors v1.3.1
 	github.com/gin-contrib/sse v0.1.0
 	github.com/gin-gonic/gin v1.7.2
@@ -33,6 +33,6 @@ require (
 	go.uber.org/zap v1.13.0
 	golang.org/x/net v0.0.0-20210525063256-abc453219eb5 // indirect
 	golang.org/x/oauth2 v0.0.0-20210514164344-f6687ab2804c
-	gopkg.in/h2non/gock.v1 v1.1.2 // indirect
+	gopkg.in/h2non/gock.v1 v1.1.2
 	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c
 )