Implement env_file directive support

.gitignore

@@ -34,3 +34,4 @@ TODO.md
 __debug_bin*
 # Added by goreleaser init:
 dist/
+.env

cmd/lets/main.go

@@ -124,7 +124,7 @@ func main() {
 		if errors.As(err, &depErr) {
 			executor.PrintDependencyTree(depErr, os.Stderr)
 		}
-		log.Error(err.Error())
+		log.Errorf("lets: %s", err.Error())
 		os.Exit(getExitCode(err, 1))
 	}
 }

docs/docs/changelog.md

@@ -10,6 +10,7 @@ title: Changelog
 * `[Added]` Expose `LETS_OS` and `LETS_ARCH` environment variables at command runtime.
 * `[Removed]` Drop deprecated `eval_env` directive. Use `env` with `sh` execution mode instead.
 * `[Added]` When a command or its `depends` chain fails, print an indented tree to stderr showing the full chain with the failing command highlighted
+* `[Added]` Support `env_file` in global config and commands. File names are expanded after `env` is resolved, and values loaded from env files override values from `env`.
 
 ## [0.0.59](https://github.com/lets-cli/lets/releases/tag/v0.0.59)
 

docs/docs/config.md

@@ -101,6 +101,58 @@ env:
     sh: echo "${ENGINE}-compose"
 ```
 
+### Global env_file
+
+`key: env_file`
+
+`type: string | map | list`
+
+Load one or more dotenv-style files and expose their values to all commands.
+
+Supported forms:
+
+```yaml
+env_file: .env
+env_file: -.env.local
+env_file:
+  name: .env.${TARGET}
+  required: false
+env_file:
+  - .env
+  - -.env.local
+  - name: .env.${LETS_OS}
+    required: true
+```
+
+Rules:
+
+- `-filename` is a short form of `required: false`
+- files are resolved relative to the config directory
+- file names are expanded after global `env` is resolved, so `env_file` can depend on global `env`
+- values loaded from `env_file` have higher precedence than values from `env`
+- missing files fail by default
+- invalid env file syntax reports an error with the file name
+
+Example:
+
+```yaml
+shell: bash
+
+env:
+  TARGET: dev
+  ENGINE: docker
+
+env_file:
+  - .env.${TARGET}
+  - -.env.local
+
+commands:
+  echo-env:
+    cmd: |
+      echo ENGINE=${ENGINE}
+      echo API_URL=${API_URL}
+```
+
 ### Global before
 
 `key: before`
@@ -696,6 +748,43 @@ commands:
 ```
 
 
+### `env_file`
+
+`key: env_file`
+
+`type: string | map | list`
+
+Load dotenv-style env files for a single command.
+
+Rules:
+
+- command `env` is resolved first
+- command `env_file` file names are expanded using builtin lets vars, merged global env, and resolved command `env`
+- values loaded from command `env_file` override values from command `env`
+- paths are resolved relative to the config directory, not `work_dir`
+
+Example:
+
+```yaml
+shell: bash
+
+env:
+  TARGET: dev
+
+commands:
+  up:
+    env:
+      SUFFIX: local
+      ENGINE: docker
+    env_file:
+      - .env.${TARGET}.${SUFFIX}
+      - -.env.override
+    cmd: |
+      echo ENGINE=${ENGINE}
+      echo API_URL=${API_URL}
+```
+
+
 ### `checksum`
 
 `key: checksum`

docs/docs/env.md

@@ -27,6 +27,28 @@ title: Environment
 
 ### Override command env with -E flag
 
+### `env_file` precedence
+
+`env_file` loads dotenv-style files from config and command definitions.
+
+Precedence order is:
+
+* process env
+* builtin lets vars
+* global `env`
+* global `env_file`
+* command `env`
+* command `env_file`
+* command options, `-E` / `--env`, checksum vars
+
+When the same key is present in both directives, `env_file` wins over `env` at the same scope.
+
+`env_file` file names are expanded after `env` is resolved. This means:
+
+* global `env_file` can depend on global `env`
+* command `env_file` can depend on merged global env and command `env`
+* `env.sh` still does not read values from `env_file`
+
 You can override environment for command with `-E` flag:
 
 ```yaml

docs/static/schema.json

@@ -42,6 +42,9 @@
     "env": {
       "$ref": "#/definitions/env"
     },
+    "env_file": {
+      "$ref": "#/definitions/env_file"
+    },
     "before": {
       "type": "string",
       "description": "Commands to run before the main script."
@@ -137,6 +140,9 @@
         "env": {
           "$ref": "#/definitions/env"
         },
+        "env_file": {
+          "$ref": "#/definitions/env_file"
+        },
         "after": {
           "type": "string",
           "description": "A shell sctipt to run after the command."
@@ -192,6 +198,45 @@
         }
       },
       "additionalProperties": false
+    },
+    "env_file_entry": {
+      "oneOf": [
+        {
+          "type": "string",
+          "description": "Path to an env file. Prefix with '-' to make it optional."
+        },
+        {
+          "type": "object",
+          "properties": {
+            "name": {
+              "type": "string",
+              "description": "Path to an env file."
+            },
+            "required": {
+              "type": "boolean",
+              "description": "Whether the env file must exist. Defaults to true."
+            }
+          },
+          "required": [
+            "name"
+          ],
+          "additionalProperties": false
+        }
+      ]
+    },
+    "env_file": {
+      "description": "Env file or list of env files to load.",
+      "oneOf": [
+        {
+          "$ref": "#/definitions/env_file_entry"
+        },
+        {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/env_file_entry"
+          }
+        }
+      ]
     }
   },
   "additionalProperties": false

go.mod

@@ -40,6 +40,7 @@ require (
 require (
 	github.com/h2non/filetype v1.1.1 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/joho/godotenv v1.5.1
 	github.com/juju/errors v0.0.0-20200330140219-3fe23663418f // indirect
 	github.com/juju/testing v0.0.0-20201216035041-2be42bba85f3 // indirect
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51

go.sum

@@ -20,6 +20,8 @@ github.com/iancoleman/strcase v0.3.0 h1:nTXanmYxhfFAMjZL34Ov6gkzEsSJZ5DbhxWjvSAS
 github.com/iancoleman/strcase v0.3.0/go.mod h1:iwCmte+B7n89clKwxIoIXy/HfoL7AsD47ZCWhYzw7ho=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
+github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
+github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
 github.com/juju/ansiterm v0.0.0-20160907234532-b99631de12cf/go.mod h1:UJSiEoRfvx3hP73CvoARgeLjaIOjybY9vj8PUPPFGeU=
 github.com/juju/clock v0.0.0-20190205081909-9c5c9712527c/go.mod h1:nD0vlnrUjcjJhqN5WuCWZyzfd5AHZAC9/ajvbSx69xA=
 github.com/juju/cmd v0.0.0-20171107070456-e74f39857ca0/go.mod h1:yWJQHl73rdSX4DHVKGqkAip+huBslxRwS8m9CrOLq18=

internal/config/config/command.go

@@ -25,6 +25,8 @@ type Command struct {
 	Description string
 	// env from command
 	Env *Envs
+	// env files from command
+	EnvFiles *EnvFiles
 	// store docopts from options directive
 	Docopts         string
 	SkipDocopts     bool // default false
@@ -62,6 +64,7 @@ func (c *Command) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		Description     string
 		Shell           string
 		Env             *Envs
+		EnvFiles        *EnvFiles `yaml:"env_file"`
 		Options         string
 		Depends         *Deps
 		WorkDir         string `yaml:"work_dir"`
@@ -87,6 +90,10 @@ func (c *Command) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	if c.Env == nil {
 		c.Env = &Envs{}
 	}
+	c.EnvFiles = cmd.EnvFiles
+	if c.EnvFiles == nil {
+		c.EnvFiles = &EnvFiles{}
+	}
 
 	c.Shell = cmd.Shell
 	c.Docopts = cmd.Options
@@ -126,12 +133,37 @@ func (c *Command) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	return nil
 }
 
-func (c *Command) GetEnv(cfg Config) (map[string]string, error) {
-	if err := c.Env.Execute(cfg, cfg.GetEnv()); err != nil {
+func (c *Command) GetEnv(cfg Config, builtinEnv map[string]string) (map[string]string, error) {
+	baseEnv := cloneMap(builtinEnv)
+	if baseEnv == nil {
+		baseEnv = make(map[string]string)
+	}
+	for key, value := range cfg.GetEnv() {
+		baseEnv[key] = value
+	}
+
+	envs := c.Env.Clone()
+	if err := envs.Execute(cfg, baseEnv); err != nil {
 		return nil, err
 	}
 
-	return c.Env.Dump(), nil
+	filenameEnv := cloneMap(baseEnv)
+	for key, value := range envs.Dump() {
+		filenameEnv[key] = value
+	}
+
+	envFiles := c.EnvFiles.Clone()
+	envFileEnv, err := envFiles.Load(cfg, filenameEnv)
+	if err != nil {
+		return nil, fmt.Errorf("lets: failed to resolve env_file for command '%s': %w", c.Name, err)
+	}
+
+	resolvedEnv := envs.Dump()
+	for key, value := range envFileEnv {
+		resolvedEnv[key] = value
+	}
+
+	return resolvedEnv, nil
 }
 
 func (c *Command) Clone() *Command {
@@ -144,6 +176,7 @@ func (c *Command) Clone() *Command {
 		WorkDir:            c.WorkDir,
 		Description:        c.Description,
 		Env:                c.Env.Clone(),
+		EnvFiles:           c.EnvFiles.Clone(),
 		Docopts:            c.Docopts,
 		SkipDocopts:        c.SkipDocopts,
 		Options:            cloneMap(c.Options),