From 32bfd936e744ea5881ecbaca1276c16f21a1c7d3 Mon Sep 17 00:00:00 2001
From: Moritz Poldrack <git@moritz.sh>
Date: Sun, 2 Jun 2024 12:12:12 +0200
Subject: [PATCH] add support for environment files

At times, it is necessary or at least easier to set environment
variables using a file.

Add a function that augments the environment of the spawned process with
the provided variables.

Signed-off-by: Moritz Poldrack <git@moritz.sh>
---
 runner/config.go       |  1 +
 runner/environment.go  | 30 ++++++++++++++++++++++++++++++
 runner/util_linux.go   |  4 ++++
 runner/util_unix.go    |  4 ++++
 runner/util_windows.go |  4 ++++
 5 files changed, 43 insertions(+)
 create mode 100644 runner/environment.go

diff --git a/runner/config.go b/runner/config.go
index 78a4eaa5..2d8bfeb4 100644
--- a/runner/config.go
+++ b/runner/config.go
@@ -58,6 +58,7 @@ type cfgBuild struct {
 	KillDelay        time.Duration `toml:"kill_delay"`
 	Rerun            bool          `toml:"rerun"`
 	RerunDelay       int           `toml:"rerun_delay"`
+	EnvironmentFile  string        `toml:"environment_file"`
 	regexCompiled    []*regexp.Regexp
 }
 
diff --git a/runner/environment.go b/runner/environment.go
new file mode 100644
index 00000000..55cb2438
--- /dev/null
+++ b/runner/environment.go
@@ -0,0 +1,30 @@
+package runner
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"os/exec"
+)
+
+func (e *Engine) modifyEnvironment(c *exec.Cmd) error {
+	if e.config.Build.EnvironmentFile == "" {
+		return nil
+	}
+
+	env := os.Environ()
+
+	envFile, err := os.Open(e.config.Build.EnvironmentFile)
+	if err != nil {
+		return fmt.Errorf("failed to open environment file: %w")
+	}
+	defer envFile.Close()
+
+	scan := bufio.NewScanner(envFile)
+	for scan.Scan() {
+		env = append(env, scan.Text())
+	}
+
+	c.Env = env
+	return nil
+}
diff --git a/runner/util_linux.go b/runner/util_linux.go
index 658671b3..d11ff93b 100644
--- a/runner/util_linux.go
+++ b/runner/util_linux.go
@@ -30,6 +30,10 @@ func (e *Engine) killCmd(cmd *exec.Cmd) (pid int, err error) {
 
 func (e *Engine) startCmd(cmd string) (*exec.Cmd, io.ReadCloser, io.ReadCloser, error) {
 	c := exec.Command("/bin/sh", "-c", cmd)
+	err := e.modifyEnvironment(c)
+	if err != nil {
+		return nil, nil, nil, err
+	}
 	f, err := pty.Start(c)
 	return c, f, f, err
 }
diff --git a/runner/util_unix.go b/runner/util_unix.go
index afd47c89..d9f2cb2a 100644
--- a/runner/util_unix.go
+++ b/runner/util_unix.go
@@ -33,6 +33,10 @@ func (e *Engine) startCmd(cmd string) (*exec.Cmd, io.ReadCloser, io.ReadCloser,
 	c.SysProcAttr = &syscall.SysProcAttr{
 		Setpgid: true,
 	}
+	err := e.modifyEnvironment(c)
+	if err != nil {
+		return nil, nil, nil, err
+	}
 
 	stderr, err := c.StderrPipe()
 	if err != nil {
diff --git a/runner/util_windows.go b/runner/util_windows.go
index eaa09e06..afe3fbf2 100644
--- a/runner/util_windows.go
+++ b/runner/util_windows.go
@@ -25,6 +25,10 @@ func (e *Engine) startCmd(cmd string) (*exec.Cmd, io.ReadCloser, io.ReadCloser,
 	if err != nil {
 		return nil, nil, nil, err
 	}
+	err = e.modifyEnvironment(c)
+	if err != nil {
+		return nil, nil, nil, err
+	}
 	stdout, err := c.StdoutPipe()
 	if err != nil {
 		return nil, nil, nil, err