4 files changed, 127 insertions, 0 deletions
diff --git a/u/process/env.ts b/u/process/env.ts
new file mode 100644
index 0000000..0e41b4f
--- /dev/null
+++ b/u/process/env.ts
@@ -0,0 +1,36 @@
+import { Either, type IEither } from "@emprespresso/pengueno";
+
+export const getRequiredEnv = <V extends string>(name: V): IEither<Error, V> =>
+  Either
+    .fromFailable<Error, V>(() => Deno.env.get(name) as V) // could throw when no permission.
+    .flatMap((v) =>
+      (v && Either.right(v)) ||
+      Either.left(
+        new Error(`environment variable "${name}" is required D:`),
+      )
+    );
+
+type ObjectFromList<T extends ReadonlyArray<string>, V = string> = {
+  [K in (T extends ReadonlyArray<infer U> ? U : never)]: V;
+};
+
+export const getRequiredEnvVars = <V extends string>(vars: ReadonlyArray<V>) =>
+  vars
+    .map((envVar) => [envVar, getRequiredEnv(envVar)] as [V, IEither<Error, V>])
+    .reduce(
+      (
+        acc: IEither<Error, ObjectFromList<typeof vars>>,
+        x: [V, IEither<Error, V>],
+      ) => {
+        const [envVar, eitherVal] = x;
+        return acc.flatMap((args) => {
+          return eitherVal.mapRight((envValue) =>
+            ({
+              ...args,
+              [envVar]: envValue,
+            }) as ObjectFromList<typeof vars>
+          );
+        });
+      },
+      Either.right({} as ObjectFromList<typeof vars>),
+    );
diff --git a/u/process/mod.ts b/u/process/mod.ts
new file mode 100644
index 0000000..3f02d46
--- /dev/null
+++ b/u/process/mod.ts
@@ -0,0 +1,3 @@
+export * from "./env.ts";
+export * from "./run.ts";
+export * from "./validate_identifier.ts";
diff --git a/u/process/run.ts b/u/process/run.ts
new file mode 100644
index 0000000..4954438
--- /dev/null
+++ b/u/process/run.ts
@@ -0,0 +1,64 @@
+import {
+  Either,
+  type IEither,
+  type ITraceable,
+  LogLevel,
+  TraceUtil,
+} from "@emprespresso/pengueno";
+
+export type Command = string[] | string;
+type CommandOutputDecoded = {
+  code: number;
+  stdoutText: string;
+  stderrText: string;
+};
+
+export const getStdout = <Trace>(
+  c: ITraceable<Command, Trace>,
+  options: Deno.CommandOptions = {},
+): Promise<IEither<Error, string>> =>
+  c.bimap(TraceUtil.withFunctionTrace(getStdout))
+    .map((tCmd) => {
+      const cmd = tCmd.get();
+      tCmd.trace.trace(`:> im gonna run this command! ${cmd}`);
+      const [exec, ...args] = (typeof cmd === "string") ? cmd.split(" ") : cmd;
+      return new Deno.Command(exec, {
+        args,
+        stdout: "piped",
+        stderr: "piped",
+        ...options,
+      }).output();
+    })
+    .map((tOut) =>
+      Either.fromFailableAsync<Error, Deno.CommandOutput>(tOut.get())
+    )
+    .map(
+      TraceUtil.promiseify((tEitherOut) =>
+        tEitherOut.get().flatMap(({ code, stderr, stdout }) =>
+          Either
+            .fromFailable<Error, CommandOutputDecoded>(() => {
+              const stdoutText = new TextDecoder().decode(stdout);
+              const stderrText = new TextDecoder().decode(stderr);
+              return { code, stdoutText, stderrText };
+            })
+            .mapLeft((e) => {
+              tEitherOut.trace.addTrace(LogLevel.ERROR).trace(`o.o wat ${e}`);
+              return new Error(`${e}`);
+            })
+            .flatMap((decodedOutput): Either<Error, string> => {
+              const { code, stdoutText, stderrText } = decodedOutput;
+              tEitherOut.trace.addTrace(LogLevel.DEBUG).trace(
+                `stderr hehehe ${stderrText}`,
+              );
+              if (code !== 0) {
+                const msg =
+                  `i weceived an exit code of ${code} i wanna zewoooo :<`;
+                tEitherOut.trace.addTrace(LogLevel.ERROR).trace(msg);
+                return Either.left(new Error(msg));
+              }
+              return Either.right(stdoutText);
+            })
+        )
+      ),
+    )
+    .get();
diff --git a/u/process/validate_identifier.ts b/u/process/validate_identifier.ts
new file mode 100644
index 0000000..32952a6
--- /dev/null
+++ b/u/process/validate_identifier.ts
@@ -0,0 +1,24 @@
+import { Either, type IEither } from "@emprespresso/pengueno";
+
+export const validateIdentifier = (token: string) => {
+  return (/^[a-zA-Z0-9_\-:. \/]+$/).test(token) && !token.includes("..");
+};
+
+// ensure {@param obj} is a Record<string, string> with stuff that won't
+// have the potential for shell injection, just to be super safe.
+type InvalidEntry<K, T> = [K, T];
+export const validateExecutionEntries = <
+  T,
+  K extends symbol | number | string = symbol | number | string,
+>(
+  obj: Record<K, T>,
+): IEither<
+  Array<InvalidEntry<K, T>>,
+  Record<string, string>
+> => {
+  const invalidEntries = <Array<InvalidEntry<K, T>>> Object.entries(obj).filter(
+    (e) => !e.every((x) => typeof x === "string" && validateIdentifier(x)),
+  );
+  if (invalidEntries.length > 0) return Either.left(invalidEntries);
+  return Either.right(<Record<string, string>> obj);
+};