add dependency upgrade task (DataDog#1270)

* start

* finish

* remove script

* remove unused imports

* use invoke ctx cd

* fix typo

* address comments

* let git decide

* update docstring

tasks.py

@@ -1,5 +1,12 @@
 from __future__ import print_function, unicode_literals
+
+import os
+from io import open
+
 from invoke import task
+from invoke.exceptions import Exit
+
+HERE = os.path.dirname(os.path.abspath(__file__))
 
 # Note: these are the names of the folder containing the check
 AGENT_BASED_INTEGRATIONS = [
@@ -14,6 +21,23 @@
     'vsphere',
 ]
 
+
+def ensure_deps_declared(reqs_txt, reqs_in):
+    if os.path.isfile(reqs_txt) and not os.path.isfile(reqs_in):
+        declacred_lines = []
+
+        with open(reqs_txt, 'r', encoding='utf-8') as f:
+            lines = f.readlines()
+
+        for line in lines:
+            line = line.split('--hash')[0].strip('\r\n \\')
+            if line and not line.startswith('#'):
+                declacred_lines.append(line + '\n')
+
+        with open(reqs_in, 'w', encoding='utf-8') as f:
+            f.writelines(declacred_lines)
+
+
 @task(help={
     'targets': "Comma separated names of the checks that will be tested",
     'changed-only': "Whether to only test checks that were changed in a PR",
@@ -23,7 +47,7 @@ def test(ctx, targets=None, changed_only=False, dry_run=False):
     """
     Run the tests for Agent-based checks
 
-    Example invokation:
+    Example invocation:
         inv test --targets=disk,redisdb
     """
     if targets is None:
@@ -43,6 +67,7 @@ def test(ctx, targets=None, changed_only=False, dry_run=False):
             print("\nRunning tox in '{}'\n".format(check))
             ctx.run('tox')
 
+
 def integrations_changed(ctx):
     """
     Find out which checks were changed in the current branch
@@ -53,3 +78,63 @@ def integrations_changed(ctx):
         if line:
             checks.add(line.split('/')[0])
     return checks
+
+
+@task(help={
+    'package': 'The package to upgrade throughout the integrations',
+    'version': 'The version of the package to pin',
+    'verbose': 'Whether or not to produce output',
+})
+def upgrade(ctx, package=None, version=None, verbose=False):
+    """Upgrade a dependency for all integrations that require it.
+    ``pip-compile`` must be in PATH.
+
+    Example invocation:
+        inv upgrade --verbose -p=requests -v=2.18.4
+    """
+    if not (package and version):
+        raise Exit('`package` and `version` are required arguments.')
+
+    for check_name in sorted(os.listdir(HERE)):
+        check_dir = os.path.join(HERE, check_name)
+        reqs_in = os.path.join(check_dir, 'requirements.in')
+        reqs_txt = os.path.join(check_dir, 'requirements.txt')
+
+        ensure_deps_declared(reqs_txt, reqs_in)
+
+        if os.path.isfile(reqs_in):
+            with open(reqs_in, 'r', encoding='utf-8') as f:
+                lines = f.readlines()
+
+            for i, line in enumerate(lines):
+                try:
+                    pkg = line.split('=')[0].strip()
+                    if pkg == package:
+                        break
+                except IndexError:
+                    continue
+            # Skip integrations that don't require the package.
+            else:
+                continue
+
+            if verbose:
+                print('Check `{}`:'.format(check_name))
+                print('    Old: `{}`'.format(lines[i].strip()))
+
+            lines[i] = '{}=={}\n'.format(package, version)
+
+            with open(reqs_in, 'w', encoding='utf-8') as f:
+                f.writelines(lines)
+
+            if verbose:
+                print('    New: `{}`'.format(lines[i].strip()))
+                print('    Locking dependencies...')
+
+            with ctx.cd(check_dir):
+                ctx.run(
+                    'pip-compile '
+                    '--generate-hashes '
+                    '--output-file requirements.txt '
+                    'requirements.in',
+                    hide='both'
+                )