infra: accelerate builds (open-telemetry#693)

Some build time improvements:

- split lint/docker-tests/docs into their own steps. Since lint is usually the thing that fails anyways, it's good to have it run first. We could make the build depend on this step to prevent slowing other builds waiting in the pipeline (since we only have 5 workers)
- move all pip install commands into a single line per test environment. this reduces the overhead of calling the pip command separately multiple times per environment.
- removed pip upgrade command for pypy3 and py38

.travis.yml

@@ -4,13 +4,20 @@ language: python
 
 cache: pip
 
-python:
-  - 'pypy3'
-  - '3.8'
-  - '3.4'
-  - '3.5'
-  - '3.6'
-  - '3.7'
+matrix:
+  include:
+    - python: 3.8
+      env: TOXENV=lint
+    - python: pypy3
+    - python: 3.8
+    - python: 3.4
+    - python: 3.5
+    - python: 3.6
+    - python: 3.7
+    - python: 3.8
+      env: TOXENV=docker-tests
+    - python: 3.8
+      env: TOXENV=docs
 
 #matrix:
 #  allow_failures:

tox.ini

@@ -115,10 +115,6 @@ envlist =
     docs
     docker-tests
 
-[travis]
-python =
-  3.8: py38, lint, docs, docker-tests
-
 [testenv]
 deps =
   -c dev-requirements.txt
@@ -159,26 +155,16 @@ changedir =
 
 commands_pre =
 ; Install without -e to test the actual installation
-  python -m pip install -U pip setuptools wheel
-
+  py3{4,5,6,7}: python -m pip install -U pip setuptools wheel
 ; Install common packages for all the tests. These are not needed in all the
 ; cases but it saves a lot of boilerplate in this file.
-  test: pip install {toxinidir}/opentelemetry-api
-  test: pip install {toxinidir}/opentelemetry-sdk
-  test: pip install {toxinidir}/tests/util
+  test: pip install {toxinidir}/opentelemetry-api {toxinidir}/opentelemetry-sdk {toxinidir}/tests/util
 
   test-auto-instrumentation: pip install {toxinidir}/opentelemetry-auto-instrumentation
 
-  example-app: pip install {toxinidir}/opentelemetry-auto-instrumentation
-  example-app: pip install {toxinidir}/ext/opentelemetry-ext-requests
-  example-app: pip install {toxinidir}/ext/opentelemetry-ext-wsgi
-  example-app: pip install {toxinidir}/ext/opentelemetry-ext-flask
-  example-app: pip install {toxinidir}/docs/examples/opentelemetry-example-app
+  example-app: pip install {toxinidir}/opentelemetry-auto-instrumentation {toxinidir}/ext/opentelemetry-ext-requests {toxinidir}/ext/opentelemetry-ext-wsgi {toxinidir}/ext/opentelemetry-ext-flask {toxinidir}/docs/examples/opentelemetry-example-app
 
-  getting-started: pip install -e {toxinidir}/opentelemetry-auto-instrumentation
-  getting-started: pip install -e {toxinidir}/ext/opentelemetry-ext-requests
-  getting-started: pip install -e {toxinidir}/ext/opentelemetry-ext-wsgi
-  getting-started: pip install -e {toxinidir}/ext/opentelemetry-ext-flask
+  getting-started: pip install -e {toxinidir}/opentelemetry-auto-instrumentation -e {toxinidir}/ext/opentelemetry-ext-requests -e {toxinidir}/ext/opentelemetry-ext-wsgi -e {toxinidir}/ext/opentelemetry-ext-flask
 
   grpc: pip install {toxinidir}/ext/opentelemetry-ext-grpc[test]
 
@@ -191,48 +177,35 @@ commands_pre =
 
   django: pip install {toxinidir}/ext/opentelemetry-ext-django[test]
 
-  mysql: pip install {toxinidir}/opentelemetry-auto-instrumentation
-  mysql: pip install {toxinidir}/ext/opentelemetry-ext-dbapi
-  mysql: pip install {toxinidir}/ext/opentelemetry-ext-mysql[test]
+  mysql: pip install {toxinidir}/opentelemetry-auto-instrumentation {toxinidir}/ext/opentelemetry-ext-dbapi {toxinidir}/ext/opentelemetry-ext-mysql[test]
 
   otcollector: pip install {toxinidir}/ext/opentelemetry-ext-otcollector
 
   prometheus: pip install {toxinidir}/ext/opentelemetry-ext-prometheus
 
-  pymongo: pip install {toxinidir}/opentelemetry-auto-instrumentation
-  pymongo: pip install {toxinidir}/ext/opentelemetry-ext-pymongo[test]
+  pymongo: pip install {toxinidir}/opentelemetry-auto-instrumentation {toxinidir}/ext/opentelemetry-ext-pymongo[test]
 
-  psycopg2: pip install {toxinidir}/opentelemetry-auto-instrumentation
-  psycopg2: pip install {toxinidir}/ext/opentelemetry-ext-dbapi
-  psycopg2: pip install {toxinidir}/ext/opentelemetry-ext-psycopg2[test]
+  psycopg2: pip install {toxinidir}/opentelemetry-auto-instrumentation {toxinidir}/ext/opentelemetry-ext-dbapi {toxinidir}/ext/opentelemetry-ext-psycopg2 {toxinidir}/ext/opentelemetry-ext-psycopg2[test]
 
-  pymysql: pip install {toxinidir}/opentelemetry-auto-instrumentation
-  pymysql: pip install {toxinidir}/ext/opentelemetry-ext-dbapi
-  pymysql: pip install {toxinidir}/ext/opentelemetry-ext-pymysql[test]
+  pymysql: pip install {toxinidir}/opentelemetry-auto-instrumentation {toxinidir}/ext/opentelemetry-ext-dbapi {toxinidir}/ext/opentelemetry-ext-pymysql[test]
 
-  redis: pip install {toxinidir}/opentelemetry-auto-instrumentation
-  redis: pip install {toxinidir}/ext/opentelemetry-ext-redis[test]
+  redis: pip install {toxinidir}/opentelemetry-auto-instrumentation {toxinidir}/ext/opentelemetry-ext-redis[test]
 
-  requests: pip install {toxinidir}/opentelemetry-auto-instrumentation
-  requests: pip install {toxinidir}/ext/opentelemetry-ext-requests[test]
+  requests: pip install {toxinidir}/opentelemetry-auto-instrumentation {toxinidir}/ext/opentelemetry-ext-requests[test]
 
-  jinja2: pip install {toxinidir}/opentelemetry-auto-instrumentation
-  jinja2: pip install {toxinidir}/ext/opentelemetry-ext-jinja2[test]
+  jinja2: pip install {toxinidir}/opentelemetry-auto-instrumentation {toxinidir}/ext/opentelemetry-ext-jinja2[test]
 
-  aiohttp-client: pip install {toxinidir}/opentelemetry-sdk
-  aiohttp-client: pip install {toxinidir}/ext/opentelemetry-ext-aiohttp-client
+  aiohttp-client: pip install {toxinidir}/opentelemetry-sdk {toxinidir}/ext/opentelemetry-ext-aiohttp-client
 
   jaeger: pip install {toxinidir}/ext/opentelemetry-ext-jaeger
 
-  datadog: pip install {toxinidir}/opentelemetry-sdk
-  datadog: pip install {toxinidir}/ext/opentelemetry-ext-datadog
+  datadog: pip install {toxinidir}/opentelemetry-sdk {toxinidir}/ext/opentelemetry-ext-datadog
 
   opentracing-shim: pip install {toxinidir}/ext/opentelemetry-ext-opentracing-shim
 
   zipkin: pip install {toxinidir}/ext/opentelemetry-ext-zipkin
 
-  sqlalchemy: pip install {toxinidir}/opentelemetry-auto-instrumentation
-  sqlalchemy: pip install {toxinidir}/ext/opentelemetry-ext-sqlalchemy
+  sqlalchemy: pip install {toxinidir}/opentelemetry-auto-instrumentation {toxinidir}/ext/opentelemetry-ext-sqlalchemy
 
 ; In order to get a healthy coverage report,
 ; we have to install packages in editable mode.